You have to work out for 45 minutes at a time to get anything out of exercise.

Monday, September 28, 2009

I am not an expert in exercise physiology, but the research
is clear that most people don’t get enough these days. There
are good studies that show that even walking 30 minutes three
times a week has tremendous benefit.

Ideally your target should be at least 30 minutes 5 times a week.
The good news is that breaking this up into two 15 minute segments
works fine. That’s not much—a couple of miles walking instead of
a single sit-com on television. Walking is a lot more fun than
watching the evening news and so much better for you. When you do
exercise, try to work a little harder at it each time you do. Begin
with a stroll for 30 minutes but within a month you can be up to a
brisk walk.