Is performance loss inevitable in distance running as we age?
If so, when does the rot set in?
Endurance athletes begin to slow in their mid to late 30s, and sadly, performance declines more as we age. Many exercise scientists claim that 20% - 40% of physiological deterioration from ageing is not inevitable as long as we keep exercising.
Dozens of studies have quantified the reduction in running performance times from ageing. A reduction of 0.5% to 1.0% per year in racing performance from age 35 to 60 in distance events from the mile to the marathon is the norm. But all is not lost. For runners who stay in the game, continuing to run and compete vigorously into later life, this decline in performance slows drastically.
Aerobic capacity decreases with ageing. From 30-70 years we can lose 40% of our VO2 max potential, primarily caused by a reduction in our maximal heart rate of one heartbeat per year, and a decline in stroke volume. Interestingly, a study by Rogers et al found that endurance training slows this drop in maximal heart rate.
And more good news for runners: Research shows that VO2 max. declines only half as fast, or less, in runners as in sedentary individuals. Runners' VO2 max. only declines by 0.5% per year, as long as some higher intensity running is included in the training program. One study found no decline in VO2 in runners who maintained their training for ten years. Additionally, highly trained ageing runners maintain their stroke volume for longer and extract more oxygen from circulating blood to compensate for the lower volume of blood being distributed.
Less encouraging for the runners who completely give up their sport, is their much larger decline in VO2 max - up to 43% between ages 23 and 50, at a decline of 15% per decade, or 1.5% per year. Perhaps more encouraging for older people contemplating taking up running or jogging for exercise is that people over 65 years can experience a 20-30% increase in VO2 max after taking up running.
Despite these clear physical advantages that running gives us over non-runners, most of us will still have to cut back our training volume (reported by 39% of older runners) and intensity (reported by 73% of older runners) due to age-related physiological factors, according to a survey by Jaffee et al. Our muscles and joints feel the ageing pinch before our aerobic capacity does - more aches and pains are reported by 53% of older runners. Many of us face significantly reduced running with the onset of osteoarthritis to the point where we can only do one to three training runs per week. Weight gain is reported by 47% of older runners. We seem to have less energy (reported by 48% of older runners). Thus our training and racing distance and pace slows down.