Research · 3 min read · 2026-10-12
Running as you get older
Endurance holds up until about 35 and falls modestly until 50 to 60. Much of the decline comes from training less and slower.
Many runners start or keep running well into their forties, fifties and beyond. What happens to endurance with age, and what can training keep?
What the researchers did
Researchers from the University of Texas and the University of Colorado reviewed research on older endurance athletes, often called masters athletes. They described how peak endurance performance changes with age and which parts of the body's capacity explain it.
What they found
Peak endurance performance held up until about 35 years of age. After that it fell modestly until 50 to 60, and more steeply after that.
The main reason was a gradual drop in maximal oxygen uptake. The lactate threshold also fell. Running economy, how much energy you use at a given pace, did not change with age in trained runners.
The authors concluded that much of the decline comes from the fact that older athletes train at lower speeds and do less training.
What it means for you
Some decline is inevitable, but less of it is fixed than many think. Keeping some faster running in your week matters as you get older, because intensity is the part of training that tends to disappear first.
Economy is something you keep. Many older runners run very efficiently, and strength training can help keep the muscles strong.
What the study can't tell you
Much of the data comes from comparing the best results at different ages, not from following the same runners over many years. How fast an individual runner declines varies a lot.
How we use it
PX7 Training builds your targets from your own recent races and runs, not from your age. As your form changes, your targets change with it, and your recovery decides how the harder sessions are spaced.
Source
- Tanaka & Seals (2008), Endurance exercise performance in Masters athletes: age-associated changes and underlying physiological mechanisms. The Journal of Physiology.
Written by Jørgen Larsen for PX7 Training.