Can Strength Training Improve Chronic Disease Outcomes?

Women can reduce their risk of diabetes and other chronic conditions simply by incorporating resistance exercise into a weekly physical activity plan, according to the National Institute on Aging.

With Eric J Shiroma Jr, ScD, MEd and Caroline Apovian, MD

The recommendation that adults aim for 2-1/2 hours of cumulative moderate to vigorous physical activity weekly to achieve overall health and ward off chronic diseases such as diabetes, cardiovascular disease, and obesity has been in place since the release of the Physical Activity Guidelines for Americans.1

Less attention, however, has been paid to any beneficial effects achieved by regular resistance training despite the strong recommendation to alternate cardio workouts with strength-building exercises for all muscle groups.1   

Strength training, done regularly, appears to lower risk of diabetes.

A new study,2 published by experts at the National Institute on Aging (NIA) in Washington, DC and Harvard Medical School in Boston, MA affirms the clinical advantages of including strength training as an integral part of a weekly workout plan to gain the greatest health advantages.           

Regular Strength Training Lessens Diabetes, CVD

The researchers determined that the women in this study, averaging 62.6 years, who did any type of regular strength training achieved a 30 percent reduction in the incidence of type 2 diabetes (T2D). Additionally, their risk of developing cardiovascular disease dropped by 17 percent.

As might be expected, the women who engaged in a combination of strength training and aerobic activity seemed to be the healthiest. In fact, women who consistently completed strength training and accomplished at least 120 minutes of aerobic activity weekly had a 65 percent lower risk of T2D than women who did no exercise at all. Women who achieved at least 120 minutes a week of aerobic exercise but no strength training had a 48 percent risk reduction.

“This benefit [of strength training] is seen even when you consider how much other exercise is being done,” Eric J. Shiroma, Jr., ScD, MEd, the lead study author and a staff scientist at NIA and an author of the study, told EndocrineWeb. “In fact, for the same total amount of exercise, those who participated in both strength training and aerobic activity had a lower risk than those who participated in only strength or only aerobic activity. This would suggest that dedicating some activity time to each domain could reduce risks further than simply doing one.”   

Resistance Training Improves Insulin Sensitivity

“Sarcopenia causes insulin resistance, even in nondiabetics,” said Caroline Apovian, MD, FACP, FACN, director of the Nutrition and Weight management Program at Boston Medical Center in Boston, “making it very important to maintain your muscle mass as long as you can.”

Lifting weights and doing resistance training enables muscles to have a better insulin-stimulated glucose-intake response, which translates into more glycemic control for people with diabetics, Dr. Apovian told EndocrineWeb.

The findings from the Women’s Health Study lend further support to the role of muscle-toning workouts as an essential part of a physical activity regimen, particularly when the goal is to achieve a reduction in the risks of T2D and CVD, and lends further evidence of the role of strength training independent of aerobic-type exercise.

For example, in 2010, Louisiana State University scientists determined that resistance training and aerobic training together improved participants’ levels of Hemoglobin A1c; this group also shed body weight at a rate more than twice the rate of those who engaged in either aerobic activity or strength training, but not both.3

A 2014 Harvard School of Public Health study4 reported a reduction in rates of T2D from 12 to 35 percent in both men and women who regularly lifted weights. And, a 2015 study5 conducted at the University of South Carolina found that women who did strength training had lower rates of cardiovascular risk factors such as body fat, total cholesterol, and fasting glucose.

Time to Prescribe Resistance Training for Your Patients

Dr. Apovian has made it a routine practice to discuss the benefits of strength training with all of her patients who either have, or are at risk of, T2D, CVD and obesity, and she recommends all clinicians working with these types of patients to do the same.

The NIA has a very useful handout that you can make available in your waiting room and post in examination rooms to promote the discussion.

Dr. Apovian also offered some tips that you can share with patients who may be resistant to a suggestion that they incorporate strength training into a weekly physical activity plan: 

Stress that strength training can help improve her glucose levels, leading to less reliance on diabetes medications.

Be prepared to challenge the “weight-lifter” stigma.

“It’s not about bulk,” Dr. Apovian said, “We’re restoring the functionality of the muscle and giving the muscle back strength.”

Provide a specific activity regimen for your patients. Dr. Apovian, for example, recommends that her patients begin adding strength training twice a week, alternating with at least 5 days of cardio exercise, even if its just walking. 

In addition, here are a few more recommendations for clinicians to consider:

  • Ensure that patients do a full-body workout comprised of leg presses, leg extensions, leg curls, chest presses, seated rowing, pulldowns, bicep and tricep curls, and sit ups for their abdominals.
  • Suggest they join a gym that offers resistance machines or strength-building classes; they can work individually with a trainer or they can purchase inexpensive weights and resistance bands to use at home.
  • Most importantly, offer encouragement to get them started and then offer ongoing motivation so they will stay active. 

Dr. Apovian cautioned that "getting patients to add resistance training is important given these findings, but it's not enough. Working with a trainer is the most relaxed way for a patient to get started" but she conceded that it is an expensive option that won’t work for all women. For patients on a budget, she suggested a session or two with a fitness trainer who could design a program that the patient could follow at home.

“Patients can’t compensate for physical inactivity,” stressed Dr. Apovian. “They still need to make sure they’re moving throughout the day.” In other words, an hour at the gym doesn’t give anyone license to sit for the rest of the afternoon. So suggest that your patients download a pedometer app and aim for at least 10,000 steps a day. 

To gain more insight into the types of exercises that will most benefit your patients, a very useful guide to strength training for seniors is available from Harvard Medical School. To view it, click here

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