Hydration status affects mood state and pain sensation during ultra-endurance cycling In laboratory studies, it was postulated that dehydration influences the mood situation. In a field study with 119 cyclists, which drove over 161 km, it was investigated whether there could be a connection between dehydration and mood.
It clearly showed that dehydrated drivers suffered from more fatigue and pain than non-dehydrated drivers. The interesting work can be found under https://pubmed.ncbi.nlm.nih.gov/25793570/