The answer might be surprising. You should already know that exercise intensity is the single most important variable in maximising the health benefits of exercise. You can read more in my post How Important Is Exercise Intensity? But what of duration?
I’m aiming this squarely at non-exercisers when I say you don’t need much exercise.
The graph shows the risk of disease from varying levels of physical activity.
The moral is, if you’re sedentary (the blue bar), your risk of exercise-preventable disease is high. If you do only a small amount of exercise (red), the risk drops markedly. Major increases in duration from this point only elicit a small improvement in disease resistance.
Share this information with someone you know doesn’t exercise. The knowledge that a little can have a big effect may just be the motivation they need.