Weight training - pumping iron and the like - is good for the heart, even in amounts less than conventionally recommended.
It's especially recommended for heart-healthy older people.
The advisory, to be published in the Journal of the American Heart Association, is based on surveys of the medical literature by separate groups headed by Franklin and Kelley.
"The heart association asked an expert panel led by me to review the scientific literature on the safety, benefits and rationale of weightlifting," says Franklin.
"We came to five major conclusions about resistance training.
"The first is that weight training can favourably modify many risk factors associated with heart disease - cholesterol levels, blood pressure, body structure and glucose metabolism. The second is that weight training improves cardiovascular function. If the muscles are stronger, there is less of a rise in heart rate and blood pressure during lifting. The third is that it is beneficial for persons who are watching their waistline and is underused in weight control or reduction programs.
"The fourth is that a three- or four-month program can give major improvements in strength and endurance. Finally, we found that weight training is especially beneficial for older persons, 65 to 70 years of age. It promotes independent living and increases bone density, which is especially important for older women."
The study led by Kelley, who is director of the meta-analytic research laboratory in the Northern Illinois University department of kinesiology and physical education, was more limited, looking only at the effects of weight training on blood pressure.
Weighting down blood pressure
"We looked through 11 700 studies to find 11 of them that were appropriate," says Kelley.
"They compared 182 subjects who exercised with 138 controls. We found a clinically important reduction in blood pressure - 2% in systolic pressure [when the heart is beating], 4% in diastolic pressure [when the heart rests between beats]. Reductions even smaller than the ones we are reporting can reduce the risk of stroke and heart disease."
A relatively minimal schedule of weight training provides benefits, the heart association says - a single set of eight to 15 repetitions, using eight to 10 different exercises, two days a week. Traditionally, three sessions a week have been the norm, but studies show that "comparing one versus three, you get about 90% of the improvements just doing a single set," Franklin says.
The regimens don't require a gymnasium, he says. If you have a weight set or machine, you can do them at home. The exercises recommended include curls, chest pressing and rowing.
"Use a weight set that allows you to do a number of exercises at home," says Kelley.
The new recommendation is not meant to replace regular aerobic exercises such as swimming and brisk walking.
The important message is that weight training is complementary to, not a replacement for aerobic exercise. It offers things that aerobics doesn't.
Older people worried about the ill effects of weight training should know that studies find it extremely safe in healthy adults and low-risk cardiac patients, with some exceptions.
"Weight training in moderate- to high-risk persons requires additional study," Franklin says. "It is not recommended for people with unstable angina, uncontrolled high blood pressure, serious arrhythmias or severe valvular heart disease, or heart failure patients who have not been evaluated or effectively treated."
What To Do
Before you add weight training to your exercise regimen, ask your doctor if any condition might interfere with the training and then seek advice about the best and most convenient forms of exercise.
You needn't want to be Arnold Schwarzenegger to benefit from weight training. Franklin says any weight that, after 10 or 15 repetitions, leaves you comfortably fatigued will work. In addition to curls, you can do military presses (over your head), leg presses, rowing and calf raises (where the weight is on your shoulders and you stand tiptoe).
Photo: Dumbbell from Shutterstock
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