Health notes & news from around the globe.

In a study mentioned in the New England Journal of Medicine, researchers from the Mayo Clinic measured the calorie-burning effects of chewing gum. Seven participants, all of normal weight, sat in a darkened room and, for 12 minutes, chewed the equivalent of six pieces of sugarless gum at a rate of 100 chews per minute. As a result, the participants burned an extra 11 calories an hour, a 20 percent increase over normal resting values.

While this study may seem like another attempt to give people unrealistic alternatives to exercise, Dr. James Levine, the lead re-searcher of the study, has made it quite clear that he is not advocating chewing gum as a method of weight loss. He stated that the study simply shows that very minor changes in non-exercise activity can have an impact on energy expenditure. He added that exercise combined with a sensible diet is the best way to lose weight.

In a recent edition of New Scientist magazine, Australian physiotherapists claimed that stretching to loosen up muscles doesn't provide any benefit for exercisers. The researchers studied two group of army recruits during the course of a year. One group stretched prior to exercise, while the other group did not. At the end of the year, the researchers found the rate of injury didn't differ between the two sets.

Researchers from the University of Minnesota in Minneapolis have found that postmenopausal women who exercise regularly are less likely to develop diabetes than their sedentary peers. As part of a 12-year study, the researchers tracked the exercise activity of 41,000 women, age 55 to 69. The women who exercised moderately or vigorously more than four times per week had half the risk of diabetes compared with women who never or rarely exercised.