We examined age-related changes in endurance performance of marathon and half-marathon finishers. A total of 405 515 running times were separated into groups based on age, sex, and distance. After exclusion of repetitive running times, 300 757 runners were analyzed by ANOVA (factors: age, sex). For each age group (six decades, 20-79 years), mean running times for all finishers, as well as top-ten performers, were assessed. As expected, age and sex had significant influence on running times. Female running times were about 10 % (marathon) and 13 % (half-marathon) above the corresponding times of their age-matched peers. The main finding is that in our sample of trained subjects significant age-related losses in endurance performance did not occur before the age of 50 years. Mean marathon and half-marathon times were virtually identical for the age groups from 20-49 years. Moreover, age-related performance decreases (p < 0.01) of the 50 - 69-year-old subjects were only in the range of 2.6 - 4.4 % per decade. These results suggest that the majority of older athletes are able to maintain a high degree of physical plasticity. The hypothesis that lifestyle factors have considerably stronger influences on functional capacity than the factor age is also supported by these findings from physically active and fit elderly.