FIT FOR PURPOSE

Being fit for your age is of greater importance than being competitive, writes Norman

“A 60-year-old male with a VO2 max reading of 36 would be in good health. For women, it’s 30”

There you are, looking into the bathroom mirror, with a 60-year-old face staring back at you. You cycle regularly, watch your food and keep your mind active. Idle thoughts cross your mind - ‘When I hit 70, will I still be as healthy as I presently am? What criteria can I use to judge the changes in my status that have taken place over the decade?’ Off you go to see your local medical practitioner. Your blood pressure is taken, your eyes examined, blood sample given; your heart, lungs and pulse are all okay. Reflexes too. The verdict is that you’re in good health. Then your question is, ‘How does my health status compare to another exercising 60-year-old and what will my status be in 10 years’ time?’ The doctor shakes your hand and suggests some tranquillisers.

Is there an index we can use that’ll give us an overall indication of our health? Yes there is and it measures the ability of our bodies to supply oxygen when pushed. This index is known as VO2 max and is determined by the millilitres of oxygen used per kilogramme of weight in a minute. Or ml/kg/min. The ability to supply adequate oxygen under exercise is a great indicator of the health of many systems in the body. To supply oxygen efficiently, your heart, lungs, blood vessels, brain, muscles and many other systems need to be in tip-top form.

There are tables giving healthy VO2 max readings over the human age range. A 60-year-old male with a VO2 max reading of 36 would be in good health. For women, it’s 30. Obviously, you could make your VO2 max higher by going mad and pushing exercise levels to your maximum. Do not do that. You are presently doing sufficient exercise to likely be free from all the diseases that strike the sedentary. If you are a competitive person who wants to win at everything then that might be the way to go, but remember: there’s no data suggesting that you become healthier as you become more competitive. We define healthy as being free from those diseases that arise from being sedentary. Exercising beyond that level does not make you healthier. In terms of our definition you cannot be healthier than healthy. That makes no sense. You just become more adept at your discipline. For us oldies there is no need to overdo it. Just keep sensibly rolling along.

From ages 60 to 70, you keep all your good habits and take another VO2 max test. Now a healthy reading for men is 33ml/kg/min and for women 29. So, despite doing all the proper things, at 70 you wouldn’t be able to compete with your 60year-old self.

That said, you’re still as healthy as a 70-year-old should be but your physiology has shrunk. That is the ageing process at work. Both the 60-year-old and the 70-year-old are healthy. They do, however, occupy different levels of physical ability. No 70-year-old can hope to compete with someone 10 years younger provided they’re both exercising at equivalent intensities relative to their ages.

The great thought to hang on to is that you have escaped the diseases of ageing by sensible behaviour and are enjoying those final golden three decades of your ageing years. What about me? Well, if you consult most of the tables, they don’t have figures for 85-year-olds. I would guess when the tables were constructed there were not many of us about!

We’re attempting to correct that at King’s College by continuing research on ageing cyclists. I did have a VO2 max measured about 10 years ago. I came out at about 50ml/kg/min, but I was doing a lot of audax. That was the reason for that particular VO2 max reading. I’m sure I will be much lower now but so what? I’m also sure I will still have a measurement sufficiently high to be protected from the dangers of being sedentary, however the ageing process marches on.