For CHD Patients, Physical Activity More Meaningful Than Weight Changes Over Time

Patients with coronary heart disease (CHD) stand to gain a survival benefit from getting regular physical activity, no matter if it’s of low or high intensity, according to 30-year data from a Norwegian registry study. As in prior reports, weight loss was linked to an increase in the risk of death among normal-weight individuals with CHD, but in a surprising twist, weight gain over the years didn’t seem to matter.

It may be tempting to walk away from those findings with the idea that putting on weight isn’t a bad thing. Indeed, “it is normal to gain a few pounds/kilos over the years,” first author Trine Moholdt, PhD (Norwegian University of Science and Technology, Trondheim, Norway), told TCTMD. And while exercising to intentionally lose weight can be helpful, she said via email, “I think that the take-home message from our study, and from most of the research done on the effects of exercise and physical activity, is that the most important benefits of exercise do not include weight loss.”

For Moholdt, the news on physical activity is more compelling, in that independent of weight fluctuations, the “findings show that even if you have been inactive so far, it is never too late to start.”

Clinicians on the whole need to pay more attention to physical activity, Moholdt advised. “There is a great need for better education of health personnel about the benefits of exercise training,” she stressed, adding, “Cardiorespiratory fitness is a strong and independent marker for survival, and it is time we take this into clinical practice as a vital sign.”

Moholdt and colleagues published their findings online ahead of the March 13, 2018, issue of the Journal of the American College of Cardiology.

This study “is supportive of other research that shows physical activity and exercise capacity are very strong predictors of long-term survival in people with coronary disease,” Randal J. Thomas, MD (Mayo Clinic, Rochester, MN), commented. Data from Olmsted County, the area near his hospital, have shown that participating in cardiac rehab after PCI or CABG can halve the risk of dying within 5 to 10 years, he noted.

Altogether, the body of evidence is “pretty powerful and gives us good ammunition to use as we counsel our patients to exercise more and more and try to keep healthy,” Thomas said, emphasizing that it’s important to sustain the activity over time. “Some patients have the idea that if they exercise for a few weeks after their event, then they’re okay and they’re cured. And they go back to their old way of living.”

Cardiorespiratory fitness is a strong and independent marker for survival, and it is time we take this into clinical practice as a vital sign. Trine Moholdt

Moholdt, along with Carl J. Lavie, MD (John Ochsner Heart and Vascular Institute, New Orleans, LA), and Javaid Nauman, PhD (Norwegian University of Science and Technology), looked at patterns in body weight and physical activity for 3,307 individuals (32% women) with angina or prior MI enrolled in the Nord-Trøndelag Health Study, known as HUNT. Subjects were examined at two out of three time points—1985, 1996, and 2007—with follow-up lasting until 2014 (median 15.7 years). During the 30-year period, 1,493 of them died.

Study participants who got some level of physical activity were at a lower risk of all-cause death compared with those who reported being inactive. This protective effect of exercise was seen regardless of whether individuals achieved recommended activity levels (adjusted HR 0.64; 95% CI 0.50-0.83) or did not (adjusted HR 0.81; 95% CI 0.67-0.97). It also was apparent in those who shifted from the high to low groups, so long as they got some activity (adjusted HR 0.74; 0.60-0.92), and the benefit remained when researchers took weight changes into account.

Additionally, independent of the effects of exercise, people losing 0.10 kg/m2/year were at higher risk of all-cause death (adjusted HR 1.27; 95% CI 1.10-1.47) and CV death (adjusted HR 1.34; 95% 1.11-1.63). Yet those who gained 0.10 kg/m2/year saw no significant shift in their likelihood of dying.

‘Really Tricky’ to Interpret Weight Changes

When the researchers stratified participants based on whether they were at normal weight or were overweight or obese, differences emerged. Those who had a normal body mass index (BMI) followed the above patterns: increased risk with weight loss and decreased risk with weight gain. But “we were surprised that we didn’t see an increased risk associated with weight gain in those who were already overweight or obese at baseline,” Moholdt said.

“An important limitation of our study is that we did not know the reasons for changes in weight over the years, more specifically whether the weight loss was intentional or not,” she continued.

Thomas also noted that “weight studies are really tricky,” because the cohorts can include not only people who lost weight because they were sick but other types of individuals. “You’ve got some people who may be gaining muscle weight, [since] they’re doing more exercise. You may have some people who are gaining fat weight,” he explained. “So, it’s all kind of mingled together.”

Writing in an editorial, Claude Bouchard, PhD (Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge), agrees that the HUNT analysis “contributes important new information on the central question of whether long-term changes in body weight and [physical activity] level influence mortality rates after a CHD event.”

But he questions how these shifts were quantified, specifically the use of BMI to track weight changes and the use of questionnaires to assess physical activity.

Without doing further calculations, it is difficult to envision what these shifts in BMI entail, Bouchard says. He does the math using baseline height and weight data from HUNT—0.10 kg/m2/year translates into at least 9 kg (approximately 20 pounds) gained over 30 years. “Such large body weight excursions are likely accompanied by higher total adiposity, visceral fat deposition, and ectopic fat accumulation,” which paradoxically indicates that not all weight gain is atherogenic, he says.

Regarding physical activity, people tend to overestimate how much they’re actually getting, and in HUNT in particular, the questions they were asked changed across the three waves, Bouchard notes. All that said, “the findings add to the body of data suggesting that promoting regular [physical activity] in CHD patients is likely to save lives,” he agrees.