A sample of 399 boys, 8 to 15 years of age, underwent a comprehensive evaluation to determine the extent to which coronary artery disease (CAD) risk factors are related to an estimate of cardiorespiratory fitness. The boys were divided into four groups on the basis of their directly measured VO2max. Significant differences were found between fitness groups for relative body fat, plasma triglycerides, systolic and diastolic blood pressure, and systolic blood pressure divided by height, with the higher fitness groups exhibiting substantially lower values. When covariance analyses were conducted, adjusting for differences in age and relative body fat, the differences in blood pressure were no longer statistically significant. No differences were found between fitness groups for total cholesterol, HDL-C, LDL-C, or the ratio of HDL/TC. It is concluded that there is not a strong relationship between cardiorespiratory fitness and CAD risk factors in boys 8- to 15-years of age.
Anneke Kwee and Jack H. Wilmore
Huan Zhao, Xiao-Qiu Chu, Xiao-Qing Lian, Ze-Mu Wang, Wei Gao and Lian-Sheng Wang
Exercise leads to a lower risk of coronary artery disease (CAD). However, whether time of day physical exercise has effects on CAD is still unclear. The present study is to investigate the relationship between time of day physical exercise and angiography determined CAD in a Chinese population.
A total of 1,129 consecutive participants who underwent coronary angiography for the first time were enrolled in our study. Participants were divided into non-CAD group and CAD group according to the result of coronary angiography. We used a predesigned questionnaire—the work-related activity, leisure-time activity, and physical exercise information were recorded in the form of self-reporting.
Doing physical exercise was associated with a reduced risk of CAD, after adjusting the established and potential confounders, with an adjusted odds ratio (OR) of 0.48 (95% CI, 0.35–0.67) compared with those who did not any physical exercise. Moreover, the risk of CAD could linearly decrease with increase of intensity, duration and frequency of exercise. Further stratification analysis revealed that the protective effects of exercise were more significant in the afternoon and evening group than in the morning and forenoon group. The adjusted ORs of doing physical exercise in morning, forenoon, afternoon, and evening groups were 0.53 (0.36–0.78), 0.51(0.27–0.96), 0.46(0.25–0.85), 0.43(0.28–0.66), respectively, compared with nonexerciser (p < .05).
Doing physical exercise can decrease the risk of CAD, and exercising in the afternoon or evening may have more significant effects on the prevention of CAD than in other time of day.
Hamid Najafipour, Masoomeh Kahnooji, Mohammad Reza Baneshi, Mahboobeh Yeganeh, Milad Ahmadi Gohari, Mitra Shadkam Farokhi and Ali Mirzazadeh
population in the 15- to 75-year age group in 2012 (Kerman Coronary Artery Disease Risk Factor Study [KERCADRS]: phase 1) showed that about 39% of men and 45% of women had LPA. 12 Another study examined changes in PA over time and reported that prevalence of LPA in Tehran reduced from 45.9% in 2002–2005 to
John S. Green, Peter W. Grandjean, Shelly Weise, Stephen F. Crouse and J. James Rohack
Although endurance exercise and supplemental estrogen have both been shown to improve serum lipid cardiac risk profiles in postmenopausal women, data regarding a possible synergistic influence are scarce and inconsistent. The purpose of this study was to determine whether such a synergistic influence could be demonstrated. Serum concentrations of total cholesterol (TC), HDL-cholesterol (HDL-C), HDL2-C, HDL3-C, LDL-C, and triglycerides (TG) were obtained from postmenopausal women (N = 45) in each of 4 groups: currently exercising and taking estrogen replacement, exercising and not taking estrogen, sedentary and taking estrogen, and sedentary and not taking estrogen. HDL-C was on average 21% higher (p < .05) and the HDL-C:LDL-C ratio on average 45% higher (p < .05) in the exercise-plus-estrogen group than in any of the other 3 groups. It was concluded that the combination of endurance exercise and estrogen replacement might be associated with better lipid coronary risk profiles in postmenopausal women than either intervention alone.
Darryn S. Willoughby, Mark Roozen and Randall Barnes
This study attempted to determine the effects of 12-week low- and high-intensity aerobic exercise programs on functional capacity and cardiovascular efficiency of elderly post-coronary artery bypass graft (CABG) patients. Time (Timemax). estimated maximum VO2 (VO2max), heart rate (HRmax), systolic blood pressure(SBPmax), estimated mean arterial blood pressure (MABPmax), and rate × pressure product (RPPmax) were assessed during graded exercise tests before and after 12 weeks of low-intensity (65% HRmax) and high-intensity (85% HRmax) exercise. Subjects (n = 92) were placed in either a low-intensity (LIEX), high-intensity (HIEX), or nonexercising control group (CON). LIEX and HIEX showed increases from pre- to postprogram for Timemax and VO2max. LIEX and HIEX showed decreases for SBPmax, MABPmax, and RPPmax. HIEX and LIEX produced greater improvements than CON for these four variables, while HIEX was superior to LIEX. It was concluded that 12 weeks of low- and high-intensity aerobic exercise can increase functional capacity and cardiovascular efficiency in elderly post-CABG patients; however, high-intensity exercise may produce greater improvements than low-intensity exercise.
