Does Sleep Restriction Impact Subsequent Day Free-living Physical Behavior Patterns Among Healthy Young Adults?

Sleep restriction may alter physical behaviors, such as physical activity and sedentary time. PURPOSE: To determine the impact of a single night of early awakening sleep restriction on subsequent physical behaviors, compared with a full night of sleep in healthy young adults. METHODS: Twenty-one (62%F, 20.2 ± 2.0 yrs) healthy young adults participated in a free-living, randomized counter-balanced study in which they were assigned a night of sleep restriction (SR, 3 hrs sleep) and a night of full sleep (FULL, 8 hrs sleep) during a 14-day period. Participants wore an ActiGraph GT9X accelerometer on the non-dominant wrist. The Hildebrand 2014 method was used to identify sedentary behavior (SED), light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA). Sleep logs were used to isolate waking hours. Average bout durations were calculated for SED bouts (≥ 30 min), as well as LPA and MVPA bouts (≥10 min). Linear mixed effects regression models were used to examine the effect of sleep condition (SR vs FULL) on 1) average time spent in SED, LPA and MVPA per day and 2) average SED, LPA, and MVPA bout duration. Total awake time was included as a covariate in daily average models to account for additional wake time on the day following SR. RESULTS: Time spent in SED was higher on days 1 and 3 post-SR, compared with days 1 and 3 post-FULL (p < 0.05). Conversely, there was no significant effect of SR on time spent in LPA or MVPA, nor average bout duration, compared with FULL (p > 0.05, Table 1). No other interactions were significant. CONCLUSION: Sedentary time was increased on days 1 and 3 post-SR, compared with FULL. Alternative physical behavior metrics or data analysis methods (e.g., iso-temporal substitution) may be warranted to better understand the relationship between SR and subsequent physical behaviors. - Days Post-FULL Condition Days Post-SR Condition 1 2 3 1 2 3 Total Wear Time (min) 950.35(88.32) 924.33(117.96) 960.16(138.59) 1223.95(114) 954.86(112.91) 985.2(141.04) SED (min) 704.59(123.87) 700.19(108.99) 646.68(138.66) 960.24(120.41) 697.62(153.38) 716.05(119.95) SED (bout duration) 74.18(61.28)(n = 96) 77.37(62.79)(n = 109) 78.69(75.79)(n = 89) 78.48(67.51)(n = 164) 81(93.69)(n = 107) 80.83(93.59)(n = 109) LPA (min) 141.65(61.45) 141.95(72.42) 192.16(86.23) 165.05(67.2) 155.86(74.38) 165.74(78.57) LPA (bout duration) 13.33(4.16)(n = 3) 11.92(3.48)(n = 13) 11.22(0.97)(n = 9) 15.42(10.77)(n = 12) 11(1)(n = 3) 14.29(4.23)(n = 7) MVPA (min) 91.69(52.89) 82.19(40.96) 103.29(67.03) 98.67(60.43) 93.5(50.07) 90.9(50.11) MVPA (bout duration) 18.5(11.25)(n = 26) 15.18(8.94)(n = 28) 17.39(9.54)(n = 23) 16.45(8.39)(n = 40) 16.36(7.94)(n = 36) 15.05(5.37)(n = 22) University of Massachusetts Amherst Graduate School Dissertation Grant