Comment by thegn on A quick calculation on exercise · 2014-10-23T23:27:08.902Z · LW · GW

In general, it's more important to exercise regularly than for massive periods of time. In fact, the massive periods of time required by athletes are often detrimental to health (performance not always equaling health, for example see serious injuries in elite athletes as a result of their sport) and should be avoided by those without significant performance goals.

A single workout per week involving both cardio and weight training is sufficient for many people provided diet is in check. 45 minutes or less is the ideal number - many people will do 15-20 minutes of cardio with the remainder being made up of high-intensity interval/circuit weight training covering most major movements. However, ideally, short workouts daily are more useful than longer workouts less frequently.