Prolonged mild hypohydration reduces handgrip strength in females

(In-Person) Poster Presentation 

An overwhelming majority of studies pertaining to the effects of hypohydration, a state of low body water, on muscular strength has been performed in males. One study recently reported that passive heat-stress induced hypohydration reduces upper-body muscular strength in females. It remains unknown whether hypohydration independent of heat stress elicits similar effects in females. We tested the hypothesis that maximal voluntary isometric handgrip strength is reduced in females following prolonged mild hypohydration compared to a hydrated state (i.e., euhydrated). Six healthy, physically active females performed two randomized experimental trials following either 24 hours of fluid deprivation (HYPO) or when euhydrated (EUHY). Subjects performed three attempts of maximal voluntary isometric handgrip strength with one minute rest between sets. Handgrip strength was evaluated as the maximum force produced and as the mean value of the three attempts. There were greater reductions in body mass in HYPO vs. EUHY (EUHY: -0.6±0.6%; HYPO: -2.2±0.6%, P=0.013), indicating that the 24-hour protocol induced a mild hypohydration in HYPO. Maximal handgrip strength was reduced in HYPO compared to EUHY (EUHY: 31±3 kg; HYPO: 28±5 kg, P=0.067) and there was a trend toward reduced mean handgrip strength (EUHY: 29±4 kg; HYPO: 26±6 kg, P=0.172). These preliminary findings suggest that prolonged hypohydration caused by inadequate fluid consumption reduces handgrip strength in females.