No reason not to expand trials
A year of high-intensity interval training seemed to benefit obese middle-aged adults at a high risk of heart failure, but omega-3 fatty acid supplementation didn’t have any effect on cardiac biomarkers measured in a small, single-center, prospective study.
“One year of HIIT training reduces adiposity but had no consistent effect on myocardial triglyceride content or visceral adiposity,” wrote lead author Christopher M. Hearon Jr., PhD, and colleagues in JACC: Heart Failure. “However, long-duration HIIT improves fitness and induces favorable cardiac remodeling.” Omega-3 supplementation, however, had “no independent or additive effect.” Dr. Hearon is an instructor of applied clinical research at University of Texas Southwestern Medical Center in Dallas.
Dr. Christopher M. Hearon
Investigators there and at the Institute for Exercise and Environmental Medicine at Texas Health Presbyterian Hospital Dallas studied 80 patients aged 40-55 years classified as high risk for HF and obese, randomizing them to a year of high-intensity interval training (HIIT) with supplementation of either 1.6 g omega-3 FA or placebo daily; or to a control group split between supplementation or placebo. Fifty-six patients completed the 1-year study, with a compliance rate of 90% in the HIIT group and 92% in those assigned omega-3 FA supplementation.
Carl J. “Chip” Lavie, MD, of the John Ochsner Heart and Vascular Institute in New Orleans, commented that, although the study was “extremely well done from an excellent research group,” it was limited by its small population and relatively short follow-up. Future research should evaluate HIIT and moderate exercise on clinical events over a longer term as well as different doses of omega-3 “There is tremendous potential for omega-3 in heart failure prevention and treatment.”
HIIT boosts exercise capacity, more
In the study, the HIIT group showed improvement in a number of cardiac markers: around a 22% improvement in exercise capacity as measured by absolute peak and relative peak oxygen uptake (VO2), even without significant weight loss. They improved an average of 0.43 L/min (0.32-0.53; P < .0001) and 4.46 mL/kg per minute (3.18-5.56; P < .0001), respectively.
The researchers attributed the increase in peak VO2 to an increase in peak cardiac output averaging 2.15 L/min (95% confidence interval, 0.90-3.39; P = .001) and stroke volume averaging 9.46 mL (95% CI, 0.65-18.27; P = .04). A year of exercise training also resulted in changes in cardiac remodeling, including increases in left ventricle mass and LV end diastolic volume, averaging 9.4 g (95% CI, 4.36-14.44; P < .001) and 12.33 mL (95% CI, 5.61-19.05; P < .001), respectively.
The study also found that neither intervention had any appreciable impact on body weight, body mass index, body surface area or lean mass, or markers of arterial or local carotid stiffness. The exercise group had a modest decrease in fat mass, averaging 2.63 kg (95% CI,–4.81 to –0.46; P = .02), but without any effect from omega-3 supplementation.
The study acknowledged that high-dose omega-3 supplements have been found to lower triglyceride levels in people with severe hypertriglyceridemia, and hypothesized that HIIT alone or with omega-3 supplementation would improve fitness and biomarkers in people with stage A HF. “Contrary to our hypothesis, we found that one year of n-3FA [omega-3 FA] supplementation had no detectable effect on any parameter related to cardiopulmonary fitness, cardiovascular remodeling/stiffness, visceral adiposity, or myocardial triglyceride content,” Dr. Hearon and colleagues wrote.
Dr. Carl J. Lavie
The study “shows that obese middle-aged patients with heart failure with preserved ejection fraction [HFpEF] can markedly improve their fitness with HIIT and, generally, fitness is one of the strongest if not the strongest predictor of prognosis and survival,” said Dr. Lavie.
“Studies are needed on exercise that improves fitness in both HF with reduced ejection fraction and HFpEF, but especially HFpEF,” he said.
The study received funding from the American Heart Association Strategically Focused Research Network. Dr. Hearon and coauthors have no relevant disclosures. Dr. Lavie is a speaker and consultant for PAI Health, the Global Organization for EPA and DHA Omega-3s and DSM Nutritional Products.