Ethanol Consumption in the Heat

Evaluating How Alcohol Impacts Physiological Responses and Perception During Heat Exposure

Climate change has significantly increased the earth's average surface temperature and heat waves have been predicted to increase in frequency, intensity and duration. Extreme heat events have increased the susceptibility to heat-related illnesses, such as heat exhaustion, heat stroke or death. Heat health action plans have been designed to advertise cooling behaviours to mitigate physiological strain. Heat health action plans suggest avoiding alcohol consumption during extreme heat as it may increase dehydration and impair behavioural or physiological temperature regulation and thermal perception. Regardless of these messages, alcohol sales continue to remain high during the summer months year after year, and 1/5 of adults identify alcohol as a hydration strategy during extreme heat events. A recent scoping review investigating the effects of alcohol and heat has demonstrated that acute alcohol consumption does not negatively influence thermoregulation, hydration, or hormone markers of fluid balance in the heat compared to a control fluid (https://doi.org/10.1186/s12940-024-01113-y). Further, alcohol consumption may elicit sex- and age-specific alterations in physiological and perceptual responses, neither of which have been explored.

Therefore, this study aims to comprehensively evaluate how alcohol consumption systematically alters physiological responses and perceptions during conditions similar to those experienced indoors during extreme heat events in younger and older adults.

Study Overview

• Status: Recruiting
• Conditions: Alcohol Consumption; Heat Stress; Age
• Intervention / Treatment: Drug: Placebo Beverage; Drug: Alcohol (Ethanol)

• Study Type: Interventional
• Enrollment (Estimated): 34
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Nicholas Ravanelli, PhD; Phone Number: 18073438010; Email: nravanel@nus.edu.sg

Study Locations

• Canada
  • Ontario
    • Thunder Bay, Ontario, Canada, P7B 5E1
      • Recruiting
      • Lakehead University
      • Contact: Nicholas Ravanelli, PhD; Phone Number: 8073438010; Email: nravanel@nus.edu.sg
      • Contact: KarLee Lefebvre, BHK
      • Contact: Amy Brough, BHK
      • Contact: Taryn Klarner, BHK
      • Contact: Nathan Morris, PhD
      • Contact: Georgia Chaseling, PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Male or Female above the age of 19
• Able to provide informed consent

Exclusion Criteria:

• History of cardiovascular disease, cancer, type 1 or 2 diabetes, chronic obstructive pulmonary disorder, cystic fibrosis, or alcohol addiction or dependence
• Been hospitalized due to COVID-19
• Pregnant/Breastfeeding
• Scoring an eight or above on the Alcohol Use Disorders Identification Test (AUDIT)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo; Placebo (non-alcoholic beverage)	Drug: Placebo Beverage; Participants rest in a climate controlled room maintained at 40°C and 30%RH for 120 minutes follow placebo beverage consumption (180 minutes total).
Active Comparator: Alcohol; Consumption of alcohol beverages: females 0.75 ± 0.1 grams of ethanol/kilogram body mass; males 1.0 ± 0.1 grams of ethanol/kilogram body mass	Drug: Alcohol (Ethanol); Participants rest in a climate controlled room maintained at 40°C and 30%RH for 120 minutes follow alcoholic beverage consumption (180 minutes total).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Heart Rate	3-lead electrocardiogram	measured at baseline (pre drink), and every 30 minutes following consumption (up to 120 minutes).
Skin Temperature	Mean skin (4 sites)	measured at baseline (pre drink), and every 30 minutes following consumption (up to 120 minutes).
Core Temperature	measured rectally	measured at baseline (pre drink), and every 30 minutes following consumption (up to 120 minutes).
Blood Pressure	ECG-gated blood pressure cuff	measured at baseline (pre drink), and every 30 minutes following consumption (up to 120 minutes).
Heart Rate Variability		measured at baseline (pre drink), and every 30 minutes following consumption (up to 120 minutes).
Arrythmia presence		measured at baseline (pre drink), and every 30 minutes following consumption (up to 120 minutes).
Whole-body Sweat Loss	Difference in mass from baseline to end heat stress	mass measured at baseline and end heat stress.
Postural Sway via the Romberg Test	The total movement of the body around the center of mass with feet together	measured at baseline (pre drink), and every 30 minutes following consumption (up to 120 minutes).
Skin Blood Flow		measured at baseline (pre drink), and every 30 minutes following consumption (up to 120 minutes).
Urine Output		Total urine output (e.g. volume) from baseline to immediately following 120 minutes of heat stress
ASHRAE seven-point thermal sensation scale		measured at baseline (pre drink), and every 30 minutes following consumption (up to 120 minutes).
5-Point Thermal Comfort Scale	Thermal comfort scale with 1- comfortable and 5 - very uncomfortable	measured at baseline (pre drink), and every 30 minutes following consumption (up to 120 minutes).

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Subjective Blood Alcohol Concentration (visual analog scale 0.0 - 0.20)	Visual analog scale with left and right anchors of 0.0 and 0.20, respectively, with markers every 0.005 increment	measured at baseline (pre drink), and every 30 minutes following consumption (up to 120 minutes).
Blood Alcohol Concentration	Measured using a police grade portable breathalyzer	measured at baseline (pre drink), and every 30 minutes following consumption (up to 120 minutes).

Collaborators and Investigators

• Sponsor: Lakehead University

Publications and helpful links

General Publications

• Morris NB, Ravanelli N, Chaseling GK. The effect of alcohol consumption on human physiological and perceptual responses to heat stress: a systematic scoping review. Environ Health. 2024 Sep 12;23(1):73. doi: 10.1186/s12940-024-01113-y. Erratum In: Environ Health. 2024 Oct 15;23(1):85. doi: 10.1186/s12940-024-01129-4.

Study record dates

Study Major Dates

• Study Start (Actual): December 4, 2023
• Primary Completion (Estimated): August 1, 2025
• Study Completion (Estimated): August 1, 2025

Study Registration Dates

• First Submitted: April 1, 2025
• First Submitted That Met QC Criteria: April 11, 2025
• First Posted (Actual): April 18, 2025

Study Record Updates

• Last Update Posted (Actual): April 18, 2025
• Last Update Submitted That Met QC Criteria: April 11, 2025
• Last Verified: April 1, 2025

More Information

Terms related to this study

• Keywords: alcohol; core temperature; perception; heat wave; behaviour; sweating; heat stress; micturition
• Additional Relevant MeSH Terms: Wounds and Injuries; Drinking Behavior; Alcohol Drinking; Heat Stress Disorders; Anti-Infective Agents; Physiological Effects of Drugs; Central Nervous System Depressants; Anti-Infective Agents, Local; Ethanol
• Other Study ID Numbers: 1469888

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Deidentified data will be shared on the Open Science Framework following publication of results
• IPD Sharing Access Criteria: Anyone will have access

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No