ObjectivePrevious research has shown that dehydration is associated with impairment of mood. However, the effect of habitual total fluid intake (TFI) on mood in a population of adults with a wide range of TFI remains to be clarified.We evaluated the association between TFI and mood, task difficulty, concentration, thirst, and headaches in a cross‐sectional cohort of healthy adults. We hypothesized that greater TFI would be associated with better mood outcomes.MethodsSedentary free‐living healthy adults (n=82, mean age=23.6±2.9 years, mean BMI=22.2±1.5kg/m2) with a wide range of TFI (50 to 200% of EFSA recommendations) were recruited to take part in this study. Participants were asked to avoid engaging in physical activity and to maintain their normal food and fluid intake for 3 days during which food and TFI were recorded at home using an e‐diary (NutriSaas‐24WQ‐waters; MXS, France). Mean TFI ranged from 0.687 to 4.35L/day. On the third day, participants completed 6 questionnaires including the Profile of Mood State, Bond and Lader, emotional VAS, task difficulty and concentration VAS, sleep VAS, and thirst and headache VAS. Spearman or Pearson's correlations adjusted on sex between TFI and questionnaire scores were calculated.ResultsGreater TFI was significantly correlated with POMS score of vigor (r=0.334, p=0.002), anger (r=‐0.228, p=0.04) and total mood disturbance (r=‐0.284, p=0.01), with Bond and Lader scores of alertness (r=‐0.239, p=0.032) and contentedness (r=‐0.292, p=0.008), and with score of emotional VAS (r=0.310, p=0.005).ConclusionIndividuals with greater TFI felt happier, more contented and less angry, more alert and vigorous, and more generally in better mood.This study was funded by Danone Research, France.