Alcohol use is prevalent in working populations who are at risk of heat-related illnesses. There is a gap in the literature exploring how previous night alcohol consumption impacts perceptual responses to prolonged exertional heat stress. STUDY OBJECTIVE & HYPOTHESIS: We tested the hypothesis that previous night alcohol consumption would increase perceptions of exertion, heat strain, and symptoms of alcohol hangover during prolonged physical activity in the heat when compared to a control trial. METHODOLOGY: We utilized a randomized crossover design where 12 participants (7 females) completed two experimental trials consisting of four hours of walking in the heat (dry bulb temperature: 38°C, relative humidity: 40%) after a night of alcohol consumption (target blood alcohol content ≥0.11) or 48 h of no alcohol consumption (control). Trials included four one-hour cycles where participants walked for 20 minutes at an intensity corresponding to a metabolic rate of 4 W/kg, 10 minutes at 8 W/kg, 20 minutes at 4 W/kg, then 10 minutes of seated rest. Symptoms of alcohol hangover were assessed at baseline using a validated 12-item self-report questionnaire. Skin temperature (Tskin), rectal temperature (Trec), rating of perceived exertion (RPE), thermal sensation (TS), and thermal comfort (TC) were recorded every 10 minutes. A validated 12-item environmental symptoms questionnaire was assessed at baseline and during rest periods. RESULTS: Total symptoms of alcohol hangover were greater following a night of alcohol consumption (median score: 3), compared to control (median score: 1) (p = 0.002). Specific elevated symptoms included fatigue, apathy, concentration problems, clumsiness, confusion, stomach pain, nausea, and dizziness (p < 0.05). Alcohol increased Tskin (average difference: 0.4°C, effect of condition: p = 0.003) and Trec (average difference: 0.2°C, effect of condition: p = 0.02) during the exertional heat trial. There was no effect of condition for RPE (p = 0.07) or TS (p = 0.14). However, there was an effect of condition (p = 0.006) on TC which was greater in the alcohol condition (control: 1.7 ± 0.8, alcohol: 2.2 ± 0.9). Alcohol consumption increased environmental symptoms, as the median total score was nearly twice as high in the alcohol (45) compared to the control condition (25) (p = 0.005). Specific exacerbated symptoms included feeling warm, weak, lightheaded, irritable, nauseous, and impaired balance (p < 0.05). CONCLUSIONS: These findings demonstrate that previous night alcohol consumption elevates Trec and Tskin and increases discomfort and environmental symptoms. Differences in discomfort and environmental symptoms from previous night alcohol consumption may be due to elevations in Trec and Tskin. Safety personnel and workers should be aware of the elevated physiological and perceptual heat strain following previous night alcohol use. FUNDING SOURCES: This study was partially funded by the University of New Mexico’s Research Allocations Committee (to FTA), Graduate and Professional Student Association (to JWS), and Graduate Studies (to JWS). This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.
Clark et al. (Fri,) studied this question.