Dual Tasking Using a Treadmill Desk Affects Middle-Aged but Not Young Adults

Abstract

PURPOSE: Young adults have the capacity to manage dual task conditions with minimal impairment to either the cognitive or the motor task; however, this ability decreases with age. Previous research on dual tasking has primarily examined over ground walking and minimal information is available on dual tasking on a treadmill. The purpose of this study was to examine the effect of dual tasking using a treadmill desk on changes in cognitive performance and gait parameters in young adults (YA) and middle-aged adults (MA). METHODS: YA (n=24; mean age 21.1±1.6 yrs) and MA (n=25; mean age 53.0±5.3 yrs) were recruited to participate in this study. Participants completed five cognitive tests (Stroop Word Color Test, phoneme monitoring, typing test, Sternberg working memory test, and serial 7 subtractions) in a single task (ST) and dual task (DT) condition in a randomized and counterbalanced order. Participants were seated at a desk for ST and walked on a treadmill desk at self-selected speed (mean speed YA=1.5±0.4 mph; MA=1.4±0.5 mph) during DT. An OptoGait system recorded gait parameters of step length, stride length, and coefficient of variation. RESULTS: There were no significant differences in gait parameters or test scores in YA when comparing DT and ST conditions (p>0.05). MA performed worse on word recall score (89.7±11.3 vs 96.6±7.5%, p=0.03), typing speed (44.9±11.2 vs 49.9±13.3 wpm, p=0.00), and Sternberg reaction time (1.5±2.0 vs 1.0±1.9 s, p=0.00) during the DT compared to the ST condition. MA stride length decreased during DT in the Sternberg test (37.7±5.9 vs 36.5±5.3 in, p=0.01) and serial 7 subtractions (37.2±5.7 vs 36.5±5.3 in, p=0.00). MA showed detriments in reaction times on the Stroop test (0.8±1.2 vs 0.6±0.9 s, p=0.00) and Sternberg test (1.5±2.0 vs 0.9±1.5 s, p=0.02) and decreased word recall score (89.7±11.3 vs 97.5±7.0%, p=0.04) compared to YA during the DT condition. CONCLUSION: The impairments in gait and cognitive test scores in MA but not YA suggest that the ability to simultaneously process cognitive demands and treadmill walking requirements decreases with age. Using a treadmill desk might affect work-related performance or gait parameters in middle-aged adults.