Study to Warm Up and Cool Down Recreationally Active Males Using Different Protocols.

Not Applicable

Completed

• Conditions: Heat Acclimation and Thermotolerance

• Registration Number: NCT06874023
• Lead Sponsor: Arizona State University

Brief Summary

The objective of this study was to examine the impact of four single-bout heating and cooling strategies on warming up and cooling down core body temperature. Heating strategies included: Passive heating in a hot environment (60 min), Active heating (30 min) + passive heating (30 min) in a hot environment, Active heating(60 min) in a hot environment, and Active heating (60 min) at room temperature. Cooling strategies to reduce body core temperature to baseline included: Cool vest (18°C) , Damp neck towel (24°C) combined with arm (i.e. hand, forearm and half of upper arm) cool water immersion (15°C), Combination of both, A control with participant sitting in a thermoneutral room (20°C air temperature) without any additional cooling intervention.

Detailed Description

This semi-randomized crossover control trial was performed between September and October 2020. Data collection took place over the course of 5-weeks with 10 subjects, with one data collection session with all subjects per week (hence, 40 trials total). Baseline gastrointestinal temperature (Tgi) was recorded, and the final Tgi at the end of the heating intervention (Part I), was used as the starting temperature for the current study (Part II).

Part I focused on assessing the efficacy of different heating strategies (Passive heating in a hot environment (60 min), Active heating (30 min) + passive heating (30 min) in a hot environment, Active heating(60 min) in a hot environment, and Active heating (60 min) at room temperature), aiming to reach a core temperature of 38.5°C during a 60-minute period.

Part II focused on cooling the body to a pre-exercise baseline core temperature. Cooling strategies consisted of: 1) Cool vest (18°C) with 500 mL (16 fl oz) ice water consumption, 2) Damp neck towel (24°C) combined with arm (i.e. hand, forearm and half of upper arm) cool water immersion (15°C) and 500 mL (16 fl oz) ice water consumption 3) Combination of cool vest (18°C), damp neck towel (24°C) with arm cool water immersion (15°C), and 500 mL (16 fl oz) ice water consumption or 4) A control with participant sitting in a thermoneutral room (20°C air temperature) without any additional cooling intervention. Thermoneutral water was consumed ad libitum for all interventions in addition to the 500 mL (16 fl oz) ice water consumption for experimental trials (#1-3).

Study Timeline

• Study Start: 2020-09-14
• Primary Completion: 2020-10-23
• Study Completion: 2020-10-23
• Status Verified: 2025-03
• Study First Submitted: 2025-03-05
• Study First Submitted QC: 2025-03-07
• Last Update Submitted: 2025-03-07
• Study First Posted: 2025-03-13
• Last Update Posted: 2025-03-13

Recruitment & Eligibility

• Status: COMPLETED
• Sex: Male
• Target Recruitment: 10

Inclusion Criteria

• self-reported healthy
• non-smoking
• uninjured
• active (training five to ten hours per week)

Exclusion Criteria

• Participants were screened for fitness using the Physical Activity Readiness Questionnaire (PAR-Q): scoring one or more items as a yes.
• Contraindications to use a body core temperature sensor capsule.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SEQUENTIAL

Primary Outcome Measures

Name	Time	Method
Body core temperature	During 60 minute of heating intervention, followed by 60 minutes of cooling intervention.	A portable telemetry system (E-Celsius, BodyCAP, Hérouville Saint-Clair, France) for temperature sensor capsule, with an accuracy of +/- 0.2°C, was used to measure body core temperature.

Secondary Outcome Measures

Name	Time	Method
Skin temperature	During 60 minute of heating intervention, followed by 60 minutes of cooling intervention.	Wireless temperature sensors (iButton DS1+2L, Dallas Semiconductor Corp, USA), with an accuracy of ± 0.5°C and a resolution of 0.0625°C, were used to measure Tsk at 20-second intervals. Sensors at four locations (neck, right shoulder, and right shin with all 0.28 weighted coefficient, and left hand with a coefficient of 0.16 to calculate weighted Tsk outcome) as suggested per ISO protocol, held in place at the skin using Opsite transparent film (Opsite Flexigrid, Smith \& Nephew Medical Limited, Hull, England).
Heart rate	During 60 minute of heating intervention, followed by 60 minutes of cooling intervention.	Participants wore an elastic chest strap device (Bioharness-3, Zephyr Technology, Annapolis, MD, USA), measuring HR in beats per minute (bpm) at 1-second intervals.

Trial Locations

Locations (1)

Community Services Building; 🇺🇸 Tempe, Arizona, United States