Young Women Need Earlier Messaging on Physical Activity for Preventing Later CHD, Study Hints

For younger women, it’s not the type of physical activity that matters for heart health but rather how much exercise they get as a whole, according to observational data from the Nurses’ Health Study II. Even brisk walking is associated with a lower risk of coronary heart disease (CHD), and the benefit extends across the spectrum of body mass index.

“Young women don’t get the fact that they could be at risk later in life for heart disease,” Marla Mendelson, MD (Northwestern Memorial Hospital, Chicago, IL), who was not involved in the study, told TCTMD. “They think it is something they don't have to worry about until menopause. And particularly in women who have other risk factors that they can’t control—diabetes, family history, even familial high cholesterol. It is so important to get this message across, and start doing something as soon as possible.”

These findings, published in the July 26, 2016, issue of Circulation, come after two decades of stagnation in the once declining rates of CHD in younger women, according to the accompanying editorial by Erin Michos, MD, and Michael Blaha, MD (Johns Hopkins School of Medicine, Baltimore, MD). The editorialists point out that women ages 35 to 54 years have actually seen an increase in their baseline risk of developing CHD and dying from cardiovascular causes.

Measuring Exercise and Its Benefits

Beginning in 1991, researchers led by Andrea Chomistek, ScD (Indiana University Bloomington, IN), prospectively analyzed data from Nurses’ Health Study II on 97,230 women age 27 to 44. They found 544 cases of CHD during the 20 years of follow-up.

Every other year, the women taking part in Nurses’ Health Study II were sent questionnaires meant to capture any newly diagnosed diseases or changes in risk factors. Using their answers, the researchers then (at approximately 5-year intervals) were able to calculate each individual’s total leisure-time activity in metabolic equivalent of task (MET) hours per week. Moderate activity, which included brisk walking, outdoor work, and yoga, was defined as a MET value of at least 3 but less than 6. Vigorous activity, which included jogging, running, swimming, and tennis, was defined as greater than 6 MET.

After adjusting for potential confounders, women reporting the most physical activity (≥ 30 MET hours/week) were at 25% lower risk of CHD in comparison to those with the least activity (< 1 MET hour/week; P = 0.01). Women who said they got more than 15 MET hours of moderate activity on a weekly basis had a 33% lower risk of CHD compared with women who did not do any moderate activity (P = 0.01). Those engaging in vigorous activity for at least 15 MET hours per week had a 23% lower risk of CHD (P = 0.04).

Importantly, activity was beneficial no matter the person’s body mass index (P for interaction = 0.70).

Current American Heart Association guidelines recommend that adults get at least 150 minutes of moderate, aerobic activity (3-5.9 MET) or 75 minutes of vigorous, aerobic activity (≥6 MET) each week.

Getting Exercise Into Practice

The study shows that any kind of activity can have an impact, which should make it easier for patients and physicians to incorporate into overall health goals, according to Chomistek.

“We did find that moderate activity was just as beneficial as doing something more vigorous or strenuous,” she told TCTMD. “So, I think that one message that a physician might want to relay to patients, if you are currently doing nothing, you don’t necessarily have to join a gym or start training for a marathon or doing something super intense. Just getting out and walking can be beneficial.”

In the accompanying editorial, Michos and Blaha echo that sentiment, suggesting that physicians will want to use this information to explain how exercise in many forms can be helpful.

“Because patients may equate exercise with high-intensity activities, which may be intimidating to initiate, it is important for clinicians to emphasize to their patients the considerable gains from simple brisk walking or other moderate [physical activity] like gardening, ballroom dancing, or water aerobics,” they write.

The study also highlights that even inactive women who are either of normal weight or obese can decrease their risk of CHD just by starting to be physically active in some way. Despite all the evidence backing exercise, Mendelson said, it can be easy to forget to remind patients to do it.

“As cardiologists we’ve seen the devastating results of severe coronary artery disease and we’re pretty good at treating it, but sometimes we can run out of options,” she said, emphasizing that prevention is crucial. “Prevention should not just be for middle age men who are afraid of having the big one. It’s for everybody.”

Michael H. Wilson is the 2016 recipient of the Jason Kahn Fellowship in Medical Journalism.

Sources:

• Chomistek AK, Henschel B, Eliassen AH, et al. Frequency, type, and volume of leisure-time physical activity and risk of coronary heart disease in young women. Circulation. 2016;134:290-299.
• Michos ED, Blaha MJ. Encouraging young women to move more: linking physical activity in young adulthood to coronary risk in women. Circulation. 2016;134:300-303.

Related Stories:

• Sitting Pretty: Only Prolonged Sedentary Time Linked With Incident CVD Risk
• Nutrition and Physical Activity: The ‘Low-Hanging Fruit’ for Cardiologists Programmed to Prescribe Pills
• Even a Little Exercise Yields Big Benefits, but Harm Unlikely at High Activity Levels