IS EXERCISE THE HOLY GRAIL?—-This is a great documentary done by the BBC Horizon series
This is a must see documentary, an insight into the world of sport scientist and how exercise can lead to prolonged quality of life.
http://www.bbc.co.uk/programmes/b01cywtq
Like many, Michael Mosley want to get fitter and healthier but can’t face hours on the treadmill or trips to the gym. Help may be at hand.
He uncovers the surprising new research which suggests many of us could benefit from just three minutes of high intensity exercise a week.
He discovers the hidden power of simple activities like walking and fidgeting, and finds out why some of us don’t respond to exercise at all
Using himself as a guinea pig, Michael uncovers the surprising new research about exercise, that has the power to make us all live longer and healthier lives.
- As far as weight loss is concerned, unless you are running marathons every day, exercise will probably not counter a bad diet. If you want to lose weight, it’s all about the diet. The exercise is a bonus. For lots of people, as they increase their exercise they also eat more, probably because they think they can afford to. The classic, “It’s OK to have this because I’ve been to the gym today!”, line springs to mind.
- For insulin sensitivity, High Intensity Training (HIT) (or High Intensity Interval Training (HIIT)) training rules. The minimum you need to do to get significant benefits is 3×20 second bursts of all out effort, 3 times a week. That’s 3 minutes of hard exercise a week! So the workout the guy followed was, 20 seconds max effort on an exercise bike, followed by 2 minutes of slow peddling, then repeat that 2 more times. This workout was done 3 times a week. Compared to most HIT/HIIT/Tabata workouts, this is very easy, but if you are not used to interval training, this is actually a lot harder than it sounds. Max effort really does mean you peddle like your life depends on it!
- For aerobic fitness (VO2 max), the effect is less predictable because your results depend very much on your genetics. About 15% of people get sensational improvements in VO2 max. About 20% of people get no benefit. The rest scatter somewhere between the two groups. They have a genetic test to predict your reaction. It’s interesting/scary to know that your chances of improving your VO2 max, regardless of the exercise program used, is fixed from the point you are conceived. Assuming you are not one of the poor responders, this 3 minute a week HIT workout can give you most of the health benefits you expect to get from exercise.
http://www.bbc.co.uk/programmes/b01cywtq
2 Comments
Whilst it was a very interesting programe, the section on running / diet / weight loss was highly misleading.
When presented with the muffin / bananna / coffee and asked how long it would take to run off the calories, my guess was an hour. This was pretty accurate – I impressed myself.
However, what this shows, is what a huge number of calories there are in a muffin, not how little energy is expended by running.
The figure quoted in the programme was 16 calories every 1 min – this has to be put into context. Suppose someone ran for 30 min 4 days a week they would be expending 2240 calories through exercise every week.
This is a lot of enmergy expenditure and the programe was wrong to suggest otherwise.
Most people with no experience of sport / regular exercise find it hard to maintain any exercise regime that involves expending more that 2000 calories a week through exercise.
If we assume average calorific intake is ~2000 per day, even this quite modest exerise regime would be equivalent to followuing a diet of 1680 calories per day – which is quite a strict diet.
If this exercisse was properly maintained with no change to other activity, then the person will loose weight.
And there is the problem – maintaining with no change to other activities.
Other work, done at Glasgow University a long time ago now (John Durnin), looked at this issue. As the programme said, there is a tendency to compensate by eating more but, what seemed to be more important was that people who were not used to regular sport / exercise tended to spend longer period being inactive when they started an exercise programme.
To put it bluntly – they were so tired that they tended to use cars instead of walking, sit and watch the TV instead of hoovering etc. – these peroids of increased inactivity played a big role in offseting the benefits of exercise.
The other issue is that, even if weight does not change, exercise encourages the development of muscle.
If we develope 1 lb of extra leg muscle with no change in weight, then the muscle tissue must have come from somewhere – that somewhere is body fat.
Muscle has a higher metabolic weight than fat and so, even if they follow exactly the same pattern of daily activity, a person who is muscular will always expend more energy than a person of the same body weight who is fat. This has a very important consequence since, if they eat the same diet, the person who is muscular will find it easier to maintain his body weight whilst a fat person will tend to get fatter.
I am very skeptical of explanations based around genetics – these are statistical associations based on huge sample sizes and if you really look at the figures they are actually quite weak associations.
This is a broad sweeping generalisation I know, and it may well be that it does not apply in this case, but this is a blog not an academic review and that is my personal opinion.
When mendelian inheritance was first re-discoved, there was a very similar trend – people looked back through geneologies and tried to see if they could find any evidence for all sorts of things being inherited. My favorite is an extensive study of families that included sailors – this analysis showed that there must be a single identifiable gene for “wanderlust” and much time and effort was devoted to working out its pattern of inheritance.
New developments always promote new ways of thinking – but many of these new ways of thinking actually turn out to be wrong with the benefit of hindsight. Just because genes can explain diferences between groups, does not mean that variations in these genes must explain variability within groups. There are clearly identifiable groups who are prone to obesity (has anyone been to the pacific islands – you certainly see it there) and these do appear to be related to genotypes. This does not provide any evidence that variations in obesity within all ethnic groups.
This whole area goes through cycles – I can remember Rothwell and Stock’s nature paper which put forward the thermogenesis idea (1980 is?). The idea wasn’t new then but that paper stated a trend for that way of thinking – more recently there has been a lot more on appetite.
cool!