Improved metabolic fitness, but no cardiovascular health effects, of a low-frequency short-term combined exercise programme in 50-70-year-olds with low fitness: A randomized controlled trial

Abstract

We evaluated the cardiometabolic effects of a 15-week combined exercise programme, implemented in sports clubs, for 50-70-year-olds with low aerobic fitness. In a randomized controlled trial, 45 participants (26 women) with low fitness were randomly assigned (2:1-ratio) to a training group (TG, n = 30) or inactive control group (CG, n = 15). TG had 15 weeks with one weekly 90-min supervised group-based session in a recreational sports club with combined aerobic exercise and strength training and were encouraged to perform home-based training 30 min/wk. Evaluations of relative VO_2max (mLO₂/min/kg), blood pressure, resting heart rate (HR), echocardiography, peripheral arterial tonometry, body composition, lipid profile and HbA1c were performed at 0 and 15 wks. Average HR during supervised training was 113 ± 13 bpm (68.6 ± 7.0%HR_max), with 4.3 ± 6.6% spent >90%HR_max. At 15-wk follow-up, intention-to-treat analyses revealed no between-group difference for VO_2max/kg (0.4 mLO₂/min/kg, 95%CI -0.8-1.5, P = 0.519; -3 mL/min, 95%CI -123-118, P = 0.966) or other cardiovascular outcomes (all P > 0.05). Compared to CG, total fat mass (-1.9 kg; 95%CI -3.2 to -0.5, P = 0.005), total fat percentage (-1.3%, 95%CI -2.2 to -0.3, P = 0.01) and total/HDL cholesterol ratio (P = 0.032) decreased in TG. Regular adherence to supervised training was high (81%), but 0% for home-based exercise. In conclusion, the group-based supervised training was associated with high adherence and moderate exercise intensity, whereas insufficiently supported home-based training was not feasible. Together, 15 wks of combined exercise training did not improve aerobic fitness or affected cardiovascular function in 50-70-yr-olds with low aerobic fitness, whereas some positive effects were observed in metabolic parameters.Highlights Combined exercise training implemented in a sports club elicited moderate aerobic intensity in 50-70-year-old untrained individuals.Supervised group-based training had high adherence whereas unsupported home-based training had very low adherence.15 weeks of low-frequency combined moderate intensity exercise training improved lipid profile and fat mass, but had no effect on cardiovascular fitness.

Keywords: Aerobic fitness; adherence; body composition; exercise intensity; fat percentage.