Regular Exercise Shows Benefits -- Even After Sedentary Lifestyle
The benefits of exercise have been well-documented over the years. Numerous studies have shown that exercise can help reduce incidences of disease, promote weight loss, and improve mental health.A recent study set out to examine if exercise during the senior years has benefits in people who were previously sedentary.
Canadian researchers investigated two groups of previously sedentary healthy adults, ages 55-75 years at baseline. One group remained sedentary during the study, while the other group initiated and engaged in regular exercise consisting of 30- to 45-minute aerobic sessions, three times a week, for a minimum of 46 weeks a year over the 10-year study period. Investigators evaluated the participants for fitness levels, metabolic risk factors for cardiovascular disease, and comorbid conditions.
At the conclusion of the study, researchers examined data for 161 participants in the active group and 136 participants in the sedentary group. According to the study, "The active group showed a significantly lower prevalence (11%) of the metabolic syndrome than the sedentary group (28%) at 10 years." The sedentary group also had a 13% decrease in fitness over the 10-year study period, while the exercise group showed a small increase in fitness levels. HDL, or "good" cholesterol, showed a 9% increase in the exercise group, compared to the sedentary group that showed an 18% decrease in HDL. The active group also had "fewer comorbid conditions, and fewer signs and symptoms of cardiovascular disease," than their sedentary counterparts.
Petrella RJ, Lattanzio CN, Demeray A, et al. Can adoption of regular exercise later in life prevent metabolic risk for cardiovascular disease? Diabetes Care 2005;28:694-701.
Evidence That Exercise May Help Reduce Depression
A 1997 study found that mild to moderate major depressive disorder ranked second behind ischemic heart disease in terms of years of life lost due to premature death or disability. National estimates indicate that less than one-fourth of individuals with MDD seek treatment, and only one in 10 receive adequate treatment, perhaps because of the social stigma attached with such treatment.
While exercise may be an effective treatment for MDD, primarily because it can be recommended to most individuals and does not carry a negative social stigma, insufficient evidence establishes its efficacy.
While exercise may be an effective treatment for MDD, primarily because it can be recommended to most individuals and does not carry a negative social stigma, insufficient evidence establishes its efficacy.
This study was designed to test whether exercise is a beneficial treatment for mild to moderate MDD, and to determine the dose-response relation of exercise and reduction in depressive symptoms.
Eighty adults diagnosed with mild to moderate MDD were randomized to one of four aerobic exercise treatment groups that varied total energy expenditure (7.0 kcal/kg/week or 17.5 kcal/kg/week) and frequency (three days/week or five days/week), or to a placebo control group that participated in flexibility exercises three days a week). The primary outcome measure was the score on the 17-item Hamilton Rating Scale for Depression (HRSD).
After 12 weeks, the group expending 17.5 kcal/kg/week (consistent with public health recommendations) had the lowest scores on the HRSD, while the placebo control group had the highest scores. Average HRSD scores at 12 weeks were 47% lower than at baseline. The authors conclude: "Aerobic exercise in the amount recommended by consensus public health recommendations was effective in treating mild to moderate MDD. The amount of exercise that is less than half of these recommendations was not effective."
Dunn AL, Trivedi MH, Kampert JB, et al. Exercise treatment for depression. Efficacy and dose response. American Journal of Preventive Medicine 2005;28(1):1-8.
Eighty adults diagnosed with mild to moderate MDD were randomized to one of four aerobic exercise treatment groups that varied total energy expenditure (7.0 kcal/kg/week or 17.5 kcal/kg/week) and frequency (three days/week or five days/week), or to a placebo control group that participated in flexibility exercises three days a week). The primary outcome measure was the score on the 17-item Hamilton Rating Scale for Depression (HRSD).
After 12 weeks, the group expending 17.5 kcal/kg/week (consistent with public health recommendations) had the lowest scores on the HRSD, while the placebo control group had the highest scores. Average HRSD scores at 12 weeks were 47% lower than at baseline. The authors conclude: "Aerobic exercise in the amount recommended by consensus public health recommendations was effective in treating mild to moderate MDD. The amount of exercise that is less than half of these recommendations was not effective."
