Aerobics help in weight loss

Sixty minutes of vigorous aerobic exercises on a treadmill is better than 90 minutes of weight-lifting in suppressing appetite.

Aerobics do so by modifying release of two key appetite hormones, ghrelin and peptide YY, while weight-lifting affects the level of only ghrelin, according to a new study.

This line of research may eventually lead to more effective ways to use exercise to help control weight, according to co-author, David J. Stensel of Loughborough University in Britain. There are several hormones that help regulate appetite, but the researchers looked at two of the major ones, ghrelin and peptide YY. Ghrelin is the only hormone known to stimulate appetite. Peptide YY suppresses appetite.

Ghrelin was discovered by researchers in Japan only about 10 years ago and was originally identified for its role as a growth hormone. Only later did its role in stimulating appetite become known. Peptide YY was discovered less than 25 years ago.

In this experiment, 11 male university students did three eight-hour sessions. During one session they ran for 60 minutes on a treadmill, and then rested for seven hours.

During another session they did 90 minutes of weight lifting, and then rested for six hours and 30 minutes. During another session, the participants did not exercise at all, said a Loughborough release.

During each of the sessions, the participants filled out surveys in which they rated how hungry they felt at various points. They also received two meals during each session. The researchers measured ghrelin and peptide YY levels at multiple points along the way.

They found that the treadmill (aerobic) session caused ghrelin levels to drop and peptide YY levels to increase, indicating the hormones were suppressing appetite. However, a weight-lifting (non-aerobic) session produced a mixed result. Ghrelin levels dropped, indicating appetite suppression, but peptide YY levels did not change significantly.

Based on the hunger ratings the participants filled out, both aerobic and resistance exercise suppressed hunger, but aerobic exercise produced a greater suppression of hunger.

The changes the researchers observed were short term for both types of exercise, lasting about two hours, including the time spent exercising, Stensel reported.

The study appears in the online edition of The American Journal of Physiology-Regulatory, Integrative and Comparative Physiology.

fer: thetimesofindia