Effect Of Leisure-time Physical Activity Research Articles

Relation of leisure-time physical activity to structural and functional arterial properties of the common carotid artery in male subjects

The structure and function of central arteries are altered with advancing age. These changes comprise arterial dilation, intima-media thickening and increase in stiffness. Arterial wall hypertrophy and increased stiffness are associated with major cardiovascular disease. In contrast to this, physical activity has been found to be inversely related to the incidence of major cardiovascular disease and mortality in humans. However, conflicting data exist on the effect of physical activity on arterial stiffness and very little data about its association with structural arterial properties. We therefore investigated the association of the self-selected leisure-time physical activity (LTPA), assessed by a self-administered questionnaire, with the structure and function of the common carotid artery, examined with high-resolution ultrasound, in 51 male subjects aged between 16 and 78 years. We found that men with a higher level of LTPA (>38.1 MET*h/week=H-LTPA) (metabolic equivalent value; 1 MET=energy expended by a person at rest, i.e. ≈3.5 ml oxygen uptake/kg body mass or 1 kcal/kg per h) had a significantly lower arterial stiffness ( P=0.02) than men with lower levels (<38.1 MET*h/week=L-LTPA) (4.32±1.17 versus 5.75±1.21×10 6 cm −2). In multiple regression analyses, with several atherosclerotic risk factors as correlating variables with arterial stiffness, LTPA persisted as an independent predictor of arterial stiffness (adjusted R 2=0.19) in addition to apolipoprotein B level (adjusted R 2=0.33). The study could not, however, show an association of LTPA with reduced intima-media thickness (L-LTPA=0.66±0.15 versus H-LTPA 0.66±0.14) or arterial dilation of diastolic diameter (L-LTPA=6.34±0.64 versus H-LTPA 6.08±0.69). However, the positive association of LTPA with several parameters, which correlated inversely with intima-media thickness, may be taken as an indicator for a possible positive (not visible in an ultrasonic examination of the common carotid artery) effect of LTPA on the arterial wall structure.

Leisure-time physical activity in relation to breast cancer among young women (Washington, United States).

It has been hypothesized that women who participate in vigorous physical activity may have lower risk of breast cancer due to lower lifetime exposure to ovarian hormones. A population-based case-control study was conducted to investigate the association between leisure-time physical activity and risk of breast cancer among women aged 21 to 45 years. Cases were 747 women diagnosed with invasive breast cancer between 1983 and 1990 in three counties of western Washington state (United States), and were identified through the Seattle-Puget Sound Surveillance, Epidemiology, and End Results (SEER) registry. Controls were 961 women selected from the same area by random-digit telephone dialing. Physical activity was assessed through personal interview, with questions on frequency and duration of each type of recreational activity during the two-year period immediately prior to reference data (date of diagnosis for cases and a comparable assigned date for controls) and between ages 12 and 21. For the two-year time period before diagnosis, there was no association with frequency of activity (age-adjusted odds ratio [OR] = 0.93, 95 percent confidence interval [CI] = 0.71-1.22 for four or more episodes per week cf none), total hours spent in physical activity (age-adjusted OR = 0.92, CI = 0.71-1.22 for four or more hours per week cf none) or MET (metabolic equivalent energy expenditure unit) (age-adjusted OR = 0.95, CI = 0.73-1.23 for 18 or more METs per week of none), nor any trend is risk with increasing activity levels. Similarly, there was no association between leisure activity during adolescence and breast cancer risk. These results were not confounded further by body mass index (wt/ht2), age at menarche, age at first full-term pregnancy, parity, family history of breast cancer, or other measured health behaviors. Our findings do not support a protective effect of leisure-time physical activity either in the adolescent years or in adulthood on breast cancer in young women.

Effect of leisure-time physical activity change on high-density lipoprotein cholesterol in adolescents and young adults.

In adults, the high-density lipoprotein cholesterol (HDL-C) level is higher among physically active subjects. However, the association of physical activity and HDL-C is less well studied in adolescents and young adults. Furthermore, it is not known whether the effect of physical activity on HDL-C levels is independent, or whether it is mediated by other physiological changes seen in exercise, such as weight loss or increased insulin sensitivity. In order to study the effects of leisure-time physical activity on the levels of serum HDL-C concentration, we analysed longitudinal data from a follow-up study of adolescents and young adults. The study subjects were participants of a large multicentre study of cardiovascular risk factors, aged 15-21 years at the beginning of the study (n = 714). HDL-C was measured from the serum supernatant after precipitation with dextran sulphate and MgCl2. A physical activity index was calculated on the basis of frequency, intensity, and duration of leisure-time activity assessed by a questionnaire. In males, an increase in the physical activity level predicted an increase in HDL-C concentration, and this association persisted after simultaneously controlling for changes in body mass index (kg/m2), subscapular skinfold thickness, serum insulin and triglyceride concentrations, and smoking. For example, an increase in the physical activity level corresponding to approximately 1 hour of intensive exercise weekly lead to an increase of 42 mumol/L in HDL-C as calculated from the regression equation. In conclusion, physical activity seems to have a direct effect on HDL-C levels among young male subjects within the usual range of physical activity levels.