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‘Rise above yourself and grasp the world’ Archimedes – attribution

exercise, health, skepticism and my personal journey

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‘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

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