Aerobic exercise improves gastrointestinal motility in psychiatric inpatients.

Aim: To evaluate the benefit of aerobic exercise on colonic transit time (CTT) for psychiatric inpatients in a closed ward.

Methods: Sixty consecutive adult inpatients of the Somang Hospital Psychiatry Unit (Eumsung-gun, South Korea), without CTT-related diseases or drug therapies, were recruited for study from March to June of 2012. Upon enrollment, the patients were randomly assigned to partake in a 12-wk instructor-led group aerobic exercise program (exercise group; n = 30) or to maintain their ordinary daily activities (control group; n = 30). The exercise program was structured as 10 min warm-up (stretching), 40 min exercise, and 10 min cool-down (stretching) for three days each week. The exercise sessions consisted of walking only in week one and aerobics from weeks two to 12, with increasing intensity (50% heart rate reserve (HRR) for weeks one to four, 60% HRR for weeks five to eight, and 70% HRR for weeks nine to 12). CTT was measured before (baseline) and after (week 12) the exercise program, in duplicate (on days four and seven), using abdominal radiography and the multiple radio-opaque marker technique. Changes in the exercising patients' CTT and weight-, cardiovascular- and fitness-related parameters were statistically assessed.

Results: The study dropout rate was 30.0%, with 23 patients in the exercise group and 19 patients in the control group completing the study. At week 12, the exercise group showed decreases in body weight (mean ± SE) baseline: 69.4 ± 2.8 vs study-end: 67.6 ± 2.7; P < 0.635) and body mass index (BMI) (25.2 ± 1.1 vs 24.9 ± 0.8; P < 0.810), but the extent of change was not significantly different from that experienced by the control group (body weight: 68.8 ± 4.0 vs 68.8 ± 3.9; BMI: 24.3 ± 1.1 vs 24.4 ± 1.2). However, the exercise group showed significant improvements in leg muscle strength (baseline: 41.7 ± 4.3 vs study-end: 64.1 ± 5.0; P < 0.001), cardio-respiratory endurance (120.5 ± 4.5 vs 105.4 ± 2.8; P < 0.004), and leg muscle elasticity and power output (21.5 ± 2.6 vs 30.6 ± 2.8; P < 0.001). The exercise group showed an exercise-induced reduction in total CTT (baseline: 54.2 ± 8.0 vs 30.3 ± 6.1), which was significantly different from that experienced by the control group over the 12-wk period (48.6 ± 9.3 vs 48.3 ± 12.3; P = 0.027); however, the exercise-induced decreases in CTT involving the three colonic segments examined (right, left and recto-sigmoid) showed no significant differences from the control group.

Conclusion: A 12-wk aerobic exercise program can benefit psychiatric inpatients by increasing intestinal motility, possibly decreasing risk of metabolic- and cardiovascular-related disease.