Ming-Lang Tseng, Chien-Chang Ho, Shih-Chang Chen, Yi-Chia Huang, Cheng-Hsiu Lai and Yung-Po Liaw
Evidence suggests that physical activity has a beneficial effect of elevated high-density lipoprotein cholesterol (HDL-C) on reducing coronary artery risk. However, previous studies show contrasting results for this association between different types of exercise training (i.e., aerobic, resistance, or combined aerobic and resistance training). The aim of this study was to determine which type of exercise training is more effective in increasing HDL-C levels. Forty obese men, age 18–29 yr, were randomized into 4 groups: an aerobic-training group (n = 10), a resistance-training group (n = 10), a combined-exercise-training group (n = 10), and a control group (n = 10). After a 12-wk exercise program, anthropometrics, blood biochemical variables, and physical-fitness components were compared with the data obtained at the baseline. Multiple-regression analysis was used to evaluate the association between different types of exercise training and changes in HDL-C while adjusting for potential confounders. The results showed that with the control group as the comparator, the effects of combined-exercise training (β = 4.17, p < .0001), aerobic training (β = 3.65, p < .0001), and resistance training (β = 2.10, p = .0001) were positively associated with increase in HDL-C after adjusting for potential confounders. Our findings suggested that a short-term exercise program can play an important role in increasing HDL-C levels; either aerobic or resistance training alone significantly increases the HDL-C levels, but the improvements are greatest with combined aerobic and resistance training.
Christian C. Evans and Sandra L. Cassady
To describe the underlying conditions that predispose athletes to sudden cardiac death (SCD) and review signs and symptoms that indicate an athlete is at risk.
MEDLINE, the Los Angeles Times and Triathlon Times archives, and other sources identified in the references of articles initially located therein. A total of 43 references were included.
Most cases of SCD in younger athletes (≤35 years) are attributable to multiple hereditary conditions, with familial hyper-trophic cardiomyopathy being the primary cause, whereas the major cause of SCD in older athletes (>35 years) is coronary artery disease. Health-care professionals evaluating athletes should pay particular attention to past medical and family history. Items in an athlete’s screening that suggest increased risk include a history of chest pain, syncope, excessive shortness of breath, irregular heart rate or murmur, or a history of SCD in an immediate family member.
Peter T. Katzmarzyk
Although the prevalence of physical inactivity is high in Canada, few studies have assessed its public health impact.
A cause-deleted methodology was employed to estimate the effects of physical inactivity on life expectancy. Life expectancy in 2002 was estimated from an abridged life table analysis, which was repeated after removing deaths from physical inactivity. Deaths from physical inactivity were estimated from published population-attributable fractions for coronary artery disease, stroke, hypertension, colon cancer, breast cancer, and type 2 diabetes.
Life expectancy was 79.7 y in the total population, 77.2 y in males, and 82.1 y in females. Compared to overall life expectancy, physical inactivity cause-deleted values were 0.86 y lower in the total population, 0.65 y lower in males, and 1.0 y lower in females.
Life expectancy could be increased by over 10 months if Canadians could be encouraged to be physically active.
Han C.G. Kemper and Robbert Verschuur
The purpose of this longitudinal study was to identify factors for coronary artery disease (CAD) in a teenage population in the Netherlands from ages 13.5 to 21.5 years. In a follow-up study 93 boys and 107 girls were measured annually from 1977 to 1980, and a fifth measurement was made in 1985. The CAD factors assessed were total serum cholesterol (TC), high density lipoprotein cholesterol (HDL), TC/HDL ratio, systolic (Psyst) and diastolic (Pdiast) blood pressure, percentage body fat (percent fat) and aerobic fitness (VO2 max/BW). The results indicate that the percentage of subjects at risk for CAD are relatively low in both sexes for all factors except for percent fat. From 20 to 30% of the subjects remain in the upper half of risk factor distribution throughout the 8 years study for TC, TC/HDL, percent fat, and VO2max/BW, indicating stability during the teenage period. Because percent fat combines a high stability with relatively high mean values during the teenage period in both sexes, this parameter seems a particularly important CAD risk factor in youngsters.
Serina A. Neumann, Jessica R.P. Brown, Shari R. Waldstein and Leslie I. Katzel
Silent myocardial ischemia (SI) has been linked to increased risk of future coronary events. Enhanced systolic and diastolic blood pressure (SBP and DBP, respectively) and heart-rate (HR) reactions to stress (cardiovascular reactivity [CVR]) have been associated with greater severity of SI and are related prospectively to coronary-artery-disease endpoints. The authors examined the potential attenuating effects of 6 months of walking (aerobic exercise) versus control on CVR to three laboratory stressors in 25 older adults with exercise-induced SI. Maximal aerobic capacity was significantly improved by 12% for the exercise group and decreased by 8% for controls (p < .001). Groups had similar biomedical profiles pre- and postintervention. Walkers had significantly reduced DBP reactivity (pre, 12 ± 2; post, 4 ± 2 mm Hg) compared with controls (pre, 10 ± 2; post, 11 ± 2 mm Hg; p = .05), but no differences between groups were found for SBP or HR reactivity. These findings are the first to suggest that increased physical activity (via walking) can attenuate BP reactivity to emotional stressors in apparently healthy older adults with SI.