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Posts Tagged ‘exercise

HIT, mitochondria and health

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comparing-hit-with-other-exercise

 

and for a gentler form of exercise...

and for a gentler form of exercise…

Jacinta: Well now, I know you’re dying to explore the recently touted benefits of your favourite exercise, so let’s have it.

Canto: Yes, I’m very much a HIT man, that’s high intensity interval training, highly recommendable because it takes so little time and only requires an exercise bike. I was put onto it by one of Michael Mosley’s documentaries, though I’ve been a rather theoretical enthusiast in recent times, having trouble overcoming my laziness and my pain-avoidance tendencies, because though it’s short exercise it is a little painful.

Jacinta: So the recent Catalyst episode has brought your enthusiasm surging back?

Canto: Naturellement, especially as it brings with it some new research to focus on. Mitochondria – what do you know about them?

Jacinta: That they are organelles in our cells, believed to have originated as bacteria but to have united with our eukaryotic cells way back in time in a process known as endosymbiosis. They’re also responsible for producing ATP, the energy molecules… though I’ve no idea how, or what an energy molecule actually is.

Canto: That’s music to my ears.

Jacinta: The dulcet tones of ignorance?

Canto: In the country of the blind the one-eyed science pundit is king, and I’d rather be a king than a commoner, so hear ye, my subject.

Jacinta: I may be blind but I’m all ears, Your Majesty.

Canto: Well, as the Catalyst program tells us, mitochondria are about a billion times smaller than a grain of sand, but the world at nanoscales has really opened up to us in recent decades. Mitochondria are good for us, and the more the merrier. And the evidence is that HIT exercise can not only increase the production of mitochondria but increase their function.

Jacinta: So how do we produce mitochondria?

Canto: Are you going to keep interrupting me with questions? Okay, the production of mitochondria relies on our oxygen intake. The story goes that we fill our lungs with oxygen and it enters the bloodstream for a specific purpose…

Jacinta: Hang on, we fill our lungs with air, not just oxygen, so how does the oxygen get separated, and how does the blood take up the oxygen? Aren’t you skipping a few steps here?

Canto: Yes, go and research it yourself and you can report on it next time. The destination of this inhaled oxygen is the mitochondria. There are billions of these mitochondria in our musculature, though the more fit and trained up you are, the more you’re likely to have. Mitochondria apparently comprise some 10% of our body mass, which I’m sure will come as a surprise. Now oxygen, as you know, acts as a corrosive through the process known as oxidation, which involves the loss of electrons…

Jacinta: Hang on…

Canto: Please shut up. So oxygen can have a negative effect on proteins, enzymes and even our DNA, but mitochondria uses this corrosive electron-stripping power to break down nutrients and to create energy in the form of adenosine triphosphate (ATP). Don’t ask! Of course this doesn’t just happen in humans but in all other mammals and complex creatures, and in plants. And that brings us to physical fitness, and the VO2 Max, which is, essentially, the measure of the fitness of our mitochondria. The term stands for volume (V), oxygen (O2), and of course maximum, though generally those concerned with aerobic fitness don’t make the association with mitochondria, they’re just looking at increasing their maximum oxygen consumption levels. Now it’s not an easy thing for impoverished nonentities like us to find out what our VO2 Max is, but it’s probably pretty pathetic. It’s something that endurance athletes tend to obsess about as they try to improve their performance – I believe rowers in particular have some of the highest levels. I notice there’s at least one VO2 Max app on the market – going very cheap too – but I’d be very sceptical about its reliability. In the testing facility shown on Catalyst they measure it via a version of HIT. They get the subject to ride an exercise bike, building up speed till she’s going as fast as she can, and she can go no faster and starts slowing down. That peak represents her VO2 Max. She will be tested 16 weeks later, after a mere 6 minutes of HIT a week, and you can bet your rented house that her VO2 Max will have substantially improved.

Jacinta: So for us low-lifes – excuse my interruption – who can’t easily or cheaply measure improvements in our VO2 Max or, say, our fat to muscle ratio, we just have to feel the difference in aerobic fitness, mitochondrial health and the like…

Canto: Yeah, and your weight will go down too, if you’re carrying a bit extra, as we both are. And the exertion will make you feel better and healthier, I guarantee it. We all know that the placebo effect is real after all. But seriously, I’m sure if we keep to a regime of HIT – say 3 bursts of 20-second full-pelt pedalling interspersed with a minute or so of more relaxed pedalling, or even if we start with 10-second bursts and then 15-second bursts, maybe eventually getting up to 30-second bursts, we’ll feel it getting easier, and it won’t be purely subjective even if we have no way of objectively measuring it.

Jacinta: But shouldn’t we consult a doctor beforehand? I already feel a heart-attack coming on.

Canto: I know you’re joking, but certainly anyone who has any kind of heart condition, or are diabetic or pre-diabetic or have any other serious chronic condition should discuss it with their GP, but really, apart from your couch potato tendencies, there’s nothing wrong with you.

Jacinta: You’re right, and I’m looking forward to the challenge, even though I’m already a to-die-for, effortlessly slim, perpetually twenty-two year old intellectual beauty..

Canto: And I’m the ultimate metrosexual hipster of indeterminate age and shoe size, discreetly tattooed and tucked…

Jacinta: Ah, yuck, you stupid twat, tattoos are the most repugnant fashion development of all time. At least you’re not a spornosexual, yuk, stay away from the gym or I’ll never speak to you again .

