Cardiorespiratory fitness in outpatients with bipolar disorder versus matched controls: An exploratory study

Patients with bipolar disorder (BD) are approximately twice as likely to die prematurely due cardiovascular diseases (CVD) than the general population. Cardiorespiratory fitness (CRF) is an important health outcome measure, predictive for CVD and premature mortality.

The aim of the current study was to compare the CRF of outpatients with BD versus age-, gender-, and body mass index (BMI)-matched healthy controls (HC). A secondary aim was to assess potential correlates of CRF.

All participants underwent a maximal incremental exercise test to measure the maximum oxygen uptake (VO2max, the golden standard assessment of cardiorespiratory fitness), wore a Body Sensewear Armband for 5 subsequent days to assess their physical activity behavior and completed the Positive-and-Negative-Affect-Schedule (PANAS).

Outpatients with BD (n=20; 47.8±7.6years) had a significantly lower VO2max compared with HC (n=20; 47.8±7.6years) (26.0±7.3 versus 30.4±6.5ml/min/kg, P=0.047). A higher VO2max was correlated with younger age, higher active energy expenditure, higher PANAS positive and lower PANAS negative affect scores and a lower antipsychotic medication dose.

The limited sample and cross-sectional design preclude definitive conclusions.

Compared with HC, outpatients with BD have reduced CRF levels of approximately 4.4ml/min/kg. In the general population such reductions are associated with a 20% increased premature mortality risk. Interventions targeting CRF in BD are required. Although more research is needed, clinicians should consider the utility of objective assessments of CRF for risk stratification in outpatient settings.