A new study published in the JACC journal suggests that women who engage in strength training may experience a reduced risk of major cardiovascular events, particularly when combined with aerobic exercises. The findings indicate that cardiovascular health is better understood by examining overall movement patterns rather than focusing solely on individual activities, and that strength training can offer additional health benefits when integrated into an active lifestyle.
Cardiovascular diseases (CVDs) remain the leading cause of mortality globally, making accessible prevention strategies more crucial than ever. Aerobic activities, such as brisk walking, jogging, cycling, and swimming, are well-established as effective in preventing CVDs. Strength training (ST), also known as resistance training, is less commonly emphasized. It involves working muscles against a force, such as one’s own body weight, free weights, elastic bands, or weight machines.
Currently, it is recommended in the US to engage in at least two days of ST per week and 150 minutes of moderate-to-vigorous intensity aerobic activity. The importance of limiting sedentary behavior, including prolonged TV viewing, which is now an independent risk factor for CVD, is also highlighted. This study investigates how ST influences the risk of CVD within a broader prevention framework.
“Despite their proven health benefits, strength training exercises are often overlooked as a CVD prevention strategy, and their impact on CVD risk, particularly among middle-aged and older women, remains understudied,” states lead author Tae-Yuan Zhang, from the T.H. Chan School of Public Health at Harvard. “The key question is how beneficial they are beyond just aerobic activity alone?”
The researchers analyzed a prospective cohort of 117,025 women from the Nurses’ Health Study (NHS) and NHS II, with mean ages at baseline of 66.8 and 48.1 years, respectively. Exercise duration was assessed every four years and self-reported separately for upper and lower body. The primary measure of sedentary behavior was TV viewing time, reported as the average weekly hours spent sitting at home watching TV.
The primary outcome assessed was the incidence of major CVD, defined as nonfatal or fatal myocardial infarction (MI), stroke, coronary artery bypass grafting, or percutaneous coronary intervention (PCI).
In both cohorts, higher levels of ST were associated with a lower risk of major CVD, particularly MI, with no significant association observed for stroke. Women engaging in two or more hours of ST per week had a 20% lower risk of major CVD and a 44% lower risk of MI compared to women who did not engage in ST. Each additional weekly hour was linked to a 5% reduction in major CVD risk and a 14% reduction in MI risk.
After adjusting for BMI and cardiometabolic conditions such as diabetes, high blood pressure, and high cholesterol, these associations were somewhat attenuated but remained evident.
ST provided additive benefits even among women who also engaged in aerobic exercise. In this subgroup, women who performed two or more hours of ST weekly in addition to 150 minutes of aerobic exercise per week had a 45% lower risk of MI compared to those who were physically inactive, while the association with major CVD was somewhat altered.
In a comprehensive analysis of movement patterns considering exercise duration, aerobic exercise, and TV viewing time, women who met all three recommendations were found to have the lowest risk of major CVD, MI, and stroke compared to those who met only some or none of the recommendations.
“These findings suggest that within an already active population, strength training is associated with an additional reduction in CVD risk beyond overall aerobic activity,” Zhang explains. “Along with aerobic activity and reducing sedentary behavior, strength training can be an important component of public health strategies for CVD prevention in women.”
Limitations of the study include reliance on self-reported data for ST, potential influence of unmeasured confounders, and limited diversity of participants. Additionally, the researchers could not fully disentangle the impact of the type of ST performed from the overall volume of ST completed by participants.
“We have long advocated for strength training, and this study provides robust evidence supporting that recommendation,” the study authors concluded. “It should be incorporated into a balanced wellness program to maintain function and longevity.”
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