Canto: Promise? Anyway, around 35 is the average VO2 Max, but that’s a bit meaningless for us low-lifes as you say. Top athletes have levels in the 60s and 70s, with the highest ever recorded being around 96 or 97 for humans, but some mammals – like racehorses and Siberian sled dogs – can reach much higher levels. But there’s also going to be a big improvement in your fat-to-muscle ratio with regular bouts of HIT. In the Catalyst episode, the reporter took a DEXA body composition scan to measure this ratio. It also measures bone density. DEXA stands for Dual Energy X-ray Absorptiometry, that means you’re subjected to 10 minutes of very low-dose x-radiation at two different energy levels. It measures the relative densities of the different tissues. You can get this scan done in Adelaide, for a baseline measure, but it’ll probably cost an arm and a leg.

Jacinta: One way to lose weight. Cheaper to just take it for granted that you’re getting more muscular with every HIT.

Canto: Spoken like a true scientist. But generally, inactivity itself is a health problem, and anything that raises your metabolism, as HIT most definitely does, will be good for you, if it doesn’t kill you. And of course one of the most exciting findings in recent times is that your VO2 Max can be raised, with all the associated health benefits, without spending crazy amounts of time and money at the gym.

Jacinta: So how did they make this discovery?

Canto: Well I suppose they were doing a lot of experimenting and testing around the health benefits of exercise, but one test, a Wingate test, involved 30 seconds of all-out pedalling on an exercise bike, repeated a few times between periods of rest, to make up to two or three minutes of full-on exercise per session.

Jacinta: And this was for already-athletic types, right?

Canto: Yes – not advisable for middle-aged or post-middle-aged couch potatoes to start on that regimen. I’m currently doing three fifteen-second bursts, building up to 20-second bursts, then up to 30 seconds and no more. So researchers found that endurance levels can be dramatically improved after just six minutes or so of this kind of exercise. A doubling of endurance capacity, no less. Compare this to the current recommendations of 150 minutes a week. Who ever does that, apart from gym junkies?

Jacinta: So, it’s like this incredible short-cut to health.

Canto: Well of course it isn’t the solution to all ills, but among other things such a quick turn-around is a great motivator towards a healthier lifestyle all round. And it doesn’t have to be an exercise bike – you can adapt it, for example you can get yourself outside and do interspersed 30-second sprints, but I hate running and I’ve got a gammy knee so I’ll stay on the bike.

Jacinta: So, have they looked more into the actual science of this? What’s happening here?

Canto: Well again it seems to be about sucking in oxygen and providing a drug hit to the mitochondria. They did this rather nasty experiment with mice, genetically modifying them so that their mitochondrial DNA wasn’t functioning properly – their mitochondria were getting worn out. They looked pretty sorry-looking compared to the control mice, prematurely ageing as evidenced in their fur, their neural activity, heart function and sensory abilities. Their life-span was about half that of normal mice, and no drugs improved the situation.  Then they set them on a treadmill regularly, 3 times a week, at a brisk pace, for 45 minutes each session, which you might think would’ve killed them off all the more quickly, but the result was a spectacular improvement in mitochondria production and overall health and energy levels.

Jacinta: And this was in genetically modified mice?

Canto: Apparently so. The program didn’t go into detail about that, except to say that the bad mitochondria were apparently being selected against. Now of course we’re talking about mice here, and this was looking at endurance fitness rather than HIT, but it’s been shown that HIT does all the right things, and in some areas performs better than endurance training. Reductions in blood pressure, improvements in insulin sensitivity, in muscle to fat ratio, in VO2 max all in a matter of weeks, but the really interesting finding was that with HIT, improvement in mitochondrial function was significant – which wasn’t the case after endurance training.

Jacinta: How do they know that?

Canto: They took muscle samples and measured the ability of the muscles to produce oxygen – basically a measure of mitochondrial function. After just four weeks of HIT, mitochondrial function improved by up to 30%, while endurance training over the same period showed little or no change.

Jacinta: Wow. Doesn’t say much for endurance training.

Canto: Well endurance training does improve your VO2 max and it’s hardly bad for you. But the thing with these quick sprints is the difference at the muscle level. Sports medicine distinguishes between fast-twitch, slow-twitch and intermediate muscle fibres. HIT uses a wider range of muscles and muscle types than endurance work, and that seems to be the key. Improvement in mitochondrial function confers a heap of benefits, so this kind of exercise wards off neurological and other conditions, including muscle weakness and epidermal deterioration, the tell-tale signs of ageing. In fact all exercise does this. Ever heard of the stratum corneum?

Jacinta: Mmmm, corneum, cornea, isn’t that part of the eye?

Canto: Excellent guess but wrong in this case. The stratum corneum is the top layer of the epidermis, the skin. It starts to thicken as you age, and the layer underneath gets thinner as your mitochondrial function reduces. You can slow down that process quite significantly with regular exercise. They did skin biopsies of sedentary people over 65 before and after endurance training. After just 3 months the skin showed great improvement – a 20 to 30 ‘youthening effect’, according to one researcher. The dead outer layer thinned, and the dermis, full of collagen fibres, thickened. So, clearly, you’re never too old to start.

Jacinta: Or never too young. So okay I’ll start.