Dunn AL, Trivedi MH, Kampert JB, et al. Exercise treatment for depression. Efficacy and dose response. American Journal of Preventive Medicine 2005;28(1):1-8.
Women: Exercise Quantity, Not Intensity, May Be Key
Federal guidelines encourage a minimum of 30 minutes of moderate-intensity exercise most days of the week; earlier guidelines suggested vigorous exercise for at least 20 minutes three or more times per week.
The debate between the relative benefits of moderate vs. vigorous exercise is ongoing. Additionally, the effect of time spent sitting or sedentary is unclear.
The incidence of coronary and total cardiovascular events was compared in 73,743 women ages 50-79 based on total time spent: doing any physical activity; walking; vigorously exercising; and sitting. Activity was determined by questionnaires, and classified as mild, moderate or vigorous. Over 5.9 years of follow-up in the Women�s Health Initiative Observational Study, 345 of these women were diagnosed with coronary heart disease and 309 with strokes.
The more physical activity completed (or energy expended) by subjects, the less likely they were to suffer coronary/cardiovascular events, regardless of race, weight or age. Subjects who walked or performed vigorous exercise 2.5 hours or more per week reduced their total risk for cardiovascular events by approximately 30%, while those who spent more time sitting each day had an increased risk. Although walking and vigorous exercise produced similar reductions in risk for cardiovascular events, a brisker pace when walking and less time spent sitting daily additionally reduced risk.
"Although vigorous exercise should not be discouraged for those who choose a higher intensity of activity, our results indicate that moderate-intensity exercise confers substantial health benefits for postmenopausal women," the authors conclude.
The incidence of coronary and total cardiovascular events was compared in 73,743 women ages 50-79 based on total time spent: doing any physical activity; walking; vigorously exercising; and sitting. Activity was determined by questionnaires, and classified as mild, moderate or vigorous. Over 5.9 years of follow-up in the Women�s Health Initiative Observational Study, 345 of these women were diagnosed with coronary heart disease and 309 with strokes.
The more physical activity completed (or energy expended) by subjects, the less likely they were to suffer coronary/cardiovascular events, regardless of race, weight or age. Subjects who walked or performed vigorous exercise 2.5 hours or more per week reduced their total risk for cardiovascular events by approximately 30%, while those who spent more time sitting each day had an increased risk. Although walking and vigorous exercise produced similar reductions in risk for cardiovascular events, a brisker pace when walking and less time spent sitting daily additionally reduced risk.
"Although vigorous exercise should not be discouraged for those who choose a higher intensity of activity, our results indicate that moderate-intensity exercise confers substantial health benefits for postmenopausal women," the authors conclude.
Men: Exercise Quality Important
Men who exercise at high intensity cut their risk for coronary heart disease (CHD) nearly in half, compared to sedentary individuals. Yet risk reduction has been shown for higher and lower exercise intensities, and for varying levels of energy expenditure.
Therefore, the optimal type of exercise for men wanting to reduce CHD risk is unclear.
A sample of 44,452 men, ages 40-75 and participating in the Health Professionals' Follow-up Study, completed multiple questionnaires from 1986-1998 assessing diet, lifestyle, medical history and exercise performed. Walking/hiking; jogging; bicycling; tennis; swimming; rowing; calisthenics; outdoor work; weight training; and racquetball were considered as types of exercise.
Although higher physical activity levels translated into dose-dependent reductions in CHD (men with the greatest amount of activity reduced their risk 30%, compared to sedentary men), higher exercise intensity also lowered risk 17% more than low intensity exercises. Activities that offered significant reductions in CHD risk were listed as:
* weight training (23% reduction);
* rowing (18% reduction); and
* running (42% reduction).
A faster walking pace was found to reduce CHD risk more than a slower pace, regardless of time spent walking. Traits most common in active men included: weighing less; eating less fat and more fiber; drinking more alcohol; taking vitamin E; and not smoking. The authors encourage increasing aerobic exercise intensity and total volume of activity, and adding weight training when appropriate, to reduce CHD risk in male patients.
