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

Summary

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.

Conditions

• Thermoregulation
• Sleep Disturbance
• Heat Exchange
• Aging
• Exercise

Interventions

OTHER

Sleep deprivation

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

OTHER

Normal sleep

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

Sponsors & Collaborators

• University of Ottawa

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

65 Years

Sex

MALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2022-12-01

Primary Completion

2023-06-29

Completion

2023-06-29

Countries

• Canada

Study Locations