Skip to main content
OpenTrials
Completed

NCT Number: NCT05838014

Acute Sleep Deprivation on Whole-body Heat Exchange During Exercise-heat Stress in Young and Older Men

Sleep deprivation has long been thought to modulate thermoregulatory function. Seminal work on sleep deprivation and thermoregulation has demonstrated that sleep-deprived individuals experience greater elevations in core temperature during exercise-heat stress due to reductions in the activation of local heat loss responses of cutaneous vasodilation and sweating. However, it remains unclear 1) if reductions in local heat loss responses would compromise whole-body heat loss (evaporative + dry heat exchange) and 2) if differences exist, are they dependent on the heat load generated by exercise (increases in metabolic rate augments the rate that heat must be dissipated by the body). Further, much of the understanding of the effects of sleep deprivation on thermoregulation has been limited to assessments in young adults. Studies show that aging is associated with reduction in cutaneous vasodilation and sweating that compromise whole-body heat loss exacerbating body heat storage during moderate- and especially more vigorous-intensity exercise in the heat. However, it remains unclear if sleep deprivation may worsen this response in older adults.

The purpose of this study is therefore to evaluate the effects of sleep-deprivation on whole-body total heat loss during light, moderate, and vigorous exercise-heat stress and to assess if aging may mediate this response. To achieve this objective, direct calorimetry will be employed to measure whole-body total heat loss in young (18-30 years) and older (50-65 years) men during exercise at increasing, fixed rates of metabolic heat production of 150 (light), 200 (moderate), and 250 W/m2 (vigorous) in dry heat (40°C, ~15% relative humidity) with and without 24 hours of sleep deprivation.

Completed

Looking for future studies?

Notify Me

Key information

Conditions

Thermoregulation Aging Behavior Exercise Heat Exchange Heat Stress Disorders Mental Disorders Motor Activity Nervous System Diseases Parasomnias Sleep Disturbance Sleep Wake Disorders Wounds and Injuries

Age range

18 year–65 year

Sex eligibility

Male

Study type

Interventional

Phase

Not applicable

Primary location

University of Ottawa

Ottawa, Ontario, K1N6N5, Canada

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • healthy young (18-30 years) and older males (50-65 years)
  • non-smoking
  • English or French speaking
  • ability to provide informed consent

Exclusion criteria

  • presence of chronic diseases (e.g., hypertension, diabetes)
  • acute illness (e.g., flu, COVID-19)
  • physical restriction limiting physical activity (e.g., severe arthritis, etc.)
  • use of medication judged by the patient or investigators to make participation in this study inadvisable
  • engaged in regular endurance training

Treatment and study plan

Sleep deprivation

Other

Participants will undertake a period of 24 hours of total sleep deprivation prior to completing exercise

Normal sleep

Other

Participants will undertake ~8 hours of normal sleep prior to completing exercise

Primary outcomes

  1. Evaporative heat loss

    Time frame: End of each exercise bout (average of last 5 minutes)

    Evaporative heat loss as assessed using a direct air calorimeter

  2. Whole-body heat loss

    Time frame: End of each exercise bout (average of last 5 minutes)

    Net heat loss (dry plus/minus evaporative heat exchange) as assessed using a direct air calorimeter

Secondary outcomes

  1. Dry heat loss

    Time frame: End of each exercise bout (average of last 5 minutes)

    Total dry heat loss as assessed using a direct air calorimeter

  2. Body heat storage

    Time frame: Each 30 minute exercise bout and sum of all three exercise bouts

    Change in body heat storage (i.e., amount of heat stored in the body) calculated as the temporal summation of metabolic heat production and net heat loss

  3. Core temperature

    Time frame: End of each exercise bout (average of last 5 minutes)

    Rectal temperature measured as an index of core temperature

  4. Change in core temperature

    Time frame: End of each exercise bout (average of last 5 minutes)

    Change in rectal temperature from baseline resting

  5. Heart rate

    Time frame: End of each exercise bout (average of last 5 minutes)

    Measured continuously using a heart rate monitor

  6. Heart rate reserve

    Time frame: End of each exercise bout (average of last 5 minutes)

    Percentage of the difference between the peak heart rate

  7. Local sweat rate (forearm, scapula)

    Time frame: End of each exercise bout (average of last 5 minutes)

    Sweat production assessed using ventilated capsule technique

  8. Skin temperature

    Time frame: End of each exercise bout (average of last 5 minutes)

    Skin temperature measured continuously at 4-sites (chest, upper arm, thigh, calf) with mean value calculated as weighted value of 4 sites - bicep, 30%; chest, 30%; thigh, 20%; and calf, 20%.

  9. Skin temperature (change)

    Time frame: End of each exercise bout (average of last 5 minutes)

    Change in skin temperature from baseline resting as assessed at 4-sites (chest, upper arm, thigh, calf) with mean value calculated as weighted value of 4 sites - bicep, 30%; chest, 30%; thigh, 20%; and calf, 20%.

  10. Thermal comfort scale

    Time frame: End of the 30 minute resting baseline period, end of each 30 minute exercise bout, end of each 15 minute rest period, and 1 hour after final exercise period.

    Thermal comfort assessed via a self-report questionnaire upon verbal prompting (4-point scale; 1: comfortable to 4: very uncomfortable)

  11. Thermal sensation

    Time frame: End of the 30 minute resting baseline period, end of each 30 minute exercise bout, end of each 15 minute rest period, and 1 hour after final exercise period.

    Thermal sensation assessed via a self-report questionnaire upon verbal prompting (7-point scale; 0: neutral to 7: extremely hot)

  12. Thirst sensation

    Time frame: End of the 30 minute resting baseline period, end of each 30 minute exercise bout, end of each 15 minute rest period, and 1 hour after final exercise period.

    Thirst sensation assessed via a self-report questionnaire upon verbal prompting (9-point scale; 1: not thirsty at all to 9: very, very thirsty)

  13. Rating of perceived exertion

    Time frame: End of the 30 minute resting baseline period, end of each 30 minute exercise bout, end of each 15 minute rest period, and 1 hour after final exercise period.

    Perceived exertion assessed via a self-report questionnaire upon verbal prompting (6: no exertion at all to 20: maximal exertion)

  14. Stanford sleep scale

    Time frame: End of the 30 minute resting baseline period, end of each 30 minute exercise bout, end of each 15 minute rest period, and 1 hour after final exercise period.

    Symptoms of tiredness assess via a self-report questionnaire upon verbal prompting (How sleepy are you?) ranging from "feeling active, vital, alert, or wide awake" to "no longer fighting sleep, sleep onset soon, having dream-like thoughts"

  15. Variables of heart rate variability

    Time frame: End of each exercise (average of last 5 minutes)

    Measures of variability computed from the time, frequency, time-frequency, scale-invariant, entropy, and other nonlinear domains (R-R interval data extracted from the electrocardiogram)

Sponsors and collaborators

Lead sponsor

University of Ottawa

Other

Registry information

Official study title

The Effect of Sleep Deprivation on Whole-body Heat Loss in Young and Older Men During Exercise in Hot, Dry Conditions

Important dates

Study start
2022
Primary completion
2023
Study completion
2023
First posted
May 1, 2023
Registry last updated
Jul 15, 2024

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.