Physiological and Thermoregulatory Responses of Body Cooling During Cycling in a Hot Environment

NCT04715711 | Completed

• 1 other identifier: H20-0168
• Study Type: interventional
• Target: 12
• Locations: 1 country
• Sites: 1

Brief Summary

BHSAI is developing a computational system that provides early alerts of a rise in core body temperature to help reduce the risk of heat injury in the field and during training. The goal of the body temperature alerting system is to use it during rest, exercise in the heat and during body cooling. Using this system during cooling will allow healthcare professionals and military personnel monitor core temperature to ensure cooling is effective (and prevent hypothermia). Therefore, the primary purpose of this investigation is to validate a body temperature alerting system using physiological responses that occur during rest, exercise in the heat and during body cooling. Multiple cooling modalities will be validated. This study is expanding on a previous intervention IRB#H20-0010 (BHSAI Cooling Study), but will examine body cooling during more intense exercise and while cycling. We will also examine the effectiveness of each cooling modality (passive cooling, mist-fan cooling, hand/forearm immersion, ice towel) on physiological variables after exercise in the heat.

Conditions

Hyperthermia

Outcome Measures

Primary Outcomes (7)

• Difference in VO2max between Cycle ergometer and treadmill

  Participants will be fitted with a Hans Rudolph mask attached to a breathing tube to measure the expired air delivered to the metabolic cart system during the exercise protocol. The metabolic cart will continuously measure oxygen consumption (VO2) to asess their VO2max value.

  At the end of exercise test for both cycle ergometer and treadmill

• Metabolic Heat Production

  Participants will be tested for 3-5 minutes at different % of their VO2max. It will include 5 stages.

  Will be measured continuously throughout the 25 min exercise protocol.

• Change in Rectal Temperature

  Rectal thermometer will be self-inserted by participant to assess core temperature

  Measured continuously during two, 40 min exercise blocks and 2 20-30 min cooling periods.

• Change in Esophageal Temperature

  Esophageal thermometer will be inserted by a researcher to assess core temperature

  Measured continuously during two, 40 min exercise blocks and 2 20-30 min cooling periods

• Change in Heart Rate

  A heart rate monitor will be worn by participant throughout exercise/cooling protocol

  Measured continuously during two, 40 min exercise blocks and 2 20-30 min cooling periods

• Change in Mean Skin temperature

  Prior to the start of exercise, participants will be instrumented with 9-site (Biopac) and 6-site skin temperature (iButton) sensors. The Biopac skin temperature sensors will be placed on the chest, shoulder, forearm, abdomen, neck, back, thigh and anterior calf and posterior calf. and the iButton skin temperature sensors will be placed on the chest, arm, thigh, and anterior calf and posterior calf.

  Measured continuously during two, 40 min exercise blocks and 2 20-30 min cooling periods

• Change in Rating of Perceived Exertion

  6-20 scale that indicates how hard the participant feels they are working. 6 represents rest and 20 represents maximal exertion. A high score indicates more perceived exertion.

  Every 10 minutes of the exercise blocks (2 x 40 mins) and cooling period (2 x 20-30 min)

Secondary Outcomes (3)

• Change in Thermal Sensation

  Every 10 minutes of the exercise blocks (2 x 40 mins) and cooling period (2 x 20-30 min)

• Change in Perception of Fatigue

  Every 10 minutes of the exercise blocks (2 x 40 mins) and cooling period (2 x 20-30 min)

• Change in Perception of thirst

  Every 10 minutes of the exercise blocks (2 x 40 mins) and cooling period (2 x 20-30 min)

Study Arms (2)

Active Cooling

ACTIVE COMPARATOR

Participants will be actively cooled during rest breaks

Other: Forearm coolng; Other: Wet-towel cooling; Other: mist-fan

No Intervention

PLACEBO COMPARATOR

Participants will participant in "passive cooling" where they sit in a chair during rest.

Other: passive cooling

Interventions

Forearm coolng OTHER

forearm immersion will be performed for active cooling assessment

Active Cooling

Wet-towel cooling OTHER

Wet towels will be wrapped around the participant's arms for active cooling

Active Cooling

mist-fan OTHER

a mist-fan will be placed in front of the participant for active cooling

Active Cooling

passive cooling OTHER

participants will sit in a chair and "passively cool" (no active intervention)

No Intervention

Eligibility Criteria

• Age: 18 Years - 28 Years
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Cisgender man between the ages of 18-28 years
• been cleared by the medical monitor for this study
• VO2max \> 45ml/kg/min
• Aerobically active (at least 30 minutes of aerobic exercise 4-5 days per week)

You may not qualify if:

• Have a current musculoskeletal injury that would limit their physical activity or preclude the participant from walking, jogging, running, sprinting, or cutting.
• Chronic health problems that affect your ability to thermoregulate (disorders affecting the liver, kidneys or the ability to sweat normally)
• Fever or current illness at the time of testing
• History of cardiovascular, metabolic, or respiratory disease
• A family member died for no apparent reason, had a heart attack, died from heart problems, or sudden death before the age of 50
• Current musculoskeletal injury that limits their physical activity
• Currently taking a medication that is known to influence body temperature (amphetamines, antihypertensives, anticholinergics, acetaminophen, diuretics, NSAIDs, aspirin)
• Identify as cisgender woman, transgender man or transgender woman. Cisgender women, Transgender men, and transgender women are excluded from the current study because the sponsor of the study has requested that this testing be done in physically active cisgender males. It is assumed that they either currently have data on women or transgender women/men to compare this to or have a strategic initiative from a marketing or business perspective that only involves cisgender men.
• Have a history of heat related illness
• Throat or gastroesophageal diseases including gastroesophageal reflux disease (aka, GERD) or difficulty swallowing
• Have any allergies or adverse reactions to the cold (e.g. Cold Uticaria, Raynauds Phenomenon/Disease, or Cryoglobulinanemia)

Sponsors & Collaborators

• University of Connecticut: lead
• BHSAI: collaborator

Study Sites (1)

Korey Stringer Institute, University of Connecticut

Storrs, Connecticut, 06269, United States

Location

MeSH Terms

Conditions

Hyperthermia

Condition Hierarchy (Ancestors)

Body Temperature Changes; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Heat Stress Disorders; Wounds and Injuries

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Model Details: Participants received four cooling treatments on separate study visits: 1) passive cooling 2) forearm cooling 3) mist-fan cooling, 4) ice towel coolng

Study Record Dates

• First Submitted: January 14, 2021
• First Posted: January 20, 2021
• Study Start: April 2, 2021
• Primary Completion: July 19, 2021
• Study Completion: July 19, 2021
• Last Updated: August 3, 2021

Record last verified: 2021-08

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)