Aerobic Interval Training Versus Continuous Moderate Exercise as a Treatment for the Metabolic Syndrome

TLDR

Metabolic syndrome triples the risk of heart disease death, and while exercise mitigates its symptoms, the optimal intensity remains debated. The study aimed to compare the effects of moderate continuous exercise versus high‑intensity aerobic interval training on cardiovascular function and prognosis in metabolic syndrome patients. Thirty‑two patients were randomized to 16 weeks of equal‑volume moderate continuous exercise (70 % HRmax) or aerobic interval training (90 % HRmax) performed three times weekly. Aerobic interval training produced greater improvements than moderate continuous exercise in VO₂max, endothelial function, insulin signaling, muscle biogenesis, and metabolic risk factors, while both modalities similarly lowered blood pressure and weight, underscoring intensity as key for reversing metabolic syndrome risk.

Abstract

Individuals with the metabolic syndrome are 3 times more likely to die of heart disease than healthy counterparts. Exercise training reduces several of the symptoms of the syndrome, but the exercise intensity that yields the maximal beneficial adaptations is in dispute. We compared moderate and high exercise intensity with regard to variables associated with cardiovascular function and prognosis in patients with the metabolic syndrome.Thirty-two metabolic syndrome patients (age, 52.3+/-3.7 years; maximal oxygen uptake [o(2)max], 34 mL x kg(-1) x min(-1)) were randomized to equal volumes of either moderate continuous moderate exercise (CME; 70% of highest measured heart rate [Hfmax]) or aerobic interval training (AIT; 90% of Hfmax) 3 times a week for 16 weeks or to a control group. o(2)max increased more after AIT than CME (35% versus 16%; P<0.01) and was associated with removal of more risk factors that constitute the metabolic syndrome (number of factors: AIT, 5.9 before versus 4.0 after; P<0.01; CME, 5.7 before versus 5.0 after; group difference, P<0.05). AIT was superior to CME in enhancing endothelial function (9% versus 5%; P<0.001), insulin signaling in fat and skeletal muscle, skeletal muscle biogenesis, and excitation-contraction coupling and in reducing blood glucose and lipogenesis in adipose tissue. The 2 exercise programs were equally effective at lowering mean arterial blood pressure and reducing body weight (-2.3 and -3.6 kg in AIT and CME, respectively) and fat.Exercise intensity was an important factor for improving aerobic capacity and reversing the risk factors of the metabolic syndrome. These findings may have important implications for exercise training in rehabilitation programs and future studies.