Sleep restriction decreases the physical activity of adults at risk for type 2 diabetes

Abstract

Study objective: To test the hypothesis that recurrent sleep curtailment will result in decreased physical activity in adults at risk for type 2 diabetes.

Design: Two-condition 2-period randomized crossover study.

Setting: University General Clinical Research Center.

Participants: Eighteen healthy patients with parental history of type 2 diabetes (9 females and 9 males, age 27 yr [standard deviation 3], body mass index 23.7 [2.3] kg/m²).

Interventions: Two week-long inpatient sessions with 8.5 or 5.5-hr nighttime sleep opportunity. Participants who exercised regularly (39%) could follow their usual exercise routines during both sessions.

Measurements and results: Sleep and total body movement were measured by wrist actigraphy and waist accelerometry. Subjective mood and vigor was assessed using visual analog scales. The main outcome was the comparison of total activity counts between sleep conditions. Ancillary endpoints included changes in sedentary, light, and moderate plus vigorous activity, and their association with changes in mood and vigor. Daily sleep was reduced by 2.3 hr (P < 0.001) and total activity counts were 31% lower (P = 0.020) during the 5.5-hr time-in-bed condition. This was accompanied by a 24% reduction in moderate-plus-vigorous activity time (P = 0.005) and more sedentary behavior (+21 min/day; P = 0.020). The decrease in daily activity during the 5.5-hr time-in-bed condition was seen mostly in participants who exercised regularly (-39 versus -4% in exercisers versus nonexercisers; P = 0.027). Sleep loss-related declines in physical activity correlated strongly with declines in subjective vigor (R = 0.90; P < 0.001).

Conclusions: Experimental sleep restriction results in decreased amount and intensity of physical activity in adults at risk for type 2 diabetes.

Keywords: Physical activity; familial risk of diabetes; regular exercise; sedentary behavior; sleep restriction.

Figure 1

(A) Mean (+standard error, SE) total activity counts during the 8.5-h (open bar) and 5.5-h time-in-bed (shaded bar) experimental condition. *P = 0.020 for the effect of time in bed using repeated-measures analysis of variance with exercise category as a between-subject factor. (B) Mean (+SE) total activity counts during each sleep condition in the regular exercise (open circles) and no exercise (solid triangles) group of participants. *In addition to the main effect of time-in-bed condition (P = 0.020), there was a main effect of exercise versus no exercise category (P = 0.012) and a significant interaction between exercise category and time-in-bed condition (P = 0.027).

Figure 2

(A) Estimated mean (± standard error, SE) change in daily time allocation to sedentary, light, and moderate plus vigorous physical activity during the 5.5-hr compared with the 8.5-hr time-in-bed condition, based on repeated-measures analysis of variance with exercise category as a between-subject factor. (B) Mean (+ SE) daily time spent sedentary during each sleep condition in the regular exercise (open circles) and no exercise (solid triangles) group of participants. (C) Mean (+ SE) daily time allocated to moderate plus vigorous physical activity during each sleep condition in the regular exercise (open circles) and no exercise (solid triangles) group of participants. (D) Mean (± SE) daily time allocated to light-intensity physical activity during each sleep condition in the regular exercise (open circles) and no exercise (solid triangles) group of participants. Repeated-measures analysis of variance was used to derive reported P values for the effect of time-in-bed (TIB) condition as a within-subject factor, exercise category (EC) as a between-subject factor, and their interaction (TIB × EC).