摘要:

Forty years of population studies have shown that physical activity can protect against coronary heart disease (CHD) in men of middle and early old age. Vigorous aerobic effort was required for protection of British civil servants; high levels of other activity usually accompanied this. Serious methodologic problems are illustrated from studies of these British office workers, elite Harvard alumni, and U.S. men at high risk. Because of uncertainties in defining optimal exercise, the strength of protection may be underestimated. Some possible lines of advance are suggested: collaboration between physiologists and epidemiologists to expand the content of activity information beyond caloric costs; study of sweating and hard breathing as indicators of activity that is “vigorous” for the individual; focusing on coronary thrombosis, hypothetically the principal focus of protection; a shift to measurement of cardiorespiratory, endurance fitness; and randomized trial, e.g., of high risk men with low HDL-C and high fibrinogen levels. Responding to public need and the opportunities, physical activity could be today's “best buy” in public health for the West.

ISSN:0195-9131    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Physical activity performed by patients with coronary heart disease is a two-edged sword. A number of biological changes produced by regular exercise may reduce the risk of future cardiac events, while the increase in cardiac work produced by this same exercise can predispose the patient to sudden cardiac death. Data from observational studies as well as randomized clinical trials demonstrate a lower cardiac mortality rate for men participating in exercise rehabilitation programs vs nonparticipants. Overall, exercise program participants appear to experience a reduction of approximately 25% in cardiac and all-cause mortality, but no single study has provided definitive results. During medically supervised exercise, the risk of cardiac death based on reports of programs in the United States is approximately one event in every 60,000 participant-hours of exercise. At this rate, a typical rehabilitation program that has 95 patients exercising 3 h-wk−1could expect a sudden cardiac death during an exercise session once every 4 yr. No data have been published on the morbidity or mortality benefits or risks of home-based exercise or for women participants. Also, the contribution of continuous electrocardiographic monitoring to the safety of exercise training of cardiac patients is yet to be defined.

ISSN:0195-9131    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Physical activity has been recommended by physicians in managing patients with noninsulin-dependent diabetes mellitus (NIDDM); however, it is unclear whether physical activity can prevent this disease. Several prospective studies have suggested that increased physical activity may lead to the prevention of NIDDM. In the University of Pennsylvania Alumni Health Study, 5990 men were surveyed to determine the relationship between physical activity and the development of NIDDM. A total of 202 men developed NIDDM from 1962 to 1976. Leisure-time physical activity, expressed in kilocalories (kcal) was inversely related to the development of NIDDM. Incidence rates declined as energy expenditure increased. For each 2000-kcal increment in energy expenditure, the risk of NIDDM was reduced by 24% [relative risk (RR) 0.76, 95% confidence interval (CI) 0.63–0.92]. This association remained when adjusting for obesity, hypertension, and parental history of diabetes. The protective effect of physical activity was strongest in individuals at highest risk for NIDDM. Based on the review of data from several large prospective studies, it is quite likely that increased levels of physical activity are effective in preventing NIDDM, and the protective benefit is especially pronounced in those individuals who have the highest risk of disease.

ISSN:0195-9131    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Previous investigations regarding the influence of physical activity on cancer risk generally have utilized a single assessment of activity, thus failing to account for changes over time. Additionally, one assessment may be somewhat imprecise. We attempted to overcome these problems in a study of 17,607 men (aged 30–79 yr), followed from 1962 or 1966 (1962/1966) through 1988. We assessed physical activity (based on self-reported stair climbing, walking and participation in sports or recreational activities) twice: in 1962/1966 and again in 1977. A total of 280 colon, 53 rectal, 454 prostatic, 262 lung, and 88 pancreatic cancers developed during follow-up. Among alumni with Quetelet's index ≥ 26 units, those highly active (energy expenditure ≥ 2,500 kcal [≥ 10,460 kJ]·wk−1) had 0.19 (95% confidence interval, 0.02–1.52) to 0.56 (0.29–1.09) times the colon cancer risk of those inactive (<1,000 kcal [<4,184 kJ]·wk−1). Colon cancer risk was unrelated to level of activity among alumni with Quetelet's index < 26 units. Highly active alumni also had 0.39 (95% confidence interval, 0.18–0.85) to 0.62 (0.45–0.85) times the lung cancer risks of their inactive colleagues. Physical activity was not significantly associated with risks of rectal, prostatic, or pancreatic cancers. The biologic basis for a protective effect of increased activity on cancer risk appears plausible.

ISSN:0195-9131    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Much work on the relationship of exercise level to cardiovascular risk factors has been stimulated by the pioneering epidemiological studies of Dr. Ralph Paffenbarger. At Stanford we have conducted a series of studies since 1973, with the following major findings. Very active middle-aged men and women (compared with sedentary controls) have higher plasma lipoprotein concentrations of high-density lipoprotein (HDL) cholesterol, lower levels of very-low-density-lipoprotein (VLDL) cholesterol and triglyceride (TG), and often moderately lower levels of low-density lipoprotein (LDL) cholesterol. Lipoprotein subfractions are also different: higher levels of HDL2and lower levels of “small” LDL in the active groups. Very active people are leaner and smoke less. All of these characteristics predict lower risk of coronary heart disease (CHD). A 1-yr trial of jogging in sedentary men suggested that 8–10 miles-wk−1of running is required for significant HDL changes. Body fat loss correlated positively with distance run, with increase in HDL, and withincreasein caloric intake. A 1-yr trial in overweight men showed that fat loss by dieting alone or by exercising alone results in similar elevation of HDL cholesterol. A 1-yr trial in sedentary, overweight men and women losing weight on a hypocaloric low-fat diet showed thatadditionof regular exercise increases weight loss, improves lipoprotein pattern, and further decreases 12 yr CHD risk.

