How does age affect your fitness?

How does ageing affect your fitness?
95 year old Ida Keeling running with her 60 year old daughter Shelley.

Let’s face it, from the moment we’re born, we’re marching steadily on towards the other end of our lives. Along that time line, we get stronger and fitter, until we reach a certain point when our fitness levels start to decline. It’s a fact, and there’s nothing we can do about it. Right?

Wrong! Well, kind of wrong. It’s true, as you age, you’ll experience a decline in your maximum exercise capacity.

Your capacity to recover quickly from long or intense bouts of physical activity will also decline, but you can do something about it.

How does age affect your fitness?

A number of  studies over the years have shown:

  • You reach your physical peak some time between the ages of 20 and 35.
  • During early middle age, physical activity declines and there’s a 5-10kg increase in body fat. This decline in physical activity continues into old age.
  • Your maximum heart rate declines, and your maximum oxygen uptake also declines by about 1% per year. Oxygen uptake is crucial as most of your muscle energy is made by combining oxygen with the fuel in your body (carbs, and fat). The faster you transport and use oxygen, the faster you can go, and the longer you can keep going for.
  • The mass of fast twitch muscle fibres, needed to produce power for high intensity exercise, declines sharply between the ages of 31-40 (about 3% per annum), and then continues to decline at about 1% per annum after that.

It’s not sounding too hopeful so far is it? However, there’s no reason to  throw in the towel just yet. Most of the studies that have arrived at the above conclusions have been based on declines in physical ability relative to an individual’s maximum exercise capacity, so if you’ve not been working at your maximum exercise capacity, (and most of the population other than elite athletes haven’t been), then you actually have a pretty good chance of maintaining your current physical ability, or in fact improving on past performance. With the right types and amount of training (including recovery and nutrition) you can actually win back more fitness than time takes away from you!

Looking at it another way, your maximum ability will decrease with age, no question about that, but by operating  closer and closer to your maximum ability each year, you can maintain or improve on, current fitness levels. How awesome is that?

Other studies show that age-related decline is greater in non-athletes than athletes, and as you age, the benefit you gain from vigorous activity is the same relative to the benefits younger people get from the same training.

Train Smart

Another great thing about getting older is that you have wisdom on your side. You are far more likely to treat your body with reverence, rather than disregard, taking better care of the recovery side of the athletic equation, and you’re more likely to approach training and exercise a little more scientifically than your younger counterparts.

A recent Australian study offers more good news. It found that age-related performance declines tended to be pretty insignificant in the area of aerobic performance. The study looked at the relative rates of change across the 3 energy systems across a 30 year age range. Very briefly, the 3 energy systems are:

  1. The phosphocreatine system which is the main energy source for short bursts of intense exercise (up to 10 seconds) 
  2. The lactate system – for bursts of maximal exercise lasting up to 3 minutes-involves the breakdown of carbohydrate without oxygen
  3. The aerobic system for longer, less intense exercise – fat and carbs are broken down in the presence of oxygen

The research tested men and women aged 35-64 years. As expected, there were significant changes in anearobic performance with aging (that’s the more intense stuff using mainly the first and second of the three energy systems above). What was unexpected however was that peak aerobic power hardly changed at all with age. There was a slight decline of about 1.8% per year, which the researchers found to be statistically insignificant.

These results show a couple of things about aging. One, if you’re a runner, cyclist, skier, whatever your discipline, switching to longer distances where aerobic power becomes more important, could see your performance decline less significantly as you age, at least into your mid 60’s. It also shows that aneorbic type training will become more important as you age. You’ll need to be operating at or close to your maximum capacity to counteract the natural effects of aging.

What about much older athletes?

Should you keep training into very old age, or is there a point when you should just give up because you’re too old? Well it depends on your mental state I guess, and whether you still enjoy exercising, and the benefits it brings. One study of 9 life long endurance athletes with an average age of 81 looked at their aerobic capacity, and how much oxygen their bodies can use. The results of the study led the researchers to conclude “To our knowledge, the VO2 max of these lifelong endurance athletes…[is] comparable to non-endurance trained men of some 40 years younger. The superior cardiovascular and skeletal muscle health profile of the octogenarian athletes provides them with a large functional reserve above the aerobic frailty threshold and is likely to be associated with lower risk for disability and mortality.” (Journal Applied Physiology, 2013 Jan 1;114(1):3-10


It would seem that to a large extent, the decline of performance in all but highly trained athletes as we age, is more a function of a lack of enthusiasm to train – call it what you will, laziness and apathy, lack of time, lack of interest, lack of knowledge, lack of motivation. For whatever reason, many of us, as we age, fall prey to the ravages of time far more quickly than is biologically necessary. Much of the measured and documented decline in performance of moderately fit members of the population is not inevitable as we age. We simply need to lift our game and keep exercising!

What can we do about it?

  • Train smart. Make sure each session you do is focused on developing specific aspects of your fitness. Know why you’re doing a particular session. Given we need more time to recover as we age, every session has to count.
  • Be flexible. Know your body, and adjust your training plan according to how you’re feeling. The generic half marathon training programs you can download from any race website may not be designed with 40 or 50 somethings in mind.
  • Allow longer recovery periods after particularly long or hard training sessions.
  • Pay careful attention to your nutrition. If you’re training for a long distance event, make sure you get fast release carbs and proteins into your body withing 30 minutes of completing a training session.
  • If you’re not into training for an event, good nutrition is just as important for you too. Ensure your diet is good at least 80% of the time, and really enjoy the other 20%.
  • Maximal capacity of strength and power, along with flexibility, decline more rapidly as you age, meaning you have to work a little harder in those areas. Incorporate strength and power training into your weekly training regime. If you’re a runner, this will be in the form of interval training and some resistance training. If you’re only just starting out on the exercise path, try including a session when you walk some hills at least once/week, gradually increasing the number of repetitions or gradient of the hill as you become stronger.
  • As you continue competing in fun runs as you age, you’ll be less proportionately disadvantaged if you go for longer events, however that needs to be balanced with the amount of training your body can cope with. You can use the age-graded percentage tables to compare yourself to athletes of different ages, or your younger self!
  • Your body will be more able to cope with more running miles, if you have some good strength and conditioning incorporated into your training
  • There’s no need to stop training as you get older. If you’re not already exercising, start sensibly now, and you should be able to keep it up into your 80’s and 90’s!

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