Extreme heat events are a significant global threat to health and wellbeing, and result in more morbidity and mortality than all other natural disasters combined. Thus, a key priority is identifying effective and accessible heat resilience solutions to protect individuals from the potentially fatal consequences of heat stress. Within a range of ambient conditions, a fan has been recognized a low-cost heat resilience solution. However, when ambient temperatures exceed skin temperatures (e.g., above 35°C), a fan will incur greater dry heat gain which may be counterbalanced with evaporation of sweat from the skin surface. However, at a critical indoor temperature, the rate of heat gain will exceed the rate of evaporation resulting in net heat gain. The critical indoor temperature has yet to be determined. The purpose of this present study is to identify the indoor temperature at which a fan results in greater cardiovascular and thermal strain relative to still air in young adults using a simulated heat wave scenario of a warming room.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
10
Following a 45 minute baseline in 37°C seated on a chair, the indoor temperature in the climate-controlled room increased from 37°C to 47°C at \~0.06°C/min (relative humidity \~26%) over 180 minutes.
Lakehead University
Thunder Bay, Ontario, Canada
Blood Pressure
Measured with an electrocardiogram-gated automated cuff
Time frame: At baseline (e.g. 0 minutes), and every 10 minutes of exposure up to 180 minutes
Rate Pressure Product
Time frame: At baseline (e.g. 0 minutes), and every 10 minutes of exposure up to 180 minutes
Heart Rate
Measured with a 3-lead electrocardiogram
Time frame: At baseline (e.g. 0 minutes), and every minute for the 180 minute experimental trial
Skin Temperature
Measured at 4 skin locations (chest, arm, thigh, and calf) using wireless iButtons affixed to the skin with surgical tape
Time frame: At baseline (e.g. 0 minutes), and every minute for the 180 minute experimental trial
Core Temperature
rectal temperature measured with a pediatric grade thermistor probe
Time frame: At baseline (e.g. 0 minutes), and every minute for the 180 minute experimental trial
Whole-Body Sweat Rate
Net difference in body mass (pre versus post) using a balance scale placed below the chair of the participant
Time frame: At baseline (e.g. 0 minutes), and every minute for the 180 minute experimental trial
Thermal Sensation
visual analog scale
Time frame: At baseline (e.g. 0 minutes), and every 10 minutes for the 180 minute experimental trial
Thermal comfort
visual analog scale
Time frame: Assessed at baseline (e.g. 0 minutes), and every 10 minutes for the 180 minute experimental trial
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