Is Aerobic Exercise a waste of time?

A recent report published in the Journal of Applied Physiology reports that the health benefits of aerobic exercise are determined by our genes. They found that 20% of the people in their study improved their aerobic fitness by less than 5% and that in 30% of people it had no difference on their insulin sensitivity.

The press obviously jumped on this and ran all kinds of headlines saying Aerobic exercise is a waste of time. I thought I'd do a bit of research to find out exactly what this all means.


With any study you need to look at exactly what was studied and what was measured, in this case the aerobic exercise the participants undertook was vigorous exercise for 30 minutes five times per week. Now after the study was finished 80% of people showed a significant increase in their aerobic fitness but 20% showed an improvement of less than 5%

Two things to consider here. First of all 30 minutes of vigorous exercise is one of the least effective ways to increase your fitness. Any fitness professional will tell you that doing 30 minutes as hard as you can is a particularly ineffective way to increase your fitness. Interval training has be shown to be a far more effective training method.

The other factor is how did the scientists determine if the participants had improved their fitness? In this case they measured the VO2max of each person before and after the study. It is well known that VO2max (the maximum amount of oxygen a persons body can process)has a large genetic component. It is estimated ( depending on what study you read) that you can improve your VO2max by around 10-20%. People who are already fit will find it much harder to improve as they have already used up some of their possible 10-20% improvement. Also consider that even the 20% of people who improved by less than 5% in the study they still improved and remember that VO2max can only be improved by 10-20% anyway so a 5% improvement is not to be ignored

I was unable to find the exact details of the participants in the study but one hopes that the people used had not been exercising regular before the study started otherwise they may have already improved their VO2max making more difficult to make any further improvements.

VO2max is not the be all and end all of aerobic fitness, it is still possible to increase your fitness without an increase in your VO2max by increasing the efficiency of your body when it performs that exercise.

So from a fitness point of view if you have an exercise program that in more than 80% of participants ( the other 20% improved but less than 5%) you see an improvement in aerobic fitness then I would say that actually proves aerobic exercise is not a waste of time.

To say that 20% do not receive any health benefit's at all is extremely misleading in a time when we should be encouraged to exercise , not given reason not to.

They also found that aerobic exercise did not increase insulin sensitivity in 30% of people. This is also very misleading. What they actually mean's is that if you perform 30 minutes of vigorous aerobic exercise 30% of people will not see an increase in their insulin sensitivity.

This doesn't mean that a long walk wont improve insulin sensitivity in those people or interval training wont improve it. They only tested one method of aerobic exercise.

What it does mean is that exercise professional's should give their clients a variety of different aerobic training regimes to maximise the chances of improving aerobic fitness and insulin sensitivity. What we shouldn't be doing is promoting the idea that some people wont have any benefit from aerobic exercise and should look to medication instead!