In a recent study published in the Journal of the American College of Cardiology, researchers investigated the sex-specific all-cause and cardiovascular mortality risk reductions derived from physical activity. They used a large (n = 412,313) cohort American cohort to identify this association and found that women derived greater benefits than their male counterparts from equivalent amounts of physical activity.
Historically, however, women have generally lagged men in exercise engagement. These findings may help inform clinicians and the health-minded of the advantages of physical exercise in combatting chronic cardiovascular disease (CVD) and bridge observed “gender gaps” by encouraging women to take up leisure-time physical activity.
Study: Sex Differences in Association of Physical Activity With All-Cause and Cardiovascular Mortality.
The gender gap and what this means for sex-specific cardiac health
Cardiovascular mortality remains one of the leading causes of global human loss of life, alarmingly a likely underestimation when considering that cardiovascular disease (CVD) is a commonly reported comorbidity in numerous non-transmissible and transmissible pathologies. Decades of research have revealed that physical activity (PA) can substantially reduce all-cause and cardiovascular mortality, but records reveal that public involvement in leisure time PA is sorely lacking.
In the United States of America (US) alone, fewer than 25% of citizens meet the minimum PA recommendations of 150 min/wk. of moderate PA or 75 min/wk. of vigorous PA prescribed by the US Centers for Disease Control and Prevention (CDC) and the American College of Cardiology. Significant inter-sex differences in PA engagement further skew these already suboptimal observations – a substantially larger proportion of men are known to engage in leisuretime PA than women, which, when combined with differences in physiological responses, exercise capacities, and activity tolerances between the sexes, might result in significantly different mortality outcomes between these cohorts.
Unfortunately, the empirical outcomes of these “gender gaps” between men and women have never been tested within a scientific framework, denying clinicians, policymakers, and the health conscious of the information they need to optimize PA-related outcomes. Understanding the role of sex in these associations would allow for improved guidelines aimed at bridging the gender gap, fostering increased female PA engagement, and reducing overall mortality risk.
About the study
In the present study, researchers aimed to elucidate if PA-derived health benefits differ depending on the sex of the PA-engaging individual. Their cohort was derived from the National Health Interview Survey (NHIS), a large-scale collaboratory effort carried out by the CDC and the National Center for Health Statistics. Established in 1957, the NHIS is a prospective cohort maintaining health records of Americans across 50 states and the District of Columbia, representing a proxy for America’s health.
The current study used participant data from 1997 to 2017 and was initially comprised of 646,279 individuals. Excluding participants with severe cardiovascular conditions (e.g., coronary heart disease), cancers, or missing demographic or medical data resulted in a final cohort of 412,413 adults. Data collection included demographic and medical information (from the NHIS database) and a consistent, standardized questionnaire for PA frequency, duration, and type assessment, presented at both baseline and follow-up evaluations.
Cox proportional hazard regression models corrected from demographic and clinical covariates were used to assess primary outcomes. Likelihood ratio tests were used to compute sex-specific differences in outcome estimates.
Study findings
Demographic data collation revealed that 54.7% of included participants were women, more than 68% of whom were of White ethnicity. The average age of the study cohort was 43.9 years, and the study collected a total of 4,911,178 person-years of follow-up data. During the course of the study, 39,935 participants died from all causes, 11,670 of which were cardiovascular.
Previously observed discrepancies in sex-specific PA engagement were validated in this study, with only 32.5% of women engaging in weekly aerobic PA compared to 43.1% of male participants. Every PA metric measured in the survey revealed greater male engagement than female, with 15.2% of men achieving the prescription weekly PA goal of 150 min/wk. In contrast, only 10.3% of women met this goal.
However, hazard analyses present that the few women who do engage in physical activity derive far greater relative health benefits than their male counterparts. Compared to inactivity, female PA engagement results in a 24% risk reduction (all-cause mortality), while equivalent PA engagement in men only decreased their mortality risk by 15%.
“In dose-dependent analyses for the entire cohort, the benefit of PA on all-cause mortality peaked at ∼300 min/wk of MVPA and then plateaued. The greatest mortality benefit in men was achieved at 300 min/wk of MVPA with an 18% lower hazard in all-cause mortality. Women derived a similar magnitude of benefit at 140 min/wk of MVPA, and continued to benefit with increasing min/wk of MVPA until the greatest benefit of 24% lower hazard (HR: 0.76; 95% CI: 0.72-0.80) was achieved at ∼300 min/wk.”
While these findings do require validation in non-American cohorts, where observed results, especially those pertaining to engagement, might vary drastically from those observed herein, this study highlights the profound benefits of PA engagement for both sexes and may play a crucial role in motivating traditionally hesitant women to take up these activities given the health rewards they provide.
