Exercise tolerance is reduced in bipolar illness

BackgroundCardiovascular and cerebrovascular disease is 2–3 times more common in bipolar patients than the general population. Asymptomatic bipolar patients have electrocardiogram abnormalities at high rates. The question of heart function in asymptomatic bipolar subjects arises.MethodsThis study examined the impact of exhaustive exercise on cardiac function in untrained euthymic bipolar and control subjects. Twenty-four non-athletic adults, 10 controls and 14 with bipolar type I, exercised on a treadmill at 70% of maximal oxygen consumption until physical exhaustion. Two-dimensional and Doppler echocardiography were performed before and immediately after exercise.ResultsBipolar subjects had significantly reduced exercise duration (75.9 ± 40.5min for bipolar and 95.0 ± 40.1 min for control, P < 0.01). There were no statistical differences between bipolar illness and normal controls in echocardiographic variables either at rest or after exhaustive exercise.ConclusionMedically asymptomatic, euthymic bipolar subjects appear to have reduced exercise tolerance but normal cardiac function.LimitationsMore bipolar patients smoked (28.6% vs. 0% controls) and patients tended to be heavier (189.1 ± 29.3 vs. 165.0 ± 29.5 lb, t = 2.0, P = 0.06). None of the normal controls were taking any medications. These variables could have impacted the reduced exercise tolerance.