Safe Indoor Temperature Limit for Fans

NCT06584903 | Completed

• 1 other identifier: 26897
• Study Type: interventional
• Target: 10
• Locations: 1 country
• Sites: 1

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.

Conditions

Heat Exposure; Healthy; Young Adults; Fans

Keywords

indoor temperature; core temperature; heart rate; electric fans; cardiovascular strain

Outcome Measures

Primary Outcomes (6)

• Blood Pressure

  Measured with an electrocardiogram-gated automated cuff

  At baseline (e.g. 0 minutes), and every 10 minutes of exposure up to 180 minutes

• Rate Pressure Product

  At baseline (e.g. 0 minutes), and every 10 minutes of exposure up to 180 minutes

• Heart Rate

  Measured with a 3-lead electrocardiogram

  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

  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

  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

  At baseline (e.g. 0 minutes), and every minute for the 180 minute experimental trial

Secondary Outcomes (2)

• Thermal Sensation

  At baseline (e.g. 0 minutes), and every 10 minutes for the 180 minute experimental trial

• Thermal comfort

  Assessed at baseline (e.g. 0 minutes), and every 10 minutes for the 180 minute experimental trial

Study Arms (2)

Still air

PLACEBO COMPARATOR

still air condition with no supplemental air flow

Other: Temperature Ramp Protocol

Electric fan

EXPERIMENTAL

Force air flow with a 46 cm 3-blade fan positioned 1.2 m anterior to the participants chest

Other: Temperature Ramp Protocol

Interventions

Temperature Ramp Protocol OTHER

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.

Electric fan; Still air

Eligibility Criteria

• Age: 19 Years - 39 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

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

You may not qualify if:

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

Sponsors & Collaborators

• Lakehead University: lead

Study Sites (1)

Lakehead University

Thunder Bay, Ontario, P7B 5E1, Canada

Location

Study Officials

• Nicholas Ravanelli, PhD

  National University of Singapore

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: PREVENTION
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor

Study Record Dates

• First Submitted: September 3, 2024
• First Posted: September 5, 2024
• Study Start: January 20, 2024
• Primary Completion: April 30, 2024
• Study Completion: April 30, 2024
• Last Updated: September 19, 2024

Record last verified: 2024-09

Data Sharing

• IPD Sharing: Will share
• Time Frame: Following publication
• Access Criteria: Anyone will be allowed to access the data supporting the findings through the Open Science Framework Repository.

Locations

CA (1)