The First 20 Minutes Personal Trainer: The Right – and the Wrong – Workouts for Everyone

The amount of exercise needed to improve health and longevity seems to be surprisingly modest, and more is not necessarily better.

They walked hard for one minute and easy for the next, and after several months had gained endurance, lost weight and improved their cholesterol profiles and blood pressure.

The structure of the sessions is easy. Warm up briefly by pedalling, jogging or stroking gently for a minute or two. Then push yourself hard for one minute, ease off for one minute, and repeat that sequence 10 times.

People who exercise or compete for more than 45 to 60 minutes need to replenish their body’s fuel with carbohydrates’ – i.e. sugar, said Dr Luc van Loon, a professor at Maastricht University Medical Centre in the Netherlands, who’s long studied sports nutrition.

Human appetite is complicated, driven by signals from the brain, gut, fat cells, glands, genes and psyche. But certain appetite-related hormones, particularly ghrelin, which stimulates hunger, directly affect how much we consume. Exercise typically increases ghrelin. Workouts, in other words, make you hungry. And in this study, when the women ran, their ghrelin levels spiked, which should have meant they would attack the buffet with gusto. But they didn’t. In fact, after running they consumed several hundred fewer calories than they burned.

Their restraint, the researchers found, was due to a simultaneous increase in hormones that initiate satiety. These hormones, only recently discovered, tell the body that it has taken in enough fuel; it can stop eating. The satiety hormones, the authors write, ‘muted’ the message from ghrelin after the women ran.

Exercise will not rev up your metabolism much. So if you want to lose weight, you’ll need to consume fewer calories than you burn. Don’t linger at the all-you-can-eat buffet after a workout. And if your main goal from exercise is to get thinner, consider running or other relatively vigorous types of exercise. They seem to better hone the body’s satiety mechanisms than walking.

A few recent studies have shown that if you stick with the right kind of exercise, you may change how your body interacts with food.

In exercise, as in most things, moderation may be best.

LINE:At best, you’re probably wasting your time with stretching before exercise.