Impact of Indoor Overheating on Physiological Strain in Children
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age10-15
SponsorUniversity of Ottawa
About this trial
Communities worldwide are experiencing increasing heat extremes that challenge the limits of human thermoregulation, particularly among vulnerable populations such as children. Compared with adults, children are more susceptible to heat related illness due to less efficient thermoregulatory systems and difficulty recognizing early signs of heat stress. In addition, prolonged heat exposure can adversely affect their mental health, contributing to cognitive decline, heightened anxiety, and irritability. As children spend substantial time in hot environments at school and at home, and as these conditions intensify with climate change, actions to safeguard their health are essential. Yet our understanding of heat exposure effects in children remains incomplete, hindering the development of evidence based strategies to protect them.
To address this gap, the investigators aim to evaluate whether an indoor temperature limit of 26 °C (45 percent relative humidity), the upper threshold recommended to protect older adults, can effectively prevent dangerous increases in physiological strain and declines in cognitive function in children during a simulated daylong heatwave. The preliminary study will assess physiological and cognitive responses in children aged 10 to 15 years during a 6 hour exposure (approximating a typical school day) to two conditions: (1) the recommended indoor temperature upper limit (26 °C) and (2) a high heat condition representative of homes and schools without air conditioning during extreme heat events (36 °C). In both conditions, children will remain seated at rest while wearing light clothing (t shirt and shorts), with the exception of performing 15 minutes of stepping exercise (6-6.5 METS) each hour (excluding the lunch period) to reflect typical daily activity in a school setting. This experimental design will allow investigators to determine whether maintaining indoor temperatures at the recommended upper limit for older adults sufficiently mitigates physiological strain in children.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
English or French speaking.
Ability to provide informed assent.
Disqualifiers
Chronic health conditions
Endurance exercise training (greater than 3 sessions of vigorous exercise training per week for 30 minutes or more)
Restrictions to physical activity
Trial design
Design model
Crossover
Treatments tested in this trial
Simulated exposure to indoor overheating
Other interventionChildren exposed to a 6-hour simulated heat exposure
Treatment groups
10 Participants
are divided into 2 treatment groupsGroup A: Exposure to indoor temperature upper limit of 26°CExperimental treatment 1 intervention
Group B: Exposure to hot indoor environment of 36°CExperimental treatment 1 intervention
Trial outcomes
Primary outcomes
1
Core temperature (Peak) during daylong exposure to indoor overheating
Peak visceral temperature (15 min average) during exposure. Visceral temperature is measured continuously throughout the 6 hour exposure to the simulated indoor overheating.
Time frame
End of 6 hour daylong exposureSecondary outcomes
1
Profiles of Mood States (POMS) during daylong exposure to indoor overheating
Potential changes in mood (7 subscales of mood: tension, anger, depression, fatigue, confusion, vigor and esteem related affect). The POMS-40 is a validated, self-administered questionnaire that examines seven distinct aspects of mood state across two positive subscales (Esteem-Related Affect, and Vigor) and five negative subscales (Fatigue, Tension, Confusion, Anger, and Depression), which are described across 40 distinct adjectives. For each individual item, participants were asked to describe "how you feel right now" by responding using a 5-point Likert scale (0 = "Not at all", 1 = "A little", 2 = "Moderately", 3 = "Quite a lot", or 4 = "Extremely"). The values of items associated with a specific subscale (e.g., Fatigue) were summed to calculate its score.
Time frame
At the start (hour 0) and end of 6 hour daylong exposure2
Environmental Symptoms Questionnaire (ESQ) during daylong exposure to indoor overheating
Self-reported environmental reactions and medical symptomatology associated with prolonged heat exposure. The ESQ-IV is a validated 68-item, self-administered questionnaire that has been used successfully in identifying symptomatology during exposure to a wide variety of environmental conditions, including heat exposure. Participants are asked to assess and described "how you have been feeling today" by responding to each item using a 6-point Likert scale (0 = "Not at all", 1 = "Slight", 2 = "Somewhat", 3 = "Moderate", 4 = "Quite a bit", or 5 = "Extreme"). Total Symptom Score was calculated from this data by taking the sum of the intensity ratings from all 68 individual items using reverse scores for the three positive items from the list ("I Felt Good", "I Felt Alert", and "I Felt Wide Awake").
Time frame
At the start (hour 0) and end of 6 hour daylong exposure3
Perceived exertion scale during daylong exposure to indoor temperature limit.
Perceived exertional assessed via a visual analog scale ("How hard are you working?") ranging from "no exertional at all" to "maximal exertion"
Time frame
At the start (hour 0) and end of 6 hour daylong exposure4
Activity levels during daylong exposure to indoor overheating
Activity levels assessed via a wearable monitor (Actical) containing an accelerometer worn on the wrist and hip.
Time frame
End of 6 hour daylong exposureSponsors and contacts
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Source ClinicalTrials.gov