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

Aging Clinical Trial

Official title:

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

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT05838014
• Other study ID #: HEPRU-2023-01
• Status: Recruiting
• Phase: N/A
• Start date: December 1, 2022
• Est. completion date: August 31, 2023

Study information

• Verified date: April 2023
• Source: University of Ottawa
• Contact: Glen P Kenny, PhD
• Phone: 6135625800
• Email: gkenny[@]uottawa.ca
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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.

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 20
• Est. completion date: August 31, 2023
• Est. primary completion date: August 31, 2023
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Male
• Age group: 18 Years to 65 Years

Eligibility

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

Related Conditions & MeSH terms

• Aging
• Dyssomnias
• Exercise
• Parasomnias
• Sleep Deprivation
• Sleep Disturbance
• Thermoregulation

Intervention

Other:
• Sleep deprivation
Participants will undertake a period of 24 hours of total sleep deprivation prior to completing exercise
• Normal sleep
Participants will undertake ~8 hours of normal sleep prior to completing exercise

Locations

Country	Name	City	State
Canada	University of Ottawa	Ottawa	Ontario

Sponsors (1)

Lead Sponsor	Collaborator
University of Ottawa

Country where clinical trial is conducted

Canada, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Evaporative heat loss	Evaporative heat loss as assessed using a direct air calorimeter	End of each exercise bout (average of last 5 minutes)
Primary	Whole-body heat loss	Net heat loss (dry plus/minus evaporative heat exchange) as assessed using a direct air calorimeter	End of each exercise bout (average of last 5 minutes)
Secondary	Dry heat loss	Total dry heat loss as assessed using a direct air calorimeter	End of each exercise bout (average of last 5 minutes)
Secondary	Body heat storage	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	Each 30 minute exercise bout and sum of all three exercise bouts
Secondary	Core temperature	Rectal temperature measured as an index of core temperature	End of each exercise bout (average of last 5 minutes)
Secondary	Change in core temperature	Change in rectal temperature from baseline resting	End of each exercise bout (average of last 5 minutes)
Secondary	Heart rate	Measured continuously using a heart rate monitor	End of each exercise bout (average of last 5 minutes)
Secondary	Heart rate reserve	Percentage of the difference between the peak heart rate	End of each exercise bout (average of last 5 minutes)
Secondary	Local sweat rate (forearm, scapula)	Sweat production assessed using ventilated capsule technique	End of each exercise bout (average of last 5 minutes)
Secondary	Skin temperature	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%.	End of each exercise bout (average of last 5 minutes)
Secondary	Skin temperature (change)	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%.	End of each exercise bout (average of last 5 minutes)
Secondary	Thermal comfort scale	Thermal comfort assessed via a self-report questionnaire upon verbal prompting (4-point scale; 1: comfortable to 4: very uncomfortable)	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.
Secondary	Thermal sensation	Thermal sensation assessed via a self-report questionnaire upon verbal prompting (7-point scale; 0: neutral to 7: extremely hot)	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.
Secondary	Thirst sensation	Thirst sensation assessed via a self-report questionnaire upon verbal prompting (9-point scale; 1: not thirsty at all to 9: very, very thirsty)	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.
Secondary	Rating of perceived exertion	Perceived exertion assessed via a self-report questionnaire upon verbal prompting (6: no exertion at all to 20: maximal exertion)	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.
Secondary	Stanford sleep scale	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"	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.
Secondary	Variables of heart rate variability	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)	End of each exercise (average of last 5 minutes)