Strength training is for gaining muscle strength and size and aerobic exercise is for heart health, right? Not so fast! That’s the conventional way of looking at these two forms of exercise. But a new study questions this tenet. In fact, this study suggests that strength training may be more protective to your heart than aerobic exercise.
Strength Training and Heart Health: What the Study Showed
Researchers used data from a large trial called the National Health and Nutrition Examination Survey (NHANES) that began in 2005. In the study, researchers looked at the exercise habits and cardiovascular risk factors of over 4000 adults in the United States. As you might expect, most of the Americans in the study didn’t exercise regularly and the number that did dropped off with age. Between the ages of 21 and 44, 28% of the adults did aerobic-type exercise and 36% did some form of strength training. In the age group over 45, only 21% did aerobic exercise and 25% performed strength training.
When the researchers looked at cardiovascular risk factors and compared them to the subjects’ exercise habits, they came to a surprising conclusion. Both forms of exercise reduced cardiovascular disease risk factors by 30% to 70%, but the link was stronger for strength training. Those who strength trained were less likely to have a risk factor for cardiovascular disease. Risk factors for heart disease include obesity, high blood pressure, diabetes, and abnormal lipids. The odds were also lower with aerobic exercise, although the link wasn’t as strong as it was for strength training.
Keep in mind that this is a correlational study. It doesn’t necessarily say that strength training was the reason the participants were less likely to have a cardiovascular risk factor. There may be some other factor that people who strength train share in common that explains this association. It also doesn’t say that aerobic exercise isn’t effective for heart disease prevention. It just shows, strength training had a slight edge over aerobic exercise for reducing the risk. Also, keep in mind, the study didn’t specifically look at high-intensity cardiovascular exercise. There’s some evidence that intense exercise is more protective against cardiovascular disease than low to moderate-intensity aerobic exercise.
At the very least, this research suggests that strength training is important for heart health too. And, when you consider the other health and fitness benefits, like reduced risk of frailty, greater mobility, less loss of muscle mass, and better balance, strength training is no less valuable than a cardiovascular workout. The conclusion? Health care professionals should tell patients to do more than walk – they should encourage strength training too! The results of this study were presented at the American College of Cardiology Latin America Conference 2018. So, hopefully, health care professionals will get the message!
How Can You Explain These Results?
By now, you might wonder how strength training protects against heart disease. One observation from the study is that strength training was linked with a lower risk of type 2 diabetes and a reduction in the risk of being overweight in both the younger and older participants. Dynamic exercise, like aerobic training, was also associated with a reduced risk of type 2 diabetes and being overweight. However, the link was stronger in those who strength trained, particularly in the younger age group. The study failed to show a correlation between strength training or aerobic exercise and a reduced risk of hypertension or lipid abnormalities, two established risk factors for cardiovascular disease. So, the way both forms of exercise reduce risk is primarily by lowering the risk of obesity and type 2 diabetes.
But why does strength training have an edge, especially in the younger age group? The researchers surmise that intensity may be a factor. Many adults, particularly older ones, walk as a form of aerobic exercise. But most walk at a low to moderate intensity. In contrast, strength training is by its nature intense. It’s hard to do a low-intensity strength training workout. More vigorous exercise burns more calories and may improve how the body handles glucose better than a less intense workout.
Better Blood Vessel Function?
Another way strength training may lower cardiovascular risk is by improving how blood vessels function. In one study, researchers looked at the blood vessel response to 45 minutes of resistance training and aerobic exercise. After each workout, the researchers used a technique called flow-mediated dilation to look at blood vessel function. They found that resistance training led to a slight increase in stiffness of the arteries but also boosted blood delivery to the periphery of the body.
In contrast, aerobic training decreased the stiffness of the arteries but didn’t increase blood flow to the periphery. The resistance training group also experienced a drop in blood pressure that lasted longer than the aerobic exercise group. Both a boost in blood flow to the periphery and a reduction in stiffness of the arteries is favorable for cardiovascular health. So, resistance training and aerobic activity have positive, but slightly different, effects on blood vessel function.
Other research shows that strength training may help with blood pressure control as well. In one small study, 12 weeks of weight training, 3 times weekly, was linked with a reduction in blood pressure 16 mm Hg systolic and 12 mm Hg diastolic in men with hypertension. Be aware that blood pressure can rise during weight training but usually falls back to normal rapidly after lifting is over. Talk to your physician before weight training if you have significant high blood pressure or blood pressure that’s poorly controlled.
The Bottom Line
Don’t stop doing aerobic exercise! There’s too much evidence that it lowers the risk of cardiovascular disease by multiple mechanisms. But don’t assume that strength training is just for your muscles. It’s good for your heart too. It seems to work primarily by lowering the risk of type 2 diabetes and obesity, two strong risk factors for heart disease. It also may improve oxygen delivery and lower blood pressure. Make sure strength training AND aerobic exercise is part of your routine. They both matter!
Medscape Family Medicine. “Strength Training May Best Aerobics for Cardioprotection”
Men’s Journal. “Get Heart Healthy by Lifting Weights”
Medical News Today. “Weight Training Has Unique Heart Benefits, Study Suggests”
Heart Insight Magazine. “Can Strength Training Help with Blood Pressure?”
Resperate.com. “Can Strength Training Help with Blood Pressure?”
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