Canto: Great, but let me describe one more impressive study, being done on menopausal women using HIT. Menopause is about a major decline in estrogen, which has serious vascular, heart and metabolic effects, as well as insulin resistance. You tend to produce a lot of bad visceral fat which negatively affects the liver, due to the over-production of cytokines – but that’s another story. Anyway, the women were given a sprint regime, of just a short period of fast peddling interspersed with more relaxing peddling, amounting to eight minutes of fast but not hard exercise all up. The results of this research haven’t been published yet, but the women’s self-reporting is all very positive, which isn’t surprising. The research is also based on previous research with obese young men, and the exercise proved very effective. Visceral fat is generally much easier to reduce than subcutaneous fat.

Jacinta: Okay, so we’re going to do this?

Canto: Absolutely. And finally, here are some links.

 

The Catalyst episode, http://www.abc.net.au/catalyst/stories/4319131.htm

http://www.tabataprotocol.com

https://newsroom.unsw.edu.au/news/health/sprint-fight-fat

High-Intensity Training and Changes in Muscle Fiber, [www.springerlink.com/content/1137px7x66667132]

Written by stewart henderson

October 16, 2015 at 8:34 am

the low-down on antioxidants

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forget ORAC, just eat them coz they look so yummy

forget ORAC, just eat them coz they look so yummy

I’m going to risk alienating other colleagues here, but this post follows on from the last set in being inspired by work conversations, this time about plants and antioxidants. A plant was brought in by a staffer who apparently dabbles in naturopathy on the side, and its antioxidant properties were extolled. What do I know about antioxidants? Very little, except that some years ago red wine and various berries were being sold to us as containing life-enhancing quantities of these good molecules or whatever they are. It had something to do with binding to and neutralising ‘bad’ free radicals in our bodies. Of course I had no idea what free radicals were. Then later, via the Skeptics’ Guide to the Universe and other sources, I heard that the experts were back-tracking heavily on these life-enhancing properties.

So, what with being told in the staff room that antioxidants could cure cancer or some such thing, while elsewhere hearing that they’ve been wildly over-hyped, I’ve been considering for some time that I should do a post on these beasties, for dummies like me.

As usual, the first thing that greets me when I attempt to research this kind of thing is the pile of propadandist rubbish you have to wade through in order to find bona fide, science-based info sites. The good thing is that, over time, you get quicker at dodging bullshit.

I immediately homed in on a link saying ‘beware of antioxidant claims’, as being right up my alley. It took me to the ‘Berkeley Wellness‘ site out of the University of California. There I’m given the first definition – that an antioxidant is ‘a substance that helps mop up cell-damaging substances known as free radicals’, which leaves me hardly the wiser. I’m also told that selling products with claimed antioxidant properties is real big business in the US.

I’m also introduced to the ORAC (oxygen radical absorbance capacity) concept. My neighbour has an ORAC diet book and I’ve wondered what it meant. It seems that in the USA there’s a trend towards advertising the ‘antioxidant power’ of products based on ORAC scores – 7,300 ORAC units per 100 grams for a certain cereal, for example, or 6000 ORACs for a pack of corn chips. Are these numbers reliable, and what do they mean exactly?

Not much, apparently. The fact is that antioxidant interactions in the body are extremely complex and little understood. ORAC is only one of a number of different antioxidant tests used by different scientists in different labs, and even when they use the same test, such as ORAC, different labs come up with widely different results. Let me quote the Berkeley site directly:

Moreover, ORAC and other tests measure antioxidant capacity of substances only in test tubes. How well the antioxidants suppress oxidation and protect against free radicals in people is pretty much anyone’s guess.

A lot can happen to antioxidants once a food is digested and metabolized in the body, and little is known about their interactions. What has high antioxidant activity in a test tube may end up having little or no effect in the body. Preliminary research has found that when people eat high-ORAC foods, their blood antioxidant levels rise, but such results still don’t prove that this translates into actual health benefits.

The article ends with the usual smart advice. Choose a balanced diet, don’t eat too much, not too heavy on the meat, and with a fair quantity of whole grains, nuts and legumes, fresh fruit and veg, and you’ll get all the antioxidants and other nutrients you need. Actually, this article from I fucking love science, which gathers together expert advice on avoiding cancers, covers it all – keep your weight down, keep to the above-mentioned diet, exercise regularly in moderation, watch the sugar and salt intake and usually she’ll be right, whether it’s cancer, heart disease or whatever.

Not much more to say, really. But no doubt a lot more can be said about the science, and I’ll say just a bit about it here. Antioxidants, as the name suggests, are compounds that reduce oxidation in the body. Free radicals – unstable molecules – are produced when oxygen is metabolised. Free radicals remove electrons from other molecules, damaging DNA and other cellular material. They’re necessary for the body to function, but an overload can cause serious problems, and that’s where a common-sense diet comes in – though there are other factors which can bring about an overload, including stress, pollution, smoking (pollution by another name), sunlight and alcohol. Everything counts in large amounts.

