Is cutting calories enough to keep your heart healthy?

Using moderate exercise a day to burn 250 calories is more effective than exercise alone for older adults classed as obese, according to a new study. Combining aerobic exercise with a moderate reduction in daily calories resulted in greater improvements in aortic stiffness (a measure of vascular health), compared to exercise only or to exercise plus a more restrictive diet, says new research published today in the journal Circulation.

Despite aerobic exercise being measured favourable in relation to aortic structure and function, previous studies have shown that exercise alone may not be sufficient to improve aortic stiffness in older adults with obesity.

The study assessed the effects of aerobic exercise on aerobic stiffness, with and without reducing calories and “was measured via cardiovascular magnetic resonance imaging (CMR) to obtain detailed images of the aorta,” said lead author of the study, Tina E. Brinkley, PhD, associate professor of gerontology and geriatric medicine at the Sticht Center for Healthy Aging and Alzheimer’s Prevention at Wake Forest School of Medicine, North Carolina.

“We sought to determine whether adding caloric restriction for weight loss would lead to greater improvements in vascular health compared to aerobic exercise alone in older adults with obesity,” she explained.

The randomised controlled trial included 160 clinically obese, inactive adults with age ranges of 65-79. The participants were a part of one of three intervention groups which lasted for 20 weeks – randomly assigned. Group one would experience exercise only and consume a regular diet, group two would both adopt an exercise regime and a moderate calorie restricted diet, and group three would consume an intensive calorie restricted diet along with sufficient exercise.

The structure and function of the aorta was assessed with CMR, measuring the aortic arch pulse wave velocity (PWV) – the speed at which blood travels through the aorta – and its ability to expand or contract.

The results found that a loss of nearly 10 percent in body weight or around 20 pounds – over the five-month study – signified improvements in aortic stiffness in those participants assigned to group two.

Brinkley believes that the findings are an indication that lifestyle changes, which increase aerobic activity and moderately decrease calorie intake, may help to improve vascular health.

“However, we were surprised to find that the group that reduced their calorie intake the most did not have any improvements in aortic stiffness, even though they had similar decreases in body weight and blood pressure as the participants with moderate calorie restriction,” she explained.

Brinkley added that the results imply a combination of exercise and modest calorie restriction is likely to maximise vascular health, “while also optimising weight loss and improvements in body composition and body fat distribution.”