The Effect of Daily Brief Whole-body Heat Exposures on Heat Acclimation and Its Decay
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 26
- 试验地点
- 1
- 主要终点
- Dehydration (kg)
研究概览
简要总结
This study is the first to examine the effects of short passive heat exposure on heat acclimation (HA). Unlike traditional protocols requiring prolonged heat exposure, this study tests whether a daily 5-minute whole-body immersions at 45°C water repeated over two weeks can trigger adaptive responses, offering a potentially more accessible and time-efficient method for heat acclimation. This study aims to investigate whether brief, repeated passive heat exposure can induce HA in both female and male participants. It evaluates changes across physiological, biological, and psychological markers to determine the efficacy of this minimal-exposure protocol. It is hypothesized that such short, repeated immersions may be sufficient to elicit significant adaptive responses across key HA indicators.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Basic Science
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 35 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Healthy, non-obese males and females aged 18 to 35 years with a body mass index between 18.5 and 29.9 kg/m².
- •No participation in temperature manipulation programs (e.g., cold or heat acclimation) within the past three months.
- •No engagement in excessive formal exercise.
- •Female participants must have a regular menstrual cycle.
排除标准
- •Current smokers.
- •Fear of needles or blood.
- •Use of medications or supplements that could affect study outcomes.
- •History of neurological, cardiovascular, metabolic, or inflammatory diseases that could be aggravated by hot water exposure.
研究组 & 干预措施
Heat acclimation
干预措施: Heat acclimation (Other)
结局指标
主要结局
Dehydration (kg)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Dehydration (in kg) was assessed by calculating body mass loss (Tanita Body Composition Analyzer; USA) during heat exposure.
Heart rate (bpm)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Heart rate (in bpm) was recorded using a heart rate sensor with a chest strap (Polar, Finland).
Blood pressure (mmHg)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Systolic and diastolic blood pressure (in mmHg) was measured using with an automatic cuff monitor (Gentle+, Microlife, Switzerland).
Pulse pressure (mmHg)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Pulse pressure (in mmHg) was calculated by subtracting diastolic blood pressure from systolic blood pressure.
Rate of pressure production (AU)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Rate of pressure production (in AU) was calculated by multiplying heart rate , by systolic blood pressure.
Shivering/sweating (points)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
The shivering/sweating rate will be evaluated using 7-point scale. The rating of shivering/sweating range from 1 (heavily sweating) to 7 (vigorously shivering), with 4 being neutral.
Thermal comfort (points)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Thermal comfort will be evaluated using 4-point scale. The rating of thermal comfort range from 0 (neutral) to 3 (very uncomfortable).
Body temperature (°C)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Rectal temperature (in °C) was measured using a thermocouple (Rectal Probe, Ellab, Denmark) inserted to a depth of 12 cm past the anal sphincter, skin temperature (in °C) was measured with thermistors (Skin/Surface Probe, DM852, Ellab), and muscle temperature (in °C) was measured using a needle microprobe (MKA; Ellab).
Physiological strain index
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Physiological strain index (PSI) was used to indicate heat strain. PSI = 5 x (Tret - Tre0) x (39.5 - Tre0)\^-1+ 5 x (HRt - HR0) x (180 - HR0)\^-1, where rectal temperature (Tre) t and heart rate (HR) t are simultaneous measurements taken at the end of the heat exposure and Tre0 and HR0 are the initial measurements.
Oxygen consumption (mL/min/kg)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Oxygen consumption (in mL/min/kg) was measured using Cortex METALYZR® 3B, Leipcig, Germany).
Carbon dioxide output (mL/min/kg)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Carbon dioxide output (in mL/min/kg) was measured using Cortex METALYZR® 3B, Leipcig, Germany).
Carbon dioxide output (mL/min)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Carbon dioxide output (in mL/min) was measured using Cortex METALYZR® 3B, Leipcig, Germany).
Oxygen consumption (mL/min)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Oxygen consumption (in mL/min) was measured using Cortex METALYZR® 3B, Leipcig, Germany).
