Twelve weeks of water-based circuit training exercise improves fitness, body fat and leg strength in people with stable coronary heart disease: a randomised trial

Question: In people with stable coronary heart disease, what are the effects of water-based circuit training exercise on aerobic capacity, strength and body composition? How do these effects compare with those of gym-based exercise? Design: Parallel group, randomised controlled trial with concealed allocation and intention-to-treat analysis. Participants: Fifty-two participants with stable coronary heart disease. Interventions: Twelve weeks of: three 1-hour sessions per week of moderate-intensity water-based circuit training exercise with alternating aerobic and resistance stations (WEX); three 1-hour sessions per week of moderate-intensity gym-based circuit training exercise (GEX); or continuing usual activities (control). Outcome measures: Aerobic capacity (VO_2peak), upper and lower limb one repetition maximum strength (biceps curl, latissimus dorsi pulldown, hamstring curl and leg press), anthropometry (weight, body mass index and girth) and dual energy x-ray absorptiometry. Results: Forty-five participants completed the study (WEX n = 15, GEX n = 18, control n = 12). Both training groups significantly improved VO_2peak compared with control: WEX by 2.5 ml/kg/min (95% CI 0.6 to 4.4) and GEX by 2.3 ml/kg/min (95% CI 0.6 to 4.0). WEX and GEX improved hamstring strength compared with control: WEX by 6.3 kg (95% CI 1.2 to 11.3) and GEX by 7.6 kg (95% CI 2.9 to 12.2). Compared with control, GEX increased leg press strength by 15.5 kg (95% CI 5.7 to 25.3), whereas the effect of WEX was less clear (MD 7.1 kg, 95% CI –3.5 to 17.7). Only GEX improved latissimus dorsi pulldown strength. Compared with control, total body fat was reduced with WEX (–1.1 kg, 95% CI –2.3 to 0.0) and GEX (–1.2 kg, 95% CI –2.3 to –0.1). There were negligible between-group differences in weight or waist circumference. Conclusion: WEX was well tolerated and improved aerobic capacity, leg strength and body fat to a similar degree as GEX in people with coronary heart disease. These findings suggest that WEX is an effective exercise training alternative to GEX for people with coronary heart disease. Trial registration: ANZCTR12616000102471.