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

NCT ID: NCT05838014

Last Updated: 2024-07-15

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 21 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2022-12-01
• Study Completion Date: 2023-06-29

Brief 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

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: NONE

Study Groups

Normal sleep

Participants will complete three 30-minute bouts of semi-recumbent cycling at incrementally increasing fixed metabolic heat loads (150, 200 and 250 W/m2) in a hot, dry condition (40°C, 15% relative humidity). Each exercise bout will be separated by a 15 minute period of rest, with the final recovery 1 hour in duration. Exercise will commence between the hours of 7 AM and 9 AM following a period of normal sleep (\~8 hours) (Control condition).

Group Type: ACTIVE_COMPARATOR

Normal sleep

Intervention Type: OTHER

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

Sleep deprivation

Participants will complete three 30-minute bouts of semi-recumbent cycling at incrementally increasing fixed metabolic heat loads (150, 200 and 250 W/m2) in a hot, dry condition (40°C, 15% relative humidity). Each exercise bout will be separated by a 15 minute period of rest, with the final recovery 1 hour in duration. Exercise will commence between the hours of 7 AM and 9 AM following a period of 24 hour of sleep deprivation (Sleep deprivation condition).

Group Type: EXPERIMENTAL

Sleep deprivation

Intervention Type: OTHER

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

Interventions

Sleep deprivation

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

Intervention Type: OTHER

Normal sleep

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

Intervention Type: OTHER

Eligibility Criteria

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

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 65 Years
• Eligible Sex: MALE
• Accepts Healthy Volunteers: Yes

Sponsors

University of Ottawa

OTHER

Sponsor Role: lead

Responsible Party

Glen P. Kenny

Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

University of Ottawa

Ottawa, Ontario, Canada

Countries

Canada

Other Identifiers

HEPRU-2023-01

Identifier Type: -

Identifier Source: org_study_id