How much exercise?
by Barbara A. Brehm, Ed.D.
WHEN YOU READ about the health benefits of physical activity, it almost sounds like an ad for snake oil. "When used according to directions, this product can help you lose weight, age more slowly, reduce stress and tension and sleep better; it tones muscles, strengthens joints and bones, and prevents artery disease, high blood pressure and diabetes." Sounds too good to be true. Do all exercise programs really deliver all of these benefits?
To maximize the health benefits of your exercise program, you need to include the right amounts of the right kinds of activities in your program, including:
Aerobic exercise challenges energy production systems. Our bodies adapt to exercise demands by improving these systems. Benefits include improved fat metabolism and higher levels of HDL cholesterol (the "good" kind associated with reduced risk of artery disease). Greater insulin sensitivity (cells respond better to insulin) results in better blood sugar regulation, which also reduces artery disease risk. Regular aerobic exercise reduces the tendency of blood platelets to clump together, thus decreasing the likelihood of dangerous blood clots. The heart becomes a more efficient pump and beats more slowly at rest. Aerobic exercise requires energy expenditure; we burn calories that might otherwise be destined for storage as fat.
When we apply force against a resistance, such as elastic bands or a stack of weights, our muscles, bones and joints adapt by becoming stronger. Denser bones are more resistant to osteoporosis, and stronger muscles and joints are less prone to injury. Maintaining adequate strength is especially important as we age. Many older adults become so weak they can no longer perform the essential tasks required for independent living, such as grocery shopping and meal preparation. While some loss of strength does appear to be an inevitable part of the aging process, much of the decrease in strength observed in many older people is due to a sedentary lifestyle. Some researchers have noted that with regular resistance training, such age-related loss of function could be postponed at least 10 to 20 years for most people.
Adequate joint flexibility prevents injury and chronic musculoskeletal problems, such as low-back pain. Like strength, flexibility declines as we age. Regular stretching can slow this decline and reduce that stiffness that keeps us from enjoying activity.
The following are recommendations for the minimal amount of exercise required for producing the benefits described above:
Aerobic activity:
3 to 5 times per week
20 to 60 minutes per session
Resistance training:
2 times per week
8 to 12 reps per exercise
8 to 10 exercises, including all muscle groups
Stretching:
3 to 5 times per week
Aerobic exercise appears to be beneficial even at fairly low intensities. But the lower the intensity, the longer the workout duration needs to be. In other words, 20 minutes per session is enough if you are working at a high intensity. If you are walking at a moderate pace, 45 minutes to an hour would be a better length.
Of course, you will want to be sure any changes you make in your exercise program are right for you, and that you are performing new exercises safely and effectively. Check with your doctor if you have health risks or concerns.
In addition to the basic recommendations given above, daily activity of every kind contributes to physical fitness and good health. Taking the stairs instead of the elevator, walking your errands, volleyball on the beach, working in the garden, playing with the kids. All burn calories and contribute to a high-energy
lifestyle that reduces risk of heart disease.
If you are new to exercise, build your exercise program gradually. You are in it for the long haul - it's a lifetime of activity that counts. Ask your instructor for help designing a program that is right for you, one that takes into consideration your health concerns and fitness goals. Your objective for the first few months is to stay injury-free and healthy, and set up a routine that's going to become a lifelong habit.
Do these recommendations seem overwhelming? Start small! What about two exercise sessions per week that include some aerobic exercise, 10 to 15 minutes of weight work and five minutes of stretching. Maybe a walk on the weekend. This routine would contribute significant health benefits over the years.
Barbara A. Brehm, Ed.D., is Associate Professor of Exercise and Sport Studies at Smith College, Northampton, Massachusetts.
______________________________________________________________________________
| Title |
How Much Exercise? |
| Author |
Barbara A. Brehm, Ed. D. |
| Source |
Fitness Management |
| Vol (iss) |
8(11) |
| Pages |
p31 |
| SIRC ID# |
309415 |
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