Spending 60 minutes every day devoted to exercise strains more than just the muscles. Most people already feel that 24 hours is never enough to get everything done. Finding that kind of time is the leading excuse for not exercising. In response to time pressures, shorter routines have been touted to give you all the benefits with less time commitment and even less sweat. But do they work?
Let's start with the joint recommendation of the U.S. Departments of Agriculture and Health and Human Services. A headline message of their new "Dietary Guidelines for Americans 2005" states that you should "engage in at least 30 minutes of moderate intensity physical activity, above your usual activity at home and at work, on most days of the week."
This means devoting a minimum of 210 minutes of exercise spread out over each week to help avoid putting on additional pounds. This amount of exercise also is likely to give you some health benefits. If you want to get fit or lose weight or if you have already lost weight and want to keep it off, 30 minutes per day won't be enough. You need to double this to an hour of moderate intensity exercise most days of the week. This means about 6 hours per week.
It's easy to see why any exercise shortcut sells if it promises results similar to those of lengthier workouts.
Popular Shortcut Workouts
Books and videos explaining and demonstrating quick workouts have been around for years. The latest programs to enter the field are the tailored studio workouts with trade names like Curves and The Blitz.
Curves is for women only and promotes itself as a place where women can get fit in a friendly atmosphere by exercising only 90 minutes per week. The basic workout is 30 minutes per session, with 3 sessions per week. The exercise routines include aerobics, strength training and flexibility. To keep exercise intensity and heart rate up, women are encouraged to move quickly from one exercise to the next.
The Blitz is a derivation of Curves modified to have greater appeal to men. To attract men with varied interests, founder Scott Smith designed the workout to include components of boxing and martial arts with resistance and aerobics. Participants move rapidly from station to station using hydraulic equipment that increases resistance automatically as you speed up your body movements. Each Blitz session lasts 20 minutes and should be done 3 times per week.
The shortest workouts have been promoted by Jorge Cruise in a series of books describing 8-minute workouts, such as 8 Minutes in the Morning for Extra-Easy Weight Loss. But Cruise readily admits that this is meant to be an extra 8 minutes of exercise per day to help you lose weight. It is not intended to be the only daily exercise. Other "8 Minute" books focus on short sessions of resistance training to build strength and muscle endurance.
One of the simplest short workouts is outlined in the book Quick Fit: The Complete 15-Minute No Sweat Workout by Richard Bradley. He has taken a standard aerobic and resistance workout and just shortened it to 15 minutes. The first 10 minutes are a brisk walk outside or on a treadmill followed by 4 minutes of strength training and then 1 minute of cool down and stretch. He recommends this routine be performed daily.
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Slow and Heavy Strength Training
Another time-saving approach to fitness suggests that once per week may be enough. In the book Power of 10: The Once-a-Week Slow Motion Fitness Revolution by Adam Zickerman and Bill Schley, the authors suggest that lifting heavier weights in very slow motion, followed by 6 days of rest, puts less stress on the body while building lean muscle mass. With more lean muscle mass, you will burn more calories. Each repetition lasts 20 seconds, a 10-second lift followed by a steady 10-second movement in the opposite direction.
There is no evidence to support this approach compared with the more standard recommendation of at least 30 minutes of devoted exercise most days of the week.
Resistance training should be done with slow, mindful movements. Most people who lift weights or use resistance machines do perform the maneuvers much too quickly. However, I have tried this very slow and heavy technique, and 20 seconds seems an eternity. The usual recommendation for weight training is to lift quickly and then slow down as you bring the weight back to the starting position, aiming for a count of 5 seconds.
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Do Exercise Shortcuts Work?
Clearly any amount of exercise is better than none. In terms of health benefits and longevity, the intensity and duration of exercise do matter. Minimal physical activity does not improve longevity, although it does improve muscle tone and probably has some health benefits.
People who engage in moderately intense exercise that burns an extra 2,000 calories per week live an average of 2 years longer than comparable people who are sedentary. Even at high intensity, you can't burn much more than 15 calories per minute. Ninety minutes per week would only get you to 1,500 calories burned, but this still will be enough to keep off some pounds, decrease blood pressure, lower risk of diabetes and likely add high-quality time to your life.
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Start with a program that is easiest for you and one that you are confident that you will maintain. If you are very sedentary, begin with minimal exertion. Work your way up to moderate intensity exercise, which means that you will notice a definite increase in your breathing and heart rate and you should break at least a light sweat.
If you choose one of the shortcuts, try to add a little extra, even if it just means 10 minutes of fast walking several times per week.
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Howard LeWine, M.D., is chief editor of Internet publishing, Harvard Health Publications. He is a clinical instructor of medicine at Harvard Medical School and Brigham and Women's Hospital. Dr. LeWine has been a primary care internist and teacher of internal medicine since 1978.