The effect of exercise intensity and fluid restriction on cognitive function and salivary measures in Division III male and female endurance athletes

This study examined cognitive and hormonal response to mild fluid restriction during exercise. Sixteen apparently healthy subjects had aerobic fitness and body composition determined. Treadmill exercise was paired with two fluid interventions in a randomized cross‐over design. Cognitive testing (Automated Neuropsychological Assessment Metrics) and saliva collection were completed prior to and immediately after exercise. Cognition was impacted by exercise evident in Code Substitution, Match to Sample (M2S), and Matching Grids tests. Fluid condition and a fluid condition and exercise interaction for M2S were significant. For the non‐fluid restricted condition, the moderate intensity exercise throughput value was 0.3 ± 3.5 (mean ± SD) and the value at high intensity was 6.5 ± 3.0. For the fluid restricted condition, the moderate intensity value was 11.6 ± 2.9 and the value at high intensity was 13.6 ± 4.6. Exercise elicited an increase in α‐amylase, cortisol, and testosterone. There was a fluid condition and gender interaction for α‐amylase. Fluid condition also impacted cortisol; the value for the non‐fluid restricted condition was 0.33 ± 0.03 ug/dL and for the fluid restricted condition was 0.38 ± 0.03 ug/dL. This research can be the basis for future studies focusing on athletes who are involved in sports in which performance is based on reaction and decision making.