Lifting weights is often associated with building stronger muscles, but new research suggests it may also help protect the heart.
A large study published in JACC found that women who regularly performed resistance training were less likely to develop major cardiovascular disease, especially heart attacks. The research also showed that the healthiest women were not simply those who exercised more, but those who combined different healthy movement habits throughout the week.
Heart disease continues to be the world’s leading cause of death. High blood pressure, high cholesterol, diabetes, obesity, smoking, and lack of physical activity all increase the risk. Doctors have long advised adults to perform at least 150 minutes of moderate exercise every week, but strength training has often received less attention despite its many benefits.
Strength training involves making muscles work against resistance. This may include lifting dumbbells, using gym equipment, resistance bands, or body-weight exercises. In addition to increasing muscle strength, it helps maintain bone density, improves balance, and supports healthy aging.
Scientists led by Dr. Tianyue Zhang examined data from more than 117,000 women participating in two famous long-term health studies in the United States. The researchers compared weekly strength training, aerobic exercise, and television viewing with future heart disease outcomes.
Women completing two or more hours of resistance training each week experienced substantially lower rates of major cardiovascular disease than women who performed none. The greatest benefit was seen for heart attacks, with risk reduced by 44 percent. Every extra hour of resistance exercise each week provided additional protection.
The biggest health gains occurred when strength training was combined with regular aerobic activity such as walking or cycling. Women who met exercise recommendations and also spent less time sitting in front of the television had the lowest risk of heart disease, stroke, and heart attack.
These findings suggest that healthy movement throughout the day is more important than relying on a single activity. Limiting long periods of sitting may be nearly as important as adding exercise sessions.
The researchers also found that the protective effects remained after accounting for several health conditions, although they became slightly smaller. This indicates that weight training may help through several different pathways, including improving blood sugar control, body composition, and blood vessel health.
There are some important limitations. Participants reported their own exercise habits, which may not always be perfectly accurate. Most participants were health professionals, so the results may not represent every population.
Because the study observed people rather than assigning exercise programs, it cannot prove that resistance training directly prevented heart disease.
Still, the evidence strongly supports including strength exercises alongside aerobic activity as part of a healthy lifestyle. Current exercise guidelines recommending at least two strength-training sessions each week appear well supported by these findings.
Study review and analysis: This was a high-quality prospective cohort study with an exceptionally large sample and long follow-up period. The consistent findings across two cohorts strengthen confidence in the results.
Although randomized clinical trials would provide stronger evidence of cause and effect, the study offers compelling support for resistance training as an important part of cardiovascular disease prevention for women.
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Source: Harvard T.H. Chan School of Public Health.