ISSN:0195-9131    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Physical activity has considerable health-enhancing potential. It will be realized, however, only if large number of people participate in adequate activity. This summary report describes the main results of four studies aimed to find out whether physically active commuting to work (PACW) meets the requirements of health and fitness enhancing activity. Three successive mail inquiries (N= 2014) indicated that PACW provided habitual exercise to one-third of employed urban population, and that more than one-fifth expressed willingness and being able to increase PACW. A randomized controlled trial on 68 inactive middle-aged men and women revealed that PACW (1 h daily for 10 wk) increased VO2maxby 4.5% (P= 0.02), maximal treadmill time by 10.3% (P= 0.0007), and HDL cholesterol by 5% (P= 0.06). A demonstration project in a large industrial plant showed that PACW can be successfully promoted by low cost measures. In conclusion, these studies suggest that PACW may offer substantial potential as health and fitness enhancing measure provided that it can be practiced safely.

ISSN:0195-9131    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Quantitative estimates indicate that sedentary living is responsible for about one-third of deaths due to coronary heart disease, colon cancer, and diabetes—three diseases for which physical inactivity is an established causal factor. Presumably, if everyone were highly active the death rate from these three disease would be only two-thirds of the current rate. Note everyone will become highly active, however. Assuming smaller increases in physical activity practices, mortality from these three conditions combined could be reduced by as much as 5–6%, or 30,000–35,000 deaths per year. Overall mortality in the United States might be reduced about 1–1.5%. The greatest gains would accrue from strategies that encourage those who report no leisure-time physical activity to do some and that encourage those who are irregularly active to participate in 30 or more minutes of light to moderate activity for 5 or more d·wk−1. Mortality is only one aspect of public health burdens that would be reduced by greater participation in regular physical activity. Quality of life which we have not attempted to quantify, would also improve.

ISSN:0195-9131    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

We studied the adoption or maintenance of physical activity and other optional lifeway patterns for their influence on mortality rates of Harvard College alumni. Men aged 45–84 in 1977, surveyed by questionnaire in 1962 or 1966 and again in 1977, were followed from 1977 through 1988 or to age 90. Of 14,786 alumni, 2,343 died in 165,402 man-years of follow-up. Relative risks of death, standardized for potential confounding influences, for men who between questionnaires increased their physical activity through walking stair climbing, and sports or recreational activities to 1,500 kcal or more per wk were 0.72 (95% confidence interval 0.64–0.82), compared with 1.00 for men who remained less active. Corresponding relative risks for men who adopted moderately vigorous sports play (≥4.5 METs) were 0.73 (0.65–0.81) vs 1.00 for men not adopting such sports; and for cigarette smokers who quit, 0.74 (0.65–0.84) vs 1.00 for persistent smokers. Men with recently diagnosed hypertension had a lower death risk than long-term hypertensives (0.80; 0.70–0.92), as did men with consistent normotension (0.52; 0.47–0.58). Changes in body-mass index had little influence on mortality during follow-up. These findings fit the hypothesis that adopting a physically active lifeway, quitting cigarette smoking, and remaining normotensive independently delay all-cause mortality and extend longevity.

ISSN:0195-9131    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Exercise and noise exposure causes temporary hearing loss. Yet, a direct relationship may exist between cardiovascular health and hearing. The purpose of this study was to determine whether noise and exercise caused different levels of hearing loss depending on one's cardiovascular fitness. Twenty-eight volunteers were considered: high fit VO2peak= 48.5 ± 1.6 ml·kg−1·min−1,N= 10), moderately fit VO2peak= 38.1 ± 0.9 ml·kg−1·min−1,N= 9), and low fit VO2peak= 30.4 ± 0.9 ml·kg−1·min−1,N= 9). Hearing ability at 2000, 3000, and 4000 Hz was assessed following 10 min of noise (N), exercise (E), and noise-and-exercise (N&E). The high fit group consistently demonstrated better hearing after all conditions compared to the low fit group. Significant differences between the high and low fit groups always occurred during N&E and sometimes during N E did not cause significant hearing loss in any group. Cardiovascular health as indicated by a mean VO2peak= 48.5 ml·kg−1min−1is associated with less hearing loss after 10 min of either N or N&E. Although the mechanisms have not been identified, these results support the existence of a cardiovascular health-hearing synergism.

ISSN:0195-9131    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Three cervical orthoses often used in football to prophylactically limit motion and prevent the nerve injury known as “burners” were evaluated to determine their performance in limiting both hyperextension and lateral bending of the cervical spine. These orthoses have been used almost entirely on an empiric basis with little objective data to evaluate performance. A rope and pulley mechanism was used to pull the neck into hyperextension and lateral motion, with the only restraint being the various products tested. These trials were videotaped and the restriction provided by the collars was calculated from goniometric analysis of the projected images. These tests were performed to determine which products limit the mechanisms of the “burner” injury and thereby assess which braces might reduce or prevent the occurrence of these injuries. The results of the investigation indicate that all braces studied provided some degree of limitation in one of the mechanisms of injury, hyperextension. One brace performed superiorly in this respect. However, the other mechanism of injury, lateral bending, is inconsistently limited.

ISSN:0195-9131    

出版商:OVID    

年代:1994

数据来源: OVID