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Welcome to the future
An interesting study that should both reassure and inspire us was recently published in the journal Circulation (2001;104:1350–66). This study raises the issue of the role of sports and exercise medicine in the broader context of public health.
Many of us who see ourselves as “couch potatoes” or “mouse potatoes” to use the appropriate computer jargon, lament the passing of our former fitness. Well, hope is at hand. A study with a remarkable name, the Dallas Bed Rest and Training Study, has found in a 30 year follow up, that just six months of exercise can reverse the decline in cardiovascular capacity associated with aging. However, just three weeks of bed rest has a far more profound negative effect on cardiac fitness than aging alone.
The study findings showed that men who undertook a six month endurance training programme of walking, jogging, or stationary cycling were able to completely recover the aerobic fitness they had lost in the previous 30 years. None of the men had complications from the exercise and all managed to stick to their exercise regimen. Their training level increased weekly until at the end of six months they were exercising four hours per week over four to five sessions.
The study focused on five healthy men who at the age of 20 originally took part in the landmark Dallas study, and then participated in the 30 year follow up study. In the 1966 study, they did eight weeks of intensive exercise training after 20 days of bed rest. In the follow up, they were evaluated for the effects of age on cardiovascular response to exercise testing and cardiovascular adaptation to an exercise programme.
Researchers found that 20 days of bed rest at the age of 20 had a far more profoundly negative impact on cardiovascular fitness than did 30 years of aging. Over 30 years, the mens' body weight increased by 30% and their body fat doubled. Their Vo2 max decreased by 11% but unexpectedly the decrease was mainly due to an impaired efficiency in the peripheral oxygen extraction. There was no decline in maximal cardiac function despite the three decades of aging, with a decline in maximal heart rate balanced by an increased in maximal stroke volume.
The researchers concluded that physical activity accounted for as much as 40% of the age related decline in aerobic fitness. In the second phase of the study, the mens' loss of cardiovascular fitness in the previous 30 years was completely restored by the six month training programme. The Circulation study adds to the body of information on exercise and health but it also provides hope that one of the groups with the highest levels of cardiovascular problems—that is, middle-aged men—may be amenable to remarkably simple exercise prescription.
How then do we take this information into our clinical practice? This study is in line with previous studies demonstrating that in older patients relatively low intensity exercise can have a significant effect on health, injury prevention, and well being. Interestingly, another recent study (Rheumatology 2001;40:772–8) demonstrates the value of exercise in injury treatment. This study suggests that regular aerobics classes may be effective therapy for chronic low back pain. Although intuitively sensible, the far more interesting aspect of the study was that aerobics was equally as effective as either muscle reconditioning programmes and physiotherapy treatment.
Our duty then as sports physicians should be to consider the wider public health setting and to encourage exercise in all our patients. What a strangely simple idea in this new millennium!
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