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

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.