Antioxidants come in many varieties. Nutrient antioxidants found in a variety of foods include vitamins A, C and E, as well as copper, zinc and selenium. Non-nutrient antioxidants, believed it have even greater effects (raising antioxidant levels), include phytochemical such as lycopene in tomatoes, and anthocyanins, found in blueberries and cranberries. I can’t find any clear info on the difference between non-nutrient and nutrient antioxidants, and it doesn’t appear to be important. There is, of course, a lot of ongoing research on all of this, and it would be easy to get obsessed with it all, raising your stress levels and sending those free radicals zinging through your body in legions. And if that’s what you want, why not buy this book, for a small fortune, and find out all that we currently know about how frying food affects its nutritive value, with particular attention to antioxidants. Of course, by the time you’ve finished it, it’ll likely be out of date.

There’s a ton of material out there on antioxidants, but Wikipedia is an excellent place to start, and to finish. One key piece of advice, in this as with other matters of diet, is – don’t rely on supplements when you can simply improve your diet (recent large-scale trials have shown they don’t work anyway). Get what you need from real food, as far as you can.

Written by stewart henderson

February 1, 2015 at 9:52 pm

exercise is medicine

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I read recently that regular moderate exercise sloshes up the blood, washing immune cells from vessel walls. This brings those cells back into the mainstream so to speak, where they can be more effective in combating infection. It makes no small difference – a simple study in which 500 adults were tracked for 12 weeks found that those who engaged in regular aerobic exercise sessions were found to suffer considerably less from upper respiratory tract infections – precisely my personal area of concern. Levels of immune cells in the blood double during exercise.

There’s also good news in this for those of us who couldn’t become gym junkies no matter how hard we tried. Too much exercise (but that means quite a lot) can undo all the good by raising levels of cortisol, noradrenaline and other stress hormones, which alter immune cell functioning. Stress, though, is another one of those complex indicators of health. Mild bouts of stress can be healthful, again boosting blood levels of immune cells. So don’t relax too much, but don’t overdo it.

Even so, exercise helps with everything, and that’s something worth promoting because the recommended dose of exercise isn’t being swallowed by the majority of people in the west. Of course we’ve always kind of known about the benefits of exercise, but the hard evidence has really been coming in lately. A really interesting study was published in the Lancet in 1953, at a time when the rising incidence of heart attacks was becoming a worry. It compared bus conductors to bus drivers on London’s busy double-deckers. The conductors, who spent much of their working day running up and down steps, had half as many heart attacks as their driver colleagues. This landmark study has of course been followed by many others that have confirmed the positive effects of exercise in reducing the incidence of stroke, cancer, diabetes, liver and kidney disease, osteoporosis, dementia and d barkepression.

So what exactly is the goldilocks zone for exercise? Well, anything is better than nothing, and most of us know we’re not doing enough. I’m not quite a senior citizen yet, but studies have been done with the elderly requiring them to do 40 minute walks three times a week, which is hardly strenuous. I catch a tram to work, which requires a ten-minute walk each way, and then a five minute walk each way to my workplace – 30 minutes a day, five days a week, though it would doubtless be better if those 30 minutes were continuous, and if I didn’t dawdle much of the time. The benefits of such a regime have been shown through before-and-after brain imaging. Expansion of the hippocampi, either through the growth of new brain cells, or greater synaptic connectivity, and a restoration of long-distance connections across the brain.

Mental exercise shouldn’t be forgotten either. It has been known for a couple of decades that intellectual stimulation can provide a kind of ‘cognitive reserve’ which can buffer us against the kinds of physical brain deterioration typical of Alzheimer’s and other forms of dementia, but clearer proofs of this have been gathered recently. Magnetic resonance imaging of Alzheimer’s sufferers has caught the goings-on in the brain while cognitive tasks are being performed. Highly educated people – brain workers  if you will – are better able to develop alternative neuronal networks to compensate for damaged areas. I would assume though that it’s not so much about education but about brain usage. Keep tackling new things. Keep using your brain in new ways. And your body for that matter.

Cognitive reserve is now seen as a real thing, and has been pinpointed as residing in the dorsolateral prefrontal cortex, a key area for learning, short term memory, attention and language. Increased activity in this area suggests flexibility in thinking and problem solving. Information processing efficiency is also a key to a healthy brain. Having a high IQ, something I’ve often been sceptical about in the past, is an indication of information processing efficiency, even if the information is often culturally specific. It appears that physical brain deterioration, from Alzheimer’s, stroke and and other causes, can be fended off by compensating neural network development and increased information processing efficiency in certain people, until the deterioration becomes too great to be compensated for, after which things tend to go downhill very rapidly. By the time the symptoms of Alzheimer’s appear in such people, the  physical damage is already well advanced.

A major message from all this is that you should try to develop lifestyle habits involving physical and mental exercise. Always a work in progress.

I note that one of the in terms these days is ‘hat tip’ (h/t), so h/t for this piece to New Scientist, the collection, edition 3: a guide to a better you.

Written by stewart henderson

November 20, 2014 at 8:19 am

Posted in diet, exercise, fitness, lifestyle

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can your shoes help you run faster?

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time to ditch your adidas microbounce plus trainers for neutral to underpronating runners, with lightweight heel-to-toe bounce technology, etc etc - it's all just a load of expensive shite unless you're deeply into the status doo-doo

time to ditch your adidas microbounce plus trainers for neutral to underpronating runners, with lightweight heel-to-toe bounce technology, etc etc – it’s all just a load of expensive shite unless you’re deeply into the status doo-doo

Some years ago, when I was a bit more financially solvent than I am these days, I went to a gym for a while, and even employed a personal trainer. I learned from that experience, thanks to some simple exercises the trainer put me through, and my own quick development through these exercises, that, once I’d gotten this kick start, I didn’t need the expense of a gym, or a personal trainer for that matter, which is just as well, as I soon went broke and abandoned both.

