Sleep Extension Favorably Affects Gait Speed, But Not Motor Dual Tasking In Young Adults

People are put in situations that require them to multitask every day. Walking and talking, listening to music and exercising, or watching TV and folding laundry are all examples of motor dual tasking. Sleep affects multiple cognitive and motor processes, and a lack of sleep could have deleterious effects on motor dual tasking performance but the influence of sleep extension on multitasking is unclear. PURPOSE: To investigate the effects of sleep extension on dual tasking and gait speed in young adults. METHODS: Twenty-eight young adults who self-reported sleeping <7 hours/night (11 M/17F, age = 23 ± 2) were instructed to sleep one extra hour per night for two weeks. The Pittsburgh Sleep Quality Index (PSQI) was used to derive sleep duration (in hours) and global score (0-21; higher is worse). Participants performed a 7-meter instrumented stand and walk (iSAW) test during a verbal fluency task to create a dual-tasking environment. Gait speed was measured during single-task and dual-task conditions before and after one hour of sleep extension. Motor dual task effect (mDTE) was calculated with the following equation: (DT-ST)/ST. Paired samples t-tests were used to compare mDTE performance and gait speed before and after sleep extension. RESULTS: Participants reported sleeping longer (6.2 ± 0.9 vs. 7.3 ± 1.0 hours, p < .001) and reported improved PSQI scores (5.4 ± 1.6 vs. 3.4 ± 1.4, p < .001) after the sleep extension intervention. Participants walked slower during dual-tasking compared with single-tasking (0.944 ± 0.165 vs 1.13 ± 0.144 m/s, p < .001), demonstrating the verbal fluency tasks were challenging for participants. Participant gait speed was faster for both single-task (1.091 ± 0.133 vs 1.177 ± 0.156 m/s), and dual-task conditions (0.928 ± 0.150 vs. 0.960 ± 0.181 m/s) after sleep extension (p < .001). CONCLUSION: Gait speed increases with sleep extension, indicating a possible positive benefit on single-task gait function, but does not influence cognitive load and resource allocation in our sample. Future directions include examining both the relations between gait speed and sleep extension, as well as how walking impacts cognitive performance through analysis of response accuracy and quantity during verbal fluency tasks.