Effect of Hypohydration on Muscle Endurance, Strength, Anaerobic Power and Capacity and Vertical Jumping Ability: A Meta-Analysis.
Level 1 - systematic review of randomized trials
Meta-analysis of experimental trials
PubMed 26178327 · doi:10.1007/s40279-015-0349-0
What was done
A meta-analysis was conducted across 28 manuscripts identified via database searches and cross-referencing to determine the impact of hypohydration on upper and lower body muscle endurance, muscle strength, anaerobic power and capacity, and vertical jumping ability. Random-effects models were used to calculate effect summaries, method of moments mixed-effects ANOVA-like procedures evaluated subgroup differences, and restricted maximum likelihood random-effects meta-regressions analyzed confounders and interactions.
What was found
Hypohydration significantly impaired overall muscle endurance by 8.3 ± 2.3% (P < 0.05; upper body -8.4 ± 3.3%, lower body -8.2 ± 3.2%) and muscle strength by 5.5 ± 1.0% (P < 0.05; upper body -6.2 ± 1.1%, lower body -3.7 ± 1.8%). Anaerobic power decreased significantly by 5.8 ± 2.3%, whereas changes in anaerobic capacity (-3.5 ± 2.3%) and vertical jumping ability (0.9 ± 0.7%) were not statistically significant. Active dehydration caused an additional 5.4 ± 1.9% (P = 0.02) performance decrement compared to passive dehydration. Trained individuals showed a 3.3 ± 1.7% smaller decrement than untrained individuals (P = 0.06). No significant correlation was observed between the magnitude of hypohydration and the degree of performance change.
Why it matters
This review quantifies the specific performance costs of fluid deficit on non-bodyweight-supported strength and endurance tasks, demonstrating that dehydration mode substantially modifies the magnitude of performance loss.
Limits
Total participant count and demographic characteristics (such as sex and age) were not reported in the abstract. Active dehydration introduces exercise-induced fatigue as a confounding variable alongside fluid deficit. The lack of correlation between hypohydration magnitude and performance decrements suggests unexplained heterogeneity across protocols.
Cited by
- supports Even a slight degree of dehydration can impair cognitive and physical performance.