Since then I’ve been using a combo of my trainer’s tips and some CSIRO-recommended exercises to stay moderately in shape at home, happily far from the sight of buffed-up men hefting obscene weights, not to mention bubble-butted women with sweat sparkling from their flawless sun-tinted flesh..

Anyway, one of the things that sometimes worried me when I turned up for gym was my footwear. I noticed that most of the inhabitants wore all the ‘right’ gear including what looked like the latest state-of-the-art top-brand ‘gym shoes’ or running shoes or whatever. I wore a pair of $10 canvas slip-ons, and I always expected the trainer to query them, though I’d also heard or read somewhere that all these expensive ‘scientifically tested’ exercise shoes were a load of malarkey, and you’re possibly better off with good old-fashioned plimsolls, or even nothing at all…

So it was with some interest that I listened to a little segment on a recent science show podcast, dealing precisely with this subject. An English researcher, Mick Wilkinson, who’s also a keen amateur runner, has been looking at running barefoot v running shod, and he ran a half-marathon barefoot in 2011 just to test things out. He came out of it more or less unscathed in spite of some less than barefoot-friendly surfaces.

As to the evidence, much of it was a summary of what a Professor Lieberman of Harvard has found, findings published in Nature and a recent issue of New Scientist. Basically, Lieberman has found that we are born – that’s to say, evolutionarily adapted – to run, considering our skeleton and muscles, and issues of endurance and heat loss (the latter being an obvious consideration in going barefoot). An analysis of ‘peak impact forces and the rate at which those forces are absorbed by the body’ indicates that barefoot running, because it favours a ‘forefoot landing’, a type of foot strike pattern that’s associated with ‘a lower loading rate’ (presumably meaning less overall pressure), is less jarring than its alternative.

Looking at joint movements and rotational forces around the ankles and the knees, the evidence is that, with barefoot running, forces around the ankles are increased, forces around the knees are decreased. This is very interesting to me, as I stopped jogging years ago because one of my knees would stiffen up every time I did it. I was running in fairly basic running shoes, but more importantly to my mind I was running on a hard gravel track. Years later when I did a bit of jogging on grass I didn’t have a problem. Generally though I hate jogging and much prefer cycling, with a nice café at the end.

But what about the effect on the ankles? According to Lieberman the evolution of structures on the rear of the leg, the Achilles, the calf and the soleus (a powerful muscle in the lower calf) have generally evolved to cope with these stresses on the ankle region. More research needs to be done, but there are some pretty serious difficulties, as Wilkinson points out:

So we’ve got biomechanical aspects linking forces, we know that forces are theoretically linked to some kinds of injuries, but that’s where it stops. What is missing is the next piece of the puzzle which would be the randomised control prospective studies examining injury rates in people who are learning to run barefoot, people who are learning to run in shoes. But the design of the study would be so complex, it would be prohibitive. I mean, you’d have to get people who were matched for training history, matched for age, matched for injury status. In fact it would probably be better to start off with people who had never run at all and just say, right, randomly allocate you into a group who are going to learn to run in shoes, you’re going to learn to run barefoot, and then track them over a very long period of time to find out what injury rates are per so many thousand miles. But again, it’s so difficult to operationalise a study like that, probably why one hasn’t been done.

In any case these studies wouldn’t so much answer the question of whether you run faster in shoes, as whether you run better – that’s to say, with less general impact on the body. It, not quite the same thing, though they are connected. And obviously there are hazards in running barefoot in modern urban environments. But there doesn’t seem to be much evidence to support all the advertising claptrap trying to get you to buy ultra-expensive running shoes. In fact, there’s been little noticeable difference in times for running marathons – the real test for shoes v bare feet – in spite of, not only high-tech footwear but all the other-high tech analysis in terms of diet, running technique and so forth. Wilkinson tells us that the American distance runner Steve Prefontaine still holds the American marathon record from the early seventies (Prefontaine was killed in a car crash in 1975, aged 24), and he always wore a standard pair of plimsolls.

So it looks like another case of advertising, and dare I say pseudo-science, winning out over the evidence..

Written by stewart henderson

October 1, 2013 at 12:01 pm

exercise, health, skepticism and my personal journey

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benefits-of-exercise-2

‘Many of the most important benefits of exercise lie hidden deep inside your body.’ Michael Mosley

When it comes to diet and exercise, everyone seems to be an expert, and even a crank, to judge from many of the comments left on the SBS on demand site for its recent doco, ‘The Truth about Exercise’, presented by Michael Mosley. A scarily large number of these comments are of the ‘that’s all garbage, now I’ll give you the real lowdown’ variety.

And yet, considering how unique each person’s body and its requirements seems to be, maybe it’s not so surprising that general claims get up the noses of so many particular people.

So it’s good to be sceptical, though I was a bit surprised at the degree of scepticism about this doco when the subject came up recently – admittedly at a sceptics’ meet-up. So I’ve decided to take a closer look.

