If exercise is good for losing weight, more must be better, right? Not according to new research carried out at the University of Copenhagen in Denmark. At least in this study, exercising longer didn’t lead to more weight loss. One more reason to increase the intensity of your workouts rather than their duration.
Researchers divided 60 overweight men into two groups. Both groups exercised at a moderate pace by either running or cycling. The only difference was the amount of time they exercised. One group exercised at a moderate intensity for 30 minutes a day while the other group worked out for a full hour. During the study, researchers followed their body weights closely. At the end of the 13 weeks study, the group who worked out for 60 minutes a day lost an average of 6 pounds. Surprisingly, the group that only sweated 30 minutes a day lost more weight. On average, they lost 8 pounds.
Why More Exercise Won’t Necessarily Lead to Greater Weight Loss
Intuitively it would seem that the group that exercised for 60 minutes, twice as long as the other group, would have experienced more weight loss. After all, they expended more calories. Why didn’t it work this way?
Several issues could be at play here. For one, more prolonged exercise sessions may have stimulated their appetite and motivated them to eat more. It’s not hard to compensate for the additional calories you burn through exercise with diet. For example, if the men ran at a 10 minute per mile pace, the group that exercised for an hour would have burned around 540 calories, while the group that ran 30 minutes would have expended 270 calories. This 270 calorie differential wouldn’t be difficult to compensate for by eating a little more during the day. That’s why some research suggests that exercise alone doesn’t lead to significant amounts of weight loss in people who are overweight. Diet and nutrition are equally, if not more, important than how long you exercise, especially when you’re working out at a moderate pace where you don’t experience a significant afterburn effect. Also, keep in mind that studies on humans are difficult to control as participants usually don’t exactly follow the nutrition and exercise program they’re supposed to do in the study.
Another Reason Why Longer Periods of Exercise Don’t Lead to More Weight Loss
Another way some people compensate for longer exercise sessions is by expending fewer calories later in the day. After a long workout, you feel more fatigued. This could make you less motivated to get up and move around the rest of the day so you’d burn fewer calories than you normally would during your daily activities. It’s your body’s compensation mechanisms at work again.
What Does This Mean?
More exercise isn’t necessarily better when you’re trying to lose weight. It’s easy to make up for the additional calories you burned by working out an extra 30 minutes by eating a little more. You may even feel “entitled” to eat more since you exercised so hard. Plus, you may unconsciously slow down the pace of your activities for the rest of the day.
Instead of doing a longer routine, use the time you currently exercise more efficiently – by increasing the intensity. High-intensity intervals will force your body to burn more calories even after you’ve finished as you expend more energy during the recovery phase. When you factor in the hormonal effect of shorter, more intense exercise, including greater increases in growth hormone and testosterone, you’ll ultimately burn more body fat when you work out harder for shorter periods of time. But since you shouldn’t do high-intensity interval training more than two or three times per week you can still mix in your longer steady state cardio workouts into your weekly workout schedule. This will help you to avoid overuse injuries and will keep your body constantly challenged in different ways.
Strength Training Should Be a Priority Too
This study only looked at aerobic exercise, and strength-training is no less important since it builds metabolically-active lean body mass that helps you burn more fat over the long run. You may need to work out more than 30 minutes a day so you can fit in an appropriate amount of strength-training but use that time to focus on strength exercises rather than spending another 30 minutes running or cycling. Ultimately, you’ll get more benefits when you balance cardio with resistance training. Lastly, don’t forget the importance of nutrition. If you’re trying to lose weight, keep a food journal to see when you’re compensating for exercise by eating more.
The Bottom Line?
More isn’t always better when it comes to aerobic exercise. Increase the intensity of your cardio sessions and keep them shorter. Then balance it out with strength-training for a strong, lean physique.
References:
EMedicineHealth. “Thirty Minutes of Daily Exercise Enough to Shed Pounds”
American Journal of Physiology News Release. August 1, 2012.
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