As a 47-year-old guy, I know that too much of a good thing is a bad thing. One common misconception I hear often is the idea that lots of endurance training is good for you. For guys over 40, this isn’t necessarily true.
Prolonged endurance training, like long bike rides, will tend to raise cortisol levels. This can lower sex hormone levels in both men and women.
When I ride, I prefer shorter duration and higher intensity rides (usually 1-2 hours at the most). This window is enough to provide a training stimulus without creating too much stress on the body.
We frequently help over-trained endurance athletes who’ve lost their sex drive and are dealing with fatigue. The problem, which may be hard to believe, is too much exercise. So the first thing we need to do is dial these guys back, get them into the gym to lift some weights, and teach them that after 40, for most guys less is more.