Respiratory quotient
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
The respiratory quotient was calculated by dividing the carbon dioxide output by the oxygen consumption. This ratio was used to assess substrate utilization. The values for fat is assumed as 0.7, for protein is assumed as 0.8 and for carbohydrate is assumed as 1.0.
Ventilation (L/min)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Ventilation (in L/min) was measured using Cortex METALYZR® 3B, Germany).
Tidal volume (L)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Tidal volume (in L) was measured using Cortex METALYZR® 3B, Germany).
Dehydration (kg)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Dehydration (in kg) was assessed by calculating body mass loss (Tanita Body Composition Analyzer; USA) during heat exposure.
Carbon dioxide output (mL/min)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Carbon dioxide output (in mL/min) was measured using Cortex METALYZR® 3B, Leipcig, Germany).
Heart rate (bpm)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Heart rate (in bpm) was recorded using a heart rate sensor with a chest strap (Polar, Finland).
Rate of pressure production (AU)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Rate of pressure production (in AU) was calculated by multiplying heart rate , by systolic blood pressure.
Blood pressure (mmHg)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Systolic and diastolic blood pressure (in mmHg) was measured using with an automatic cuff monitor (Gentle+, Microlife, Switzerland).
Pulse pressure (mmHg)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Pulse pressure (in mmHg) was calculated by subtracting diastolic blood pressure from systolic blood pressure.
Shivering/sweating (points)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
The shivering/sweating rate will be evaluated using 7-point scale. The rating of shivering/sweating range from 1 (heavily sweating) to 7 (vigorously shivering), with 4 being neutral.
Thermal comfort (points)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Thermal comfort will be evaluated using 4-point scale. The rating of thermal comfort range from 0 (neutral) to 3 (very uncomfortable).
Body temperature (°C)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Rectal temperature (in °C) was measured using a thermocouple (Rectal Probe, Ellab, Denmark) inserted to a depth of 12 cm past the anal sphincter, skin temperature (in °C) was measured with thermistors (Skin/Surface Probe, DM852, Ellab), and muscle temperature (in °C) was measured using a needle microprobe (MKA; Ellab).
Physiological strain index
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Physiological strain index (PSI) was used to indicate heat strain. PSI = 5 x (Tret - Tre0) x (39.5 - Tre0)\^-1+ 5 x (HRt - HR0) x (180 - HR0)\^-1, where rectal temperature (Tre) t and heart rate (HR) t are simultaneous measurements taken at the end of the heat exposure and Tre0 and HR0 are the initial measurements.
Oxygen consumption (mL/min/kg)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Oxygen consumption (in mL/min/kg) was measured using Cortex METALYZR® 3B, Leipcig, Germany).
Carbon dioxide output (mL/min/kg)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Carbon dioxide output (in mL/min/kg) was measured using Cortex METALYZR® 3B, Leipcig, Germany).
Respiratory quotient
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
The respiratory quotient was calculated by dividing the carbon dioxide output by the oxygen consumption. This ratio was used to assess substrate utilization. The values for fat is assumed as 0.7, for protein is assumed as 0.8 and for carbohydrate is assumed as 1.0.
Oxygen consumption (mL/min)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Oxygen consumption (in mL/min) was measured using Cortex METALYZR® 3B, Leipcig, Germany).
Ventilation (L/min)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Ventilation (in L/min) was measured using Cortex METALYZR® 3B, Germany).
Tidal volume (L)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Tidal volume (in L) was measured using Cortex METALYZR® 3B, Germany).
Breathing frequency (t/min)
时间窗: From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).
Breathing frequency (t/min) was measured using Cortex METALYZR® 3B, Germany).
次要结局
- Body mass index (kg/m^2)(From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).)
- Prolactin (ng/mL)(From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).)
- 17beta-estradiol (pg/mL)(From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).)
- Height (cm)(During enrollment)
- Body mass and body composition (kg)(From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).)
- Body composition (%)(From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).)
- Maximal oxygen consumption (in mL/min/kg)(During enrollment)
- Progesterone (ng/mL)(From enrollment to the end of deacclimation (one month after the 14-day heat acclimation period).)