First its 3x a week, then we hear an hour a day, and now the latest is only 20 minutes a week! It gets confusing!
Any media attention on fitness is a good thing I guess, as it gets inactive people more aware of the need for exercise. But just hearing bits and pieces from
extensive studies on the news can be misunderstood in the translation.
This is my answer on the question of how much should we be exercising: It depends.
More specifically, it depends on your fitness goals, whether its for weight loss,
health maintenance or athletic training. And it depends on what your diet is like.
It will take more exercise to burn excess calories just to maintain weight.
For women who want to be healthy but don't need to worry about their weight, moderate aerobic exercise for at least 20 minutes, 3 times a week plus resistance training at least twice a week is adequate. Adding yoga or pilates will improve
flexibility and strengthen the core.
For women who also want to reduce body fat, more intense aerobic exercise is needed, at least 4 times a week (more if calories are not restricted). Interval training where you push yourself to the high end of your aerobic training zone for a minute or two, then rest for a minute is very effective and efficient. Strength training with heavy weights is the best way to rebuild lost muscle mass as we age, to boost metabolism and burn more calories.
One mistake I think alot of women make is that the only exercise they do on a regular basis is walking around the neighborhood. A fast-paced walk to elevate the heartrate is fine for cardiovascular health but it is at a very low to moderate aerobic intensity. For weight control, higher intensity exercise with more muscles
engaged plus strength training should also be included.
The key to exercise is that some is better than none but the proper amount can make a world of difference to your health and how you look and feel!