Safe Indoor Temperature Limit for Fans

Not Applicable

Completed

• Conditions: Heat Exposure; Healthy; Young Adults; Fans
• Interventions: Other: Temperature Ramp Protocol

• Registration Number: NCT06584903
• Lead Sponsor: Lakehead University

Brief Summary

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.

Detailed Description

Not available

Study Timeline

• Study Start: 2024-01-20
• Primary Completion: 2024-04-30
• Study Completion: 2024-04-30
• Status Verified: 2024-09
• Study First Submitted: 2024-09-03
• Study First Submitted QC: 2024-09-03
• Last Update Submitted: 2024-09-03
• Study First Posted: 2024-09-05
• Last Update Posted: 2024-09-05

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 10

Inclusion Criteria

• Body mass index less than 30
• male or female
• ability to tolerate hot environments for a prolonged period (e.g. >2 h)

Exclusion Criteria

• Any respiratory disease
• Any cardiovascular disease, including hypertension
• Diabetes
• not currently on any medication (except oral contraceptives)

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Still air	Temperature Ramp Protocol	still air condition with no supplemental air flow
Electric fan	Temperature Ramp Protocol	Force air flow with a 46 cm 3-blade fan positioned 1.2 m anterior to the participants chest

Primary Outcome Measures

Name	Time	Method
Blood Pressure	At baseline (e.g. 0 minutes), and every 10 minutes of exposure up to 180 minutes	Measured with an electrocardiogram-gated automated cuff
Rate Pressure Product	At baseline (e.g. 0 minutes), and every 10 minutes of exposure up to 180 minutes
Heart Rate	At baseline (e.g. 0 minutes), and every minute for the 180 minute experimental trial	Measured with a 3-lead electrocardiogram
Skin Temperature	At baseline (e.g. 0 minutes), and every minute for the 180 minute experimental trial	Measured at 4 skin locations (chest, arm, thigh, and calf) using wireless iButtons affixed to the skin with surgical tape
Core Temperature	At baseline (e.g. 0 minutes), and every minute for the 180 minute experimental trial	rectal temperature measured with a pediatric grade thermistor probe
Whole-Body Sweat Rate	At baseline (e.g. 0 minutes), and every minute for the 180 minute experimental trial	Net difference in body mass (pre versus post) using a balance scale placed below the chair of the participant

Secondary Outcome Measures

Name	Time	Method
Thermal Sensation	At baseline (e.g. 0 minutes), and every 10 minutes for the 180 minute experimental trial	visual analog scale
Thermal comfort	Assessed at baseline (e.g. 0 minutes), and every 10 minutes for the 180 minute experimental trial	visual analog scale

Trial Locations

Locations (1)

Lakehead University; 🇨🇦 Thunder Bay, Ontario, Canada