One-year aerobic interval training in outpatients with schizophrenia: A randomized controlled trial

Although aerobic interval training (AIT) is recognized to attenuate the risk of cardiovascular disease (CVD) and premature mortality, it appears that it rarely arrives at patients' doorsteps. Thus, this study investigated 1-year effects and feasibility of AIT delivered with adherence support in collaborative care of outpatients with schizophrenia. Forty-eight outpatients (28 men, 35 [31-38] (mean [95% confidence intervals]) years; 20 women, 36 [30-41] years) with schizophrenia spectrum disorders (ICD-10) were randomized to either a collaborative care group provided with municipal transportation service and training supervision (walking/running 4 × 4 minutes at ~90% of peak heart rate; HR_peak ) 2 d wk^-1 at the clinic (TG) or a control group (CG) given 2 introductory AIT sessions and advised to continue training. Directly assessed peak oxygen uptake ( ${\dot{V}O}_{2\text{peak}}$ ) increased in the TG after 3 months (2.3 [0.6-4.4] mL kg^-1 min^-1 , Cohen's d = 0.33[-4.63 to 4.30], P = 0.04), 6 months (2.7 [0.5-4.8] mL kg^-1 min^-1 , Cohen's d = 0.42[-4.73 to 4.11], P = 0.02) and 1 year (4.6 [2.3-6.8] mL kg^-1 min^-1 , Cohen's d = 0.70[-4.31 to 4.10], P < 0.001) compared to the CG. One-year cardiac effects revealed higher HR_peak (7 [2-11] b min^-1 , Cohen's d = 0.34[-8.48 to 8.65], P = 0.01), while peak stroke volume tended to be higher (0.9 [-0.2 to 2.0] mL b^-1 , Cohen's d = 0.35[-1.62 to 2.01], P = 0.11) in the TG compared to the CG. Conventional risk factors (body weight, waist circumference, blood pressure, and lipids/glucose) remained unaltered in both groups. One-year AIT adherence rates were 15/25 (TG; different from CG: P < 0.001) and 0/23 (CG). AIT was successfully included in long-term collaborative care of outpatients with schizophrenia and yielded improved ${\dot{V}O}_{2\text{peak}}$ , advocating this model for aerobic capacity improvement and CVD risk reduction in future treatment.