The program looked at a variety of surprising research findings, indicating, among other things, that your genes determine to a large degree whether intensive exercise will confer a benefit. There’s also controversial and counter-intuitive evidence that infrequent, sharp bursts of exercise, which get the heartbeat up and briefly racing, can provide a greater benefit than regular daily gym exercise. Offhand, I can think of an evolutionary basis for this finding, in that we evolved to combine a relatively indolent, social lifestyle with occasional energetic bursts to catch prey or run from predators. But what would I know?

Early on, we’re given a simple and salutary lesson about exercise and weight loss. Mosley, the program’s host and chief guinea pig, is monitored by a respiratory device on a relatively gentle [6mph] run around a training track. The device measures the amount of oxygen and carbon dioxide exhaled. Looking at the ratio between the two gases enables us to estimate the amount of fat and carbohydrate, or calories, being burned, apparently.

Mosley was measured as burning some 16 calories per minute during his run. It was then pointed out to him that, at that rate, it would take him 55 minutes to burn off the calories consumed in a cappuccino and a blueberry muffin [which he proceeded to consume after his run], plus a banana. Sounds like bad news.

Some questions about this. How close to average is Mosley’s calorie-burning level at a speed of 6mph? If I did the same run, would I burn off more calories, or less? A lot more? A lot less? How wide is the range? And do you burn off less calories if you’re much fitter? How much less?

The basic lesson here, though, is, if you want to lose weight, eat less. Exercise isn’t likely to do it for you, but it will certainly confer other benefits.

The next section of the program looks at fat levels in the blood. Mosley is treated to a hearty Glasgow breakfast of baked beans, sausage, bacon, black pudding [I think], some sort of creamed egg concoction [I think] and toast. As we’re told, the fat in this meal will be processed though the gut into the bloodstream, inducing metabolic processes which will determine the amount of fatty deposits forming on the walls of the blood vessels.

Four hours after the breakfast, a blood sample is taken and placed in a centrifuge to separate out the fat. This is compared to a blood sample taken before the breakfast, and we see that the amount of fat in the post-breakfast sample is about double the pre-breakfast one. Note that this is one sample – double the amount in the whole bloodstream, and you’re talking quite a load of fat.

As the Glasgow researcher, Dr Jason Gill, points out though, a key factor here is where this fat ends up. Sub-cutaneous fat is much less damaging than visceral fat, fat around organs such as the liver and pancreas. Unfortunately, many of us, like myself, don’t know where our fat is going, or what percentage of visceral fat we have. Mosley does know, however, that his percentage of visceral, or abdominal fat is disturbingly high. A high load of this kind of fat makes you susceptible to insulin resistance and type 2 diabetes and other problems. Mosley’s father suffered from type 2 diabetes, adding to his disturbance. How much of a part do your genes play here?

Mosley is given another big Glasgow breakfast the next morning, but this time he takes a long but seemingly leisurely walk the night before (Mosley describes it, though, as ’90 minutes of pretty hard walking’). This walk should have triggered the production of an enzyme that in turn should affect the way this second breakfast is metabolized.

Again, Mosley is blood-tested four hours later, and although the interaction is a bit confusing to me here, it seems that the sample this time contains about a third less fat than the one the day before.

More questions. We don’t know what Mosley did the night before he had his first breakfast, so we can’t compare it to the exercise of the night before his second breakfast. We also don’t know, on either occasion, what he did in the four hours between eating his breakfast and being tested.

In any case the fat in the blood vessels has substantially reduced, because it has been taken up into the muscles where it will be mostly burned off.

This is a remarkable finding, and the key enzyme or protein is lipoprotein lipase, or LPL. But most people would begrudge, or simply not have time for, 90 minutes of solid, swift walking of an evening. Any alternatives?

Well, British government guidelines make a general case for 150 minutes of moderate exercise per week, or 75 minutes of more vigorous exercise – and, unsurprisingly, most of us don’t manage this.

So, Mosley visits Prof Jamie Timmons in Nottingham whose team is looking at exercise differently, seeking to fit exercise regimes to particular individual needs. These researchers are looking at the wide variation of response to and benefit from exercise. They conducted a four-year study with a thousand subjects who exercised 4 hours a week for 20 weeks. Not surprisingly, average fitness improved, but it was the variation within the range that was the focus of the research. They found a spectrum with about 15% being ‘super-responders’, and about 20% at the other end recording ‘no change’. From this research [obviously there’s quite a bit of science missing from the explanation here] they were able to isolate 11 genes. This has further enabled them to devise a genetic test to determine which group a person belongs to, or where he sits on the spectrum.

More questions. So what if you’re one of the no-change types – is there really no benefit at all for them from this exercise schedule? That sounds almost crazy. And if this doesn’t have any effect, what will? The program doesn’t quite deal with this issue. Mosley states that the non-responders will benefit [which is essentially contradictory] but doesn’t say how. Which leads to the question – what exactly is being measured here? Obviously, a response to exercise, but what kind of response? Weight loss? Changed metabolism? Conversion of fat to muscle? Blood sugar levels, blood lipid levels? Sense of well-being?

Presumably it’s a combination of these elements, but the general point is clear – presenting benefits by means of averages doesn’t really help the individual, considering the massive individual variation revealed by this and other studies.

Personalised medicine and personalised exercise based on genetics may be the way of the future, but I wonder how easy, and how expensive it would be for each of us to access our genetic profiles. Of course the host of our program has no problems with that because he gets his genetic tests paid for presumably by the BBC.

