The Effects Of Exercise Intensity And Obesity On Sleep Duration And Quality

Exercise is recommended to improve sleep, but the role of exercise intensity is unclear. In addition, whether obesity interacts with exercise intensity to affect sleep is unknown. PURPOSE: To investigate the effects of exercise intensity and obesity on parameters related to sleep quality (sleep efficiency [SE], sleep onset latency [SOL], wake after sleep onset [WASO], and awakenings). METHODS: Six adults with obesity (OB; 2 M/4F; age: 35.7 ± 9.7 y; BMI: 34.4 ± 2.9; VO2peak: 21.4 ± 3.2 mL/kg/min) and seven normal weight adults (NW; 4 M/3F; age: 33.4 ± 14.5 y; BMI: 22.9 ± 1.9 kg/m2; VO2peak: 32.4 ± 5.6 mL/kg/min) completed a maximal graded cardiopulmonary peak oxygen uptake (VO2peak)/lactate threshold (LT) test on a cycle ergometer to determine exercise intensity for 3 randomized control or calorically matched exercise bouts: a) CON, no exercise; b) MOD, the power output (PO) at LT; c) HIGH, the PO associated with 75% of the difference between LT and VO2peak. Each visit occurred in the morning between 08:00-09:00 h. Sleep variables were recorded with Philips Respironics Actiwatch Spectrum Plus monitors. Participants wore the watch the day before each testing visit and through the night after the testing visit. The Cole-Kripke algorithm was used to score the actigraphy data. 2x3 mixed model ANOVAs were utilized to assess the effect of obesity status and exercise intensity on each sleep parameter using delta scores of the night before and night after each condition. Data are reported as mean ± SD. RESULTS: NW slept an average of 7.8 ± 1.35 hrs, and OB slept an average of 7.15 ± 1.4 hrs; sleep duration was not significantly different in any group or condition (p = 0.51-0.99). Compared with CON, MOD was associated with a lower SE (-2.8 ± 5.3% vs + 3.4 ± 6.2%, p < 0.01) and higher SOL (+5.1 ± 12.2 vs -9.3 ± 20.4 minutes, p < 0.05). Sleep parameters were not different between HIGH and CON or HIGH and MOD (all;p > 0.05). Regardless of condition, SE was higher in the OB group compared with NW (+2.6 ± 6% vs -1.4 ± 5.1 %, p = 0.01). CONCLUSION: SE and SOL may be affected by moderate intensity exercise. In addition, obesity status may impact the quality of sleep. Supported by: UVA School of Education and Human Development and NIH NIDDK (R01 DK129510)