How to lose up to two pounds of fat a year while you’re asleep!
If you want to lose weight, you’ve got two options: You can either:
(1) expend more energy or
(2) take in less energy.
A variety of scientific research then showed that exercise could stop this vicious cycle. For one thing, exercise helped maintain muscle mass, and it also seemed possible that exercise could raise – not lower – metabolic rate during the time periods between workouts.
However, studies weren’t always able to show that exercise really raised metabolic rates, nor was it clear that the potential increases in metabolic rate were substantial enough to make a difference for weight loss. Scientists were also unclear about how different types of exercise influenced metabolic rate. It was certain that a long, intense run, for example, could raise metabolic rate significantly during the post-workout hours, but what about other sports such as weight lifting?
Now, scientists at the University of Limburg in the Netherlands have some good news: weight training can increase the quantity of fat that you burn while you sleep! In the Limburg research, 21 healthy males between the ages of 25 and 45 who had not previously participated in a weight-training programme trained vigorously twice a week over a 12-week period. Each workout lasted about 90 minutes and consisted of a 10-minute warm-up on an exercise bicycle, 14 exercises with free weights and machine gym equipment, and then five minutes of cooldown cycling and stretching. The 14 exercises included flys, seated lat pulldowns, leg presses, butterflys, triceps pushdowns, sit-ups, calf raises, leg curls, chest presses, leg extensions, shoulder raises, leg raises, and preach er bench curls. Subjects usually completed two to three sets of 10-15 reps per exercise.
At the end of the 12-week period, metabolic rate hadn’t budged by an inch. The subjects were burning about one calorie per minute as they slept before the study began – and after it was over, too. That was in spite of the fact that the weight trainers lopped off about five pounds of body fat during the study and tacked on about two new pounds of sinewy muscle and bone. Muscle has a higher metabolic rate than fat, so you might have reckoned that whole-body metabolic rate would have gone up.
Although metabolic rate was unchanged, the training programme did produce one very pleasant effect, in addition to the muscle gain and fat loss. The rate at which the athletes burned fat WHILE SLEEPING increased by 7 per cent. Although athletes continued to burn just one calorie per minute during sleep, a larger ‘chunk’ of that calorie was contributed by fat. Over time, this could lead to continued, valuable improvements in body composition. In fact, assuming that the fat-burning gain during sleep amounted to about one-twentieth of a calorie per minute, the uplifted fat metabolism could produce about a two-pound loss of fat each year – and even greater fat trimming if the effect was present throughout the day.
The bottom line? Weight training is an excellent activity for runners and other sports-active people. In addition to fortifying the legs against injuries, weight training can burn six to 12 calories per minute during a workout (the higher figure applies when you’re working your leg muscles vigorously), and can increase fat metabolism when you’re at rest.
Why didn’t the weight-training programme raise metabolic rate? It’s possible that a longer period of time – and greater gains in muscle mass – might have been needed to really stoke the metabolic fires.
(‘Effect of Weight Training on Energy Expenditure and Substrate Utilization during Sleep, (Medicine and Science in Sports and Exercise, vol. 27(2), pp. 188-193,1995)