Background: Physical performance often declines in middle age, but it is unclear to what extent this is due to biological aging. It can be difficult to determine whether such physical changes are truly age-related, as they might alternatively be explained as the negative consequences of a sedentary lifestyle.
Methods: We assessed the endurance of a physically active subgroup of the population by performing an age- and sex-stratified analysis of over 900,000 running times of marathon and half-marathon participants aged 20 to 79. We also analyzed the responses of 13,171 marathon and half-marathon runners to a questionnaire about sports, lifestyle, and health.
Results: No significant age-related decline in performance appears before age 55. Moreover, only a moderate decline is seen thereafter; in fact, 25% of the 65- to 69-year-old runners were faster than 50% of the 20- to 54-year-old runners. Our survey also revealed that more than 25% of the 50- to 69-year-old runners had started their marathon training only in the past 5 years.
Conclusion: Performance losses in middle age are mainly due to a sedentary lifestyle, rather than biological aging. The large contingent of older "newcomers" among marathon runners demonstrates that, even at an advanced age, non-athletes can achieve high levels of performance through regular training.