Aerobics suppresses appetite, controls weight, says study

London, December 14, 2008: A new study suggests that 60 minutes of strenuous aerobic exercises on a treadmill are far more effective in suppressing the urge for food, than 90 minutes of weightlifting.

When we perform aerobic exercises, two important appetite hormonesdefine are released by the body. These are called ghrelin and peptide YY. On the other hand, weightlifting affects the level of only one of these, i.e. ghrelin.

This finding can actually lead to the development of effective exercises that can help control weight, said co-author of the study, David J. Stensel of Loughborough University in Britain.

Peptide YY was discovered by scientists less than 25 years ago whereas ghrelin was discovered in Japan about ten years ago.

Although there are many hormones that regulate appetite, the researchers focused only on the two most important ones, i.e. ghrelin and peptide YY. While ghrelin stimulates appetite, peptide YY suppresses it.

In the latest study, 11 male university students were made to do three eight-hour sessions. During the first session, they were made to run on a treadmill. After this, they rested for seven hours.

Then, in another session, they did 90 minutes of weightlifting and rested for six hours and 30 minutes. And in the third session, the students did not perform any exercise.

As each session went on, the participants were made to fill forms in which they rated how hungry they felt at different points. During each session, the participants were also provided with two meals. Ghrelin and peptide YY levels were calculated by the researchers at various points as the session went on.

It was discovered that there was a fall in ghrelin levels after the treadmill (aerobic) session, while the peptide YY levels increased. This means that overall there was suppression in appetite.

On the other hand, the weightlifting, i.e. non-aerobic session showed mixed results. While the ghrelin levels went down, there was no significant change in the level of peptide YY.

Based on the survey forms filled by the participants, it was found that both aerobic and non-aerobic exercises suppressed hunger, but the former led to a major suppression in hunger.

But the changes noted by the observers were short term for both types of exercises. This lasted for about two hours and included the time spent exercising.

The findings of the study have been published in the online edition of the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology.