Mechanisms Underlying Hypoxic, Heat and Cross-tolerance Adaptation in Women
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: Heat acclimation and exercise training, Thermo-neutral exercise training group.
- Who it may be relevant to
- Registry conditions: Heat Exposure, Exercise Training. Basic parameters: 18 years — 35 years · Female.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Slovenia
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
Unsure about the terms? Read our patient guide →
Official title
Investigating the Effