The functional exercise capacity in patients with bipolar disorder versus healthy controls: A pilot study Davy Vancampfort a,b,n , Sabine Wyckaert b , Pascal Sienaert b , Marc De Hert a,b , Brendon Stubbs c , Roselien Buys a , Ans Schueremans b , Michel Probst a,b a KU Leuven – University of Leuven Department of Rehabilitation Sciences, Tervuursevest 101, 3001 Leuven, Belgium b UPC KU Leuven, Campus Kortenberg, KU Leuven – University of Leuven Department of Neurosciences, Leuvensesteenweg 517, 3070 Kortenberg, Belgium c School of Health and Social Care, University of Greenwich, Southwood Site Avery Hill Road, Eltham, London SE9 2UG, UK article info Article history: Received 8 September 2014 Received in revised form 17 June 2015 Accepted 12 July 2015 Available online 16 July 2015 Keywords: Exercise Physical activity Physical Fitness Bipolar Disorder abstract The aim of the current study was to compare the functional exercise capacity of patients with bipolar disorder with age-, gender- and body mass index (BMI)-matched healthy controls. Thirty patients (16 ♂, 40.8 711.6 years) and healthy controls (16 ♂, 40.5 710.8 years) were included. All participants per- formed a 6-min walk test to assess the functional exercise capacity and completed the International Physical Activity Questionnaire. Patients were screened for psychiatric symptoms using the Quick In- ventory of Depressive Symptomatology and Hypomania Checklist-32. Results demonstrated that patients with bipolar disorder demonstrated a significantly poorer functional exercise capacity (590.8 7112.6 versus 704.2 794.3 m). A backward stepwise regression analyses showed that the level of depression and existing foot or ankle static problems and back pain before the test explained 70.9% of the variance in the distance achieved on the 6-min walk test (functional exercise capacity). The current study demon- strates that foot and back pain appear to be important negative predictors of functional exercise capacity in patients with bipolar disorder. Physical activity interventions delivered by physical therapists may help ameliorate pain symptoms and improve functional exercise capacity. & 2015 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Next to a higher risk for cardiovascular diseases (CVD) (Prieto et al., 2014) and associated increased mortality rates (Fiedorowicz et al., 2014), patients with bipolar disorder are more likely to ex- perience an impaired quality of life (IsHak et al., 2012). Relative to the extensive literature now available on many aspects of CVD in bipolar disorder (Swartz and Fagiolini, 2012; Smith et al., 2013; Vancampfort et al., 2013a), there is limited evidence available concerning the influence of increased medical co-morbidities on the functional limitations in daily living in patients with bipolar disorder. In recognition of this, recently a call (Stubbs et al., 2014) was made to consider also the functional outcomes associated with medical co-morbidities in the treatment of bipolar disorder. Walking, a common activity of daily living, is a convenient functional exercise which might improve mental and physical functioning in patients with bipolar disorder (Ng et al., 2007; Van Citters et al., 2010). Timed walk tests such as the 6 min walk test (6 MWT) might therefore be ideal to evaluate the functional ex- ercise capacity. The 6 MWT has been used successfully to observe the functional exercise capacity in other mental health popula- tions (Vancampfort et al., 2011a, 2013b; Bernard et al., 2014). The 6 MWT is a safe and easy to administer physical fitness test which evaluates the global and integrated responses of the cardiovas- cular, peripheral circulation and neuromuscular systems involved during walking (American Thoracic Society, 2002). Although the 6 MWT does not provide specific information on the function of each of the different systems involved in walking or the me- chanisms of walking limitations, it assesses the sub-maximal level of the exercise capacity (American Thoracic Society, 2002). Be- cause most activities of daily living are performed at sub-maximal levels of exertion, the test reflects well the functional level for performing daily life physical activities (Bernard et al., 2014) while it is related to lower quality of life (Martín-Sierra et al., 2011). To date, the functional exercise capacity of patients with bi- polar disorder has not been compared with a healthy control group. Also, little is known about which mental and physical fac- tors may influence the functional exercise capacity in patients with bipolar disorder. It might be reasonable to assume that a lower level of physical activity participation (Janney et al., 2014), higher rates of cigarette smoking (Waxmonsky et al., 2005), manic Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/psychres Psychiatry Research http://dx.doi.org/10.1016/j.psychres.2015.07.040 0165-1781/& 2015 Elsevier Ireland Ltd. All rights reserved. n Corresponding author at: KU Leuven – University of Leuven Department of Rehabilitation Sciences, Tervuursevest 101, 3001 Leuven, Belgium. Fax: þ32 2 759 9879. E-mail address: Davy.Vancampfort@uc-kortenberg.be (D. Vancampfort). Psychiatry Research 229 (2015) 194–199