The Association of Sleep Loss and Balance Stability in Farmers

ABSTRACT: Sleep deprivation has been linked to injuries, illnesses, and reduced performance measures. Yet, it is unclear how sleep loss contributes to the high rates of injuries and falls in agriculture. In this study, the authors evaluated sleep loss and quantified its association with balance in five farmers, who wore an ActiWatch to record their sleeping patterns in six repeated weekly observation periods. Acute sleep loss was computed as the net sleep (sleeping hours the night before balance testing − average sleep hours during the week). All farmers performed four balance tests on either one foot or both feet and with eyes open or closed. Balance was measured using a pressure mat to monitor the change in center of pressure (CoP) of the feet in anteroposterior (AP) and mediolateral (ML) directions. Spearman’s rank correlation coefficient indicated balance outcomes were strongly and negatively correlated with the net sleep (P <.05). As the net sleep decreased, farmers became less stable, particularly indicated by an increase in the area, total displacement, and deviations of CoP in both AP and ML directions while standing on both feet with eyes open. Fisher’s exact test showed an association between the CoP in AP direction and the net sleep (P =.020, odds ratio [OR] = 7.37). Thus, the odds of having reduced balance stability were 7.4 times higher when farmers slept less than their average hours during the night prior to the balance test. These results suggest that acute sleep loss impacts balance stability that may lead to falls. Understanding the association of sleep loss and balance stability is important in prevention of agricultural injuries.