Background: Increased mortality in schizophrenia is caused largely by coronary heart disease (CHD). Low cardiorespiratory fitness (CRF) is a key factor for CHD mortality. We compared CRF in patients with schizophrenia to CRF of matched healthy controls and reference values. Also, we examined the effects of exercise therapy on CRF in patients with schizophrenia and in controls.
Methods: Sixty-three patients with schizophrenia and 55 controls, matched for gender, age, and socioeconomic status, were randomized to exercise (n = 31) or occupational therapy (n = 32) and controls to exercise (n = 27) or life as usual (n = 28). CRF was assessed with an incremental cardiopulmonary exercise test and defined as the highest relative oxygen uptake (V˙O2peak) and peak work rate (Wpeak). Minimal compliance was 50% of sessions (n = 52).
Results: Male and female patients with schizophrenia had a relative V˙O2peak of 34.3 ± 9.9 and 24.0 ± 4.5 mL·kg−1·min−1, respectively. Patients had higher resting HR (P < 0.01) and lower peak HR (P < 0.001), peak systolic blood pressure (P = 0.02), relative V˙O2peak (P < 0.01), Wpeak (P < 0.001), RER (P < 0.001), minute ventilation (P = 0.02), and HR recovery (P < 0.001) than controls. Relative V˙O2peak was 90.5% ± 19.7% (P < 0.01) of predicted relative V˙O2peak in male and 95.9% ± 14.9% (P = 0.18) in female patients. In patients, exercise therapy increased relative V˙O2peak compared with decreased relative V˙O2peak after occupational therapy. In controls, relative V˙O2peak increased after exercise therapy and to a lesser extent after life as usual (group, P < 0.01; randomization, P = 0.03). Exercise therapy increased Wpeak in patients and controls compared with decreased Wpeak in nonexercising patients and controls (P < 0.001).
Conclusion: Patients had lower CRF levels compared with controls and reference values. Exercise therapy increased V˙O2peak and Wpeak in patients and controls. V˙O2peak and Wpeak decreased in nonexercising patients.