Mosley is also tested for a couple of other things. First, he’s given a sugary drink (presumably glucose not fructose – the difference between these two sugars has become something of a dietary issue lately) to measure his insulin sensitivity. Insulin removes sugar and controls fat in the blood, and if there’s a problem with its production or activity you can become diabetic. After the drink, Mosley has his blood regularly examined to determine how effectively his insulin is doing its job. As it turns out, his results are not so good – the blood-sugar level shot up after the drink of course, but it drifted down only slowly to a point just below ‘impaired glucose tolerance’, putting him only just in the healthy range. The plan is to introduce him, and us, to some exercise that might improve his situation.

Before that, though, he has to undergo his second test, to check out his aerobic fitness, also known as VO2 max, with V standing for volume and O2 for oxygen. In other words, maximum or peak oxygen uptake and capacity.

Perhaps amazingly I’ve never heard of VO2 max before, in my fifty-odd years on this planet, but it’s probably all the rage amongst modern-day gym junkies. It’s a measure of heart and lung efficiency at getting oxygen pumping through the body. It’s not really clear what the number measured indicates, but it correlates pretty well with general fitness. The number for Mosley was 37mls per kg, after scaling for body weight. Top athletes get up to 75, and the much less fit are down in the twenties. As someone who’s become quite interested in weight loss, exercise and fitness recently, I’d be very interested to discover my own VO2 max, but as the program shows, people are put through a punishing exercise test to determine the number, which itself could be quite dangerous, if you’re elderly or have heart issues. So this is an issue I’ll come back to as I try to get more info on myself.

After these tests, Mosley’s introduced to the high intensity training (HIT) protocol, which represents one of the most exciting and controversial developments in ‘exercise science’, if there is such a thing. On an exercise bike, he’s asked to do three short (20 second) bursts of give-it-all-you’ve-got cycling, with rests in between. That’s a minute of HIT, to be undertaken 3 times a week – so, 3 minutes a week. Not worth going to the gym for. Actually the principal attraction the gym held for me, during the short period when I regularly attended, was the sight of athletically lissom females. Sadly, I got rid of my exercise bike, reluctantly, a couple of years ago. Now I’ll have to buy another, because I’m definitely keen on this HIT stuff.

So why does HIT work? The science isn’t clear, but it definitely does work, as shown by many labs around the world. This HIT regime is enough to break down the glycogen stores in the muscles – the store of glucose. This is a key signal from the muscle to the bloodstream saying ‘I need more glucose’, which presumably results in the sugars, the calories being sucked out of the blood into the muscular tissue. This sort of thing happens on a low level with any activity, such as simply walking, but HIT sends out this message from a far higher percentage of the muscle tissue than walking or other mild activities. So for those at risk of diabetes, HIT appears to be an excellent approach

HIT is also good for increasing your VO2 max, presumably because it primes the body to expect, every now and then, short sharp bursts of intense effort, as our evolutionary development might have done. As the researcher says, the sense, after only 20 seconds, that you’ve engaged in a thorough-going, lung-bursting, heart-pumping workout, is a good indication of the VO2 max benefits. The benefits of HIT are not immediate, but after about six weeks the effects should become clear.

So Mosley commits to trying HIT for a month or two, and in the meantime he checks out some more research, this time on NEAT, another low-cost, no gym fees way of keeping healthy. NEAT stands for Non-Exercise Activity Thermogenesis, a neat acronym for avoiding sitting around on your butt all day, which many people spend twelve hours or more a day doing. NEAT basically means  the calories you burn in all your everyday activity and movement, apart from deliberate exercise, whether inside or outside a gym.

Mosley is asked by James Levine, of the Mayo Clinic, to put on a pair of ‘fidget pants’ or NEAT underwear, which are ‘wired up’ to register all daily, and nightly, movements. A bit embarrassing, thinks I, if you’re known to sleep alone and you register some suspicious nocturnal rhythms, but hey, if it keeps you healthy… In fact doctors recommend…

The point is that just about any activity will increase your metabolic rate – though I’m a bit sceptical of the numbers Levine throws around here – ‘this guy’s walking slowly, about 1mph, that’s okay though, he’s doubling his metabolic rate, and look that guy’s walking twice as fast, so he’s tripling his metabolic rate..’ Really? Sounds like this is based on averages again, and even at that, I doubt if just doubling your walking speed doubles your metabolic rate. But hey, picky picky, it’s surely all doing some good.

Mosley and two other subjects are to have their daily activities tested via the pants. One works in a busy cafe, the other is a writer, particularly on health issues, who goes regularly to the gym.

The three subjects are measured over a 24-hour period, and the results are presented a bit sketchily – a problem with cramming so much in in an hour-long doco. The cafe worker is described as gold medal material from a NEAT perspective, because she’s constantly active, as her graph shows – but in fact only in the morning. There follows a period of complete inactivity according to the graph, but this doesn’t get a mention. The health writer’s graph is sporadic, with occasional bursts of high-level activity, including a very fast and reasonably long walk from one building to another, which Levine doesn’t seem much impressed by (he simply says at the end that the cafe worker produced impressive NEAT results, while the other two failed, essentially). Mosley’s own results indicated regular but quite low-level movement, which didn’t add up to much. So he did an extra 24-hour session with the fidget pants, this time making a concerted effort to sit less, and to generally be more on the move. Levine tells him that his much-improved graph means that he’s burned off 500 calories more than in the first session, so potentially he could be burning off 500 calories daily.

