Clinical trial NCT06874023: Study to Warm Up and Cool Down Recreationally Active Males Using Different Protocols.
Official title: Warm Up and Cool Down Study: Various Combined Active and Passive Isothermic Heating Protocols, Followed by Different Cooling Protocols, to Increase and Lower Body Core Temperature.
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Heat Acclimation and Thermotolerance
Keywords: Heat
Adaptation
Passive heating
Lead sponsor: Arizona State University
Sponsor class: OTHER
First posted: 2025-03-13
Enrollment: 10
Sex: MALE
Minimum age (years): 18
Maximum age (years): 30
Standard ages: ADULT
Accepts healthy volunteers: no
Allocation: NA
Intervention model: SEQUENTIAL
Intervention model description: Participants performed 4 arms in non-random order (i.e. passive heating, exercise in the heat + passive heating, exercise in the heat, exercise at room temperature), followed by randomized cooling interventions (i.e. a cool slush and one of the three cooling treatments: 1) cool vest, 2) lower arm cool water immersion with cold towel in the neck, 3) combination of 1+2) or heaving no cooling intervention at room temperature with thermoneutral water only).
Primary purpose: OTHER

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).

Eligibility criteria: 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.

Primary outcomes:
measure: Body core temperature
timeFrame: During 60 minute of heating intervention, followed by 60 minutes of cooling intervention.
Secondary outcomes:
measure: Skin temperature
timeFrame: During 60 minute of heating intervention, followed by 60 minutes of cooling intervention.
measure: Heart rate
timeFrame: During 60 minute of heating intervention, followed by 60 minutes of cooling intervention.
Other outcomes:
measure: Sweat rate
timeFrame: Covering the 60 min of heating and 60 min of cooling resulting in an average sweat rate per hour.
measure: Urine specific gravity
timeFrame: Pre (within 30 min before heating) and post heating (within 5 min after finishing heating) and cooling interventions (within 5 min after finishing cooling).
measure: Environmental temperature
timeFrame: Continuous measurements during the 60 minute heating intervention, followed by the total duration of cooling to baseline intervention for a maximum of 60 minutes.
measure: Relative humidity
timeFrame: Continuous measurements during the 60 minute heating intervention, followed by the total duration of cooling to baseline intervention for a maximum of 60 minutes.
Locations:
city: Tempe
country: United States
facility: Community Services Building
state: Arizona
Study officials:
References: