On Target - Weekly Journal, Issue September 23, 2001
Exercise and Aging
According to an article published in the journal Circulation (2001;104:1350-1357), even substantial decreases in cardiovascular fitness resulting from decades of inactivity can be substantially reversed with modest endurance training. The findings are based on a study of five men who participated in the Dallas Bed Rest and Training Study. In 1966, when the men were 20 years of age, their cardiovascular fitness was evaluated at baseline and after 20 days of bed rest. Results showed that 20 days of bed rest compromised their cardiovascular fitness in most hemodynamic measures. When these same men were in their early 50s, they were reevaluated for their cardiac fitness. Only one of them had engaged in regular physical activity. According to the authors, the most interesting finding was that based on the baseline data from the 1966 study, 30 years of aging appear to be not as bad on cardiovascular fitness as 20 days of bed rest was when the subjects were 20 years old. Over 30 years the average body weight increased by 25%, percent of body fat doubled, average maximal oxygen uptake decreased (11%), as did maximal heart rate (6%). Maximal stroke volume increased (16%) with no difference in cardiac output. In addition, maximal AV oxygen difference decreased by 15%. In the second part of the study the men underwent a 6-month endurance training program consisting of walking, cycling or jogging. Results showed that after a relatively modest 6-month endurance training program, the subjects were able to get back to an aerobic power level consistent with their 20-year-old baseline. According to the authors, when the men were 20 years old their response to exercise training was both central and peripheral adaptation. When the subjects were 50 years old, almost the entire decrease in cardiovascular fitness occurred as a result of a loss of the ability to take up and use oxygen. The gain that the men achieved was all peripheral adaptation. The author noted that the reasons for this change in cardiovascular response to exercise with age are unknown.
Exercise and Aging
According to an article published in the journal Circulation (2001;104:1350-1357), even substantial decreases in cardiovascular fitness resulting from decades of inactivity can be substantially reversed with modest endurance training. The findings are based on a study of five men who participated in the Dallas Bed Rest and Training Study. In 1966, when the men were 20 years of age, their cardiovascular fitness was evaluated at baseline and after 20 days of bed rest. Results showed that 20 days of bed rest compromised their cardiovascular fitness in most hemodynamic measures. When these same men were in their early 50s, they were reevaluated for their cardiac fitness. Only one of them had engaged in regular physical activity. According to the authors, the most interesting finding was that based on the baseline data from the 1966 study, 30 years of aging appear to be not as bad on cardiovascular fitness as 20 days of bed rest was when the subjects were 20 years old. Over 30 years the average body weight increased by 25%, percent of body fat doubled, average maximal oxygen uptake decreased (11%), as did maximal heart rate (6%). Maximal stroke volume increased (16%) with no difference in cardiac output. In addition, maximal AV oxygen difference decreased by 15%. In the second part of the study the men underwent a 6-month endurance training program consisting of walking, cycling or jogging. Results showed that after a relatively modest 6-month endurance training program, the subjects were able to get back to an aerobic power level consistent with their 20-year-old baseline. According to the authors, when the men were 20 years old their response to exercise training was both central and peripheral adaptation. When the subjects were 50 years old, almost the entire decrease in cardiovascular fitness occurred as a result of a loss of the ability to take up and use oxygen. The gain that the men achieved was all peripheral adaptation. The author noted that the reasons for this change in cardiovascular response to exercise with age are unknown.
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