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 Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Enrollment
34
Participants rest in a climate controlled room maintained at 40°C and 30%RH for 120 minutes follow placebo beverage consumption (180 minutes total).
Participants rest in a climate controlled room maintained at 40°C and 30%RH for 120 minutes follow alcoholic beverage consumption (180 minutes total).
Lakehead University
Thunder Bay, Ontario, Canada
RECRUITINGHeart Rate
3-lead electrocardiogram
Time frame: measured at baseline (pre drink), and every 30 minutes following consumption (up to 120 minutes).
Skin Temperature
Mean skin (4 sites)
Time frame: measured at baseline (pre drink), and every 30 minutes following consumption (up to 120 minutes).
Core Temperature
measured rectally
Time frame: measured at baseline (pre drink), and every 30 minutes following consumption (up to 120 minutes).
Blood Pressure
ECG-gated blood pressure cuff
Time frame: measured at baseline (pre drink), and every 30 minutes following consumption (up to 120 minutes).
Heart Rate Variability
Time frame: measured at baseline (pre drink), and every 30 minutes following consumption (up to 120 minutes).
Arrythmia presence
Time frame: 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
Time frame: 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
Time frame: measured at baseline (pre drink), and every 30 minutes following consumption (up to 120 minutes).
Skin Blood Flow
Time frame: measured at baseline (pre drink), and every 30 minutes following consumption (up to 120 minutes).
Urine Output
Time frame: Total urine output (e.g. volume) from baseline to immediately following 120 minutes of heat stress
ASHRAE seven-point thermal sensation scale
Time frame: 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
Time frame: measured at baseline (pre drink), and every 30 minutes following consumption (up to 120 minutes).
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
Time frame: 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
Time frame: measured at baseline (pre drink), and every 30 minutes following consumption (up to 120 minutes).
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