Purpose: To investigate the effect of the menstrual cycle (MC) on exercise performance across the power-duration relationship (PDR). We hypothesized females would exhibit greater variability in the PDR across the MC than males across a similar timespan, with critical power (CP) and Work-prime (W') being lower during the early follicular phase than the late follicular and mid-luteal phases. Methods: Seven eumenorrheic, endurance-trained female adults performed multiple constant-load-to-task-failure and maximum-power tests at three time points across the MC (early follicular, late follicular, mid-luteal phases). Ten endurance-trained male adults performed the same tests approximately 10 days apart. Results: No differences across the PDR were observed between MC phases (CP: 186.74 ± 31.00 W, P = 0.955, CV = 0.81 ± 0.65 %) (W': 7,961.81 ± 2,537.68 J, P = 0.476, CV = 10.48 ± 3.06 %). CP was similar for male and female subjects (11.82 ± 1.42 W • kg−1 vs. 11.56 ± 1.51 W • kg−1, respectively) when controlling for leg lean mass. However, W' was larger (P = 0.047) for male subjects (617.28 ± 130.10 J • kg−1) than female subjects (490.03 ± 136.70 J • kg−1) when controlling for leg lean mass. Conclusion: MC phase does not need to be controlled when conducting aerobic endurance performance research on eumenorrheic female subjects without menstrual dysfunction. Nevertheless, several sex differences in the power-duration relationship exist, even after normalizing for body composition. Therefore, previous studies describing the physiology of exercise performance in male subjects may not perfectly describe that of female subjects.

Background Coronary heart disease (CHD), the leading cause of death worldwide, has declined in many affluent countries but it continues to rise in industrializing countries. Objective To quantify the relative contribution of the clinical and population strategies to the decline in CHD mortality in affluent countries. Design Meta-analysis of cross-sectional and prospective studies. Data sources PubMed and Web of Science from January 1, 1970 to December 31, 2019. Method We combined and analyzed data from 22 cross-sectional and prospective studies, representing 500 million people, to quantify the relative decline in CHD mortality attributable to the clinical strategy and population strategy. Result The population strategy accounted for 48% (range = 19 to 73%) of the decline in CHD deaths and the clinical strategy accounted for 42% (range = 25 to 56%), with moderate inconsistency of results across studies. Conclusion Since 1970, a larger fraction of the decline in CHD deaths in industrialized countries was attributable to reduction in CHD risk factors than medical care. Population strategies, which are more cost-effective than clinical strategies, are under-utilized.

No abstract

The peer review history is available in the Supporting Information section of this article (https://doi.org/10.1113/JP281900#support-information-section).Robert Hyldahl received his M.S. and Ph.D. at the University of Massachusetts Amherst, where he studied the molecular mechanisms of skeletal muscle damage and wasting under the mentorship of Dr. Priscilla Clarkson. He joined the faculty at Brigham Young University in 2012, where he is currently an associate professor. The overarching goal of his laboratory is to contribute to the development of clinical interventions to maintain skeletal muscle vitality through the lifespan by studying the biologic mechanisms that underlie muscle adaptation to stress (e.g. disuse, damage, exercise and injury) in healthy, aged or clinical populations. This project is aimed at identifying the potential benefits of using heat stress to mitigate the deleterious muscular and cardiovascular effects of limb disuse.

Background: Due to uncertainly of chronic headache status as a society health problem, this study was conducted to determine total prevalence of headache and related factors. Methods: In Tabari cohort study (TCS), a variety of demographic and clinical data were collected from individuals aged between 35 and 70 years using a standard questionnaire. The prevalence of chronic headache and the duration of the outcome were obtained through self-reported information. In statistical analysis, Chi-square and multivariate logistic regression tests were used to evaluate the association between outcome and risk factors. Results: 10255 adults living in Mazandaran, Sari, 4149 women and 6106 male, were included in this study. The total prevalence of chronic headache was 13% (12.3%-13.6%). Factors such as female gender (OR: 4.10; 95% CI: