Autonomic Adaptation to Hydration and Brain Functioning
Autonomic Adaptation to Hydration and Brain Functioning
The influence of relatively small decreases in hydration status have been little studied. On two occasions subjects will be allowed to lose about 0,5% of their body weight and one occasion 300ml of water will be consumed. Functional MRI will be used to monitor brain functioning when performing a mental arithmetic task. Heart rate variability will be monitored and related to differences in brain functioning when water has and has not been drunk
On two mornings twelve male participants will be exposed to a temperature of 30oC for four hours and either drink or not drink two 150ml glasses of water during that time. The subjects the participate in an fMRI protocol during which they complete a modified version of the Paced Auditory Serial Addition Test (PASAT): a challenging arithmetic task designed to elicit autonomic arousal.
Throughout the morning subjects will their heart rate variability (HRV) monitored. At periodic intervals subjects will rate their thirst and mood by visual analogue scales and at the end of the PASAT task they rate its difficulty. Changes in body temperature and fluid loss (perspiration and urine) and urine osmolality will be monitored.
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