? Looking for a way to get fit quickly? High intensity interval training (HIIT) is effective, though it's hard work. Once you are fit, you can then reduce the exercise intensity to a more enjoyable (sustainable) level. Dr. Martin Gibala of McMaster University in Ontario does not believe HIIT is a heart attack waiting to happen, but recommends untrained people first get a proper medical check-up.
? HIIT can be an effective part of a weight reduction program. Overweight men who did 20 minutes of HIIT (8 second sprints with 12 seconds recovery) three times per week for 12 weeks achieved a 7 percent drop in body fat. In another study with untrained, slightly overweight women ages 30 to 45, those who did high intensity exercise lost more weight and body fat than those who did lower intensity training. One benefit of high intensity exercise is it can suppress the appetite (temporarily) compared to lower intensity exercise.
? HIIT can create a significant afterburn. Men who expended roughly 500 calories during 47 minutes of vigorous exercise continued to burn 225 extra calories in the next 18.5 hours.
? When athletes lose weight, they lose muscle as well as fat. For example, soldiers during nine weeks of combat training lost 9 lbs (4.2 kg) body weight, of which one-third was muscle loss and two-thirds fat loss. They consumed about 15 percent fewer calories than required to maintain weight.
? Even bodybuilders and figure competitors do not lose just body fat when they "lean out." In the 12 weeks pre-competition, male bodybuilders lost about 4 lbs (1.8 kg) lean body mass and 11.5 lbs (5.2 kg) body fat. The female figure competitors lost about 5.5 lbs (2.6 kg) lean and about 6.4 lbs (2.9 kg) fat.
? Why do women struggle harder than men to lose undesired body fat? Perhaps because they are women. In the animal kingdom, female animals generate less body heat after overfeeding compared to the males. Research with humans suggests similar energy conservation. When four men and four women were overfed ice cream for three days (150 percent of energy balance needs), the men burned off some of the extra calories while the women conserved energy.
? Should you believe the calorie estimates displayed on exercise machines? Not necessarily. The Precor EFX556i overestimated energy expenditure, particularly with women.
? A novel way to burn a few extra calories is to sit on a stability ball while you are at work. At a call center (where 90 percent of the time is spent sitting), employees who sat on the stability ball for five hours during the workday burned about 260 more calories per eight-hour shift. Theoretically, that could lead to loss of 26 pounds in a year! They burned about half a calorie more per minute sitting on a stability ball than sitting in a chair. The biggest barrier to using the stability balls was aggravation of pre-existing back pain.