Tanasescu M, Leitzmann MF, et al. Exercise type and intensity in relation to coronary heart disease in men. Journal of the American Medical Association 2002:288(16), pp. 1994-2000.http://jama.ama-assn.org
A sample of 44,452 men, ages 40-75 and participating in the Health Professionals' Follow-up Study, completed multiple questionnaires from 1986-1998 assessing diet, lifestyle, medical history and exercise performed. Walking/hiking; jogging; bicycling; tennis; swimming; rowing; calisthenics; outdoor work; weight training; and racquetball were considered as types of exercise.
Although higher physical activity levels translated into dose-dependent reductions in CHD (men with the greatest amount of activity reduced their risk 30%, compared to sedentary men), higher exercise intensity also lowered risk 17% more than low intensity exercises. Activities that offered significant reductions in CHD risk were listed as:
* weight training (23% reduction);
* rowing (18% reduction); and
* running (42% reduction).
A faster walking pace was found to reduce CHD risk more than a slower pace, regardless of time spent walking. Traits most common in active men included: weighing less; eating less fat and more fiber; drinking more alcohol; taking vitamin E; and not smoking. The authors encourage increasing aerobic exercise intensity and total volume of activity, and adding weight training when appropriate, to reduce CHD risk in male patients.
Tanasescu M, Leitzmann MF, et al. Exercise type and intensity in relation to coronary heart disease in men. Journal of the American Medical Association 2002:288(16), pp. 1994-2000.http://jama.ama-assn.org
Continuous, Intermittent Exercise Equally Effective
Public health efforts to encourage exercise have often included the recommendation to devote 30 continuous minutes per day to aerobic exercise, which is not an option for those with physical or time constraints.
As a result, the American College of Sports Medicine and the Centers for Disease Control changed existing guidelines to suggest a more practical approach: that 30 minutes of total moderate physical activity - continuous or intermittent - should be performed most days of the week. The effectiveness of these new guidelines has not accurately been tested, in terms of cardiovascular fitness and weight loss.
This study compared multiple variations of a 30-minute, monitored exercise program on aerobic fitness (as measured by oxygen uptake) and weight loss in college-age women. Forty-eight overweight women were divided into four groups: no exercise (the control group); 30 minutes continuous exercise per day; two 15-minutes sessions of exercise per day; and three 10-minute sessions per day. Measures of fitness, weight loss, skinfold thickness, and body circumference (hip, waist, thigh, upper arm) were taken at baseline and after 12 weeks of exercise training on a stationary bicycle.
Results: All three exercise groups demonstrated significantly increased fitness and significantly decreased weight and body measurements after 12 weeks. The results were similar between all three exercise groups. The control group did not demonstrate any significant changes. The authors concluded that exercise participation did not vary between exercise groups, with regards to average number of exercise days per week.
Exercise may have similar effects on weight loss and aerobic fitness whether performed in one long bout or several cumulative short sessions. This study implies that offering the alternative of multiple short workouts to some patients may not effectively increase their participation, however.
Schmidt WD, Biwer CJ, Kalscheuer LK. Effects of long versus short bout exercise on fitness and weight loss in overweight females. Journal of the American College of Nutrition 2001:20(5), pp. 494-501.
This study compared multiple variations of a 30-minute, monitored exercise program on aerobic fitness (as measured by oxygen uptake) and weight loss in college-age women. Forty-eight overweight women were divided into four groups: no exercise (the control group); 30 minutes continuous exercise per day; two 15-minutes sessions of exercise per day; and three 10-minute sessions per day. Measures of fitness, weight loss, skinfold thickness, and body circumference (hip, waist, thigh, upper arm) were taken at baseline and after 12 weeks of exercise training on a stationary bicycle.
Results: All three exercise groups demonstrated significantly increased fitness and significantly decreased weight and body measurements after 12 weeks. The results were similar between all three exercise groups. The control group did not demonstrate any significant changes. The authors concluded that exercise participation did not vary between exercise groups, with regards to average number of exercise days per week.
Exercise may have similar effects on weight loss and aerobic fitness whether performed in one long bout or several cumulative short sessions. This study implies that offering the alternative of multiple short workouts to some patients may not effectively increase their participation, however.
Schmidt WD, Biwer CJ, Kalscheuer LK. Effects of long versus short bout exercise on fitness and weight loss in overweight females. Journal of the American College of Nutrition 2001:20(5), pp. 494-501.
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