6-minute Walk Test Offers Insight Into Global Functioning Among Patients With Bipolar Disorder
Until now, assessment of aerobic exercise capacity included expensive and time-consuming laboratory tests that do not necessarily accurately reflect patients’ day-to-day physical functioning.
Global functioning in patients with bipolar disorder is significantly associated with patients' function exercise capacity as assessed by the 6-minute walk test, investigators reported in a recently published study.
“When one considers that functional exercise capacity is an essential requirement for all activities of daily living, the importance of promoting interventions targeting the functional exercise capacity in people with bipolar disorder is clearly clinically relevant,” the authors wrote. They also noted a link between depressive symptoms and reduced global functioning and functional exercise capacity, possibly due to lower self-efficacy.
Past research had already suggested a link between exercise capacity and overall functioning in patients with bipolar disorder. Although the gold standard for assessing aerobic exercise capacity includes gas analysis and maximum oxygen level consumption in laboratory tests, these procedures are expensive and time-consuming and do not necessarily accurately reflect patients' day-to-day physical functioning. The 6-minute walk test, however, overcomes those obstacles.
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Davy Vancampfort, PhD, of the University of Leuven in Belgium, and his colleagues assessed 65 individuals with bipolar disorder using several instruments: the 6-minute walk test, the Global Assessment of Functioning (GAF), the Inventory of Depressive Symptomatology Self Report (QIDS) and the International Physical Activity Questionnaire (IPAQ). The adults were all white and included 19 outpatients and 46 inpatients, with ages ranging from 19 to 64.
The adults walked an average 615.6 meters (an average 580 m among women and 660 m among men) and had an average score of 55 on the GAF, resulting in a statistically significant positive association between these two assessments, even after controlling for QIDS scores. Total physical activity level showed a positive association with both the GAF and walk test scores while longer illness duration, smoking more daily cigarettes and a greater level of depressive symptoms were all negatively associated with both scores. Dosage of antipsychotic medications also had a negative association with GAF scores.
Statistical analysis revealed that 72% of the variance of the GAF score was explained by a patient's duration of illness, QIDS score and status as an inpatient. Meanwhile, age, QIDS score and GAF score significantly predicted the walk test score, accounting for 74% of the score's variance. The findings indicate that the 6-minute walk test relates to patients' global functional health and can inform treatment.
“Given the established increased risk of cardiometabolic diseases and our observed results indicating a relationship between better functional exercise capacity and global functioning, the need for promoting physical activity targeting exercise capacity among people with bipolar disorder is growing,” Vancampfort's team wrote.
“The promotion of physical activity could also focus on important functional goals, such as walking to the local shops instead of taking the bus, which might also offer an opportunity to gain the benefits of an active lifestyle whilst also achieving functional tasks."
Vancampfort D, Sienaert P, Wyckaert S, et al. The functional exercise capacity is associated with global functioning in people with bipolar disorder. J Nerv Ment Dis. 2016;204(9):673-677.