Scepticism time again. The 500 calories thing is again based on an average. Metabolism varies enormously, and if it’s true that there are super-responders and no-changers when it comes to gym exercise, why wouldn’t it be true for NEAT activity? Also, is it really about calories?

Well, Levine answers that last question, sort of, in the next segment. Regular movement just keeps the system going, in terms of blood sugar and blood lipid levels and various other indicators, in a way that long sedentary hours, followed by a burst of activity, even at a gym, doesn’t. At least that’s what recent research seems to be telling us. It’s the sedentariness, according to Levine, that seems to be ‘the killer’. Sitting around in a chair all day is killing millions, is his stark assessment.

So Mosley continues on his journey among the researchers, while working on his HIT, and improving his NEAT. His next stop is the University of Brighton, where Dr Emma Ross is working on brain activity and fatigue. Mosley is asked to do some cycling in a hypoxic chamber, where the oxygen level is lowered (these are the in thing for pro distance cyclists, who often have to compete at altitude). The chamber shows a 14.2% oxygen level, compared to 21% outside the chamber. The idea is raise the fatigue level more quickly, but also the ‘brain concern level’, if you will. Mosley lasts only a few minutes. The oxygen saturation in his blood drops to 82% – presumably from 100%? The significance of this figure, and its effects, aren’t explained. Immediately afterward, he’s strapped into a chair, has electrodes placed on his thighs and has his leg strapped with a strain guage, to measure his kick strength. First he’s asked to push his muscles as hard as he can, then a trans-cranial pulse is attached to his head. This delivers a magnetic pulse to his leg, and the result of all this isn’t too easy to follow, but it seems as if the brain is communicating with the muscles and telling them not to strain so hard. That’s to say, the brain seems to be in ‘somewhat concerned’ mode, creating a safety margin for your exertion, which can be reduced through awareness and training. By reducing that safety margin, you can improve your overall fitness and health benefit.

We’re nearing the end. Mosley returns to Nottingham to see how his HIT schedule has worked out – though there’s a slight problem, as one expert has noted, in that Mosley has confounded the results by engaging in NEAT and other fitness experiments in the interim. This would tend to enhance the findings.

Never mind, it’s all good, and Mosley found that his insulin efficiency had improved by 23% since his previous test. So it seems that, with a combination of HIT and NEAT, you can’t lose…. Except that the test on Mosley’s aerobic capacity revealed no change, and this was in keeping with his genetic test. So, as the program concluded, good for science, bad for Mosley, at least so far as his VO2 max was concerned.

So my overall view of the program was that the science was persuasive, and quite exciting, especially re the ‘HIT protocol’.

On a personal level I find this very interesting, and in tune with my intuitions. When I was young I was a skinny thing who had little interest in food, in fact I actively disliked most of it, and my mother despaired of finding any kind of food I liked. In my teen years I was quite sporty and active but I hated exercise. I loved sport for the competition, not the exercise. In my early twenties I worked for a few years in a really good restaurant and discovered the joys of food and cooking, but I still quite active and sporty and rode a bike everywhere, but as the twenties moved into the thirties, sport became less of an activity and more of a spectacle, and I got my driver’s licence and could afford to eat out more, and my weight, as I got into my forties, began to creep up. In my teens and twenties I was around 69 or 70 kilos, just within the normal rate for my height (168cm), according to the BMI. In my thirties and early forties this crept up to the low to mid 70s, and then in the late forties it started to climb a bit alarmingly, reaching a maximum of 83.4 – that’s about a kilo below the obese range – in November -December last year. It’s probably fair to say that in the ten years leading up to that high, I’d exercised very little.

This morning, after a year, not of dieting, but of eating less and exercising a bit more – regular walking and some simple, non-strenuous CSIRO exercises, my weight was 72.9 and falling. I actually allow myself to feel hungry and quite enjoy it. I try to get back to the mindset of my youth when food didn’t matter to me. It’s not easy but it does work for periods. I also feel the benefits. I was over-eating and suffering gastric and digestive problems. They’ve disappeared this year.

So, although it’s unlikely that I’ll get genetically tested for my response to exercise – unless the test becomes freely available in the foreseeable – my guess is that I’m closer along the spectrum to the super responders than to the no-changers.

I also find the NEAT results are in keeping with my personal intuitions. As I got older and stopped playing sports, I became conscious of the dangers of sitting around all day. I’m a big reader, and a regular writer, so obviously sitting has played a big part in my whole adult life. When I lived alone, I used to read while pacing about in my flat. Nowadays, with podcasts, I can time a solid evening walk with a 70 minute or so episode of the SGU. When I visited people, I got mild complaints that I wouldn’t ‘sit and relax’, but preferred to chat while on my feet. That was more in my forties (I’m now 56). In recent years, before 2012, I kind of gave up, and relaxed into pudgy middle age. But 2012 has brought a change, in my dietary and activity habits, and it’s been all to the good. I’m only two and a half kilos from being out of the overweight range and into the normal range. Ultimately my aim is to get down to under 70ks again, perhaps for the first time in 30 years, and I’m on target to achieve that. Importantly, without strain. I’m aiming for a kilo a month, so my target is to be below 72ks by the end of January, and below 70ks by the end of March.

Written by stewart henderson

January 1, 2013 at 10:30 am