Does Time of Day influence postural control and gait? A review of the literature

Background: Like many physiologic processes, Time of Day may influence postural control and gait. A better understanding of diurnal variations in postural control and gait may help to improve diagnoses, reduce falls, and optimize rehabilitation and training routines. This review summarizes the current literature that addresses these questions. Research Question: Does time of day affect postural control and gait? Methods: We searched PubMed, Google Scholar, and IEEE using a combination of keyword and MeSH terms. We included papers that studied human subjects and assessed gait or postural control as a function of time of day. We evaluated the quality of the identified papers based on nine assessment criteria and analyzed them considering the topic (postural control or gait), age, and characteristics of the conducted assessments. We then quantitatively synthesized the results across studies using a meta-analytical approach (i.e., Hedges' g model). Results: Twenty-two papers considered the relationship between time of day and postural control, and eleven considered the relationship between time of day and gait. Six studies found that postural control was best in the morning, four described postural control being best in the afternoon, four described optimal postural control in the evening, and eight reported no time of day effect. Two studies found gait best in the morning, five described gait best in the afternoon, two described optimal gait in the evening, and two reported no time of day effect. The results of the quantitative analysis suggest that both postural control and gait were best in the evening. Significance: While there is no clear consensus on whether there is a time of day effect for postural control and gait, the findings of this review provide initial evidence suggesting that a small but statistically significant effect exists in favor of the evening. Standardized testing, including repeated and continuous evaluations, may help provide more definitive information on time of day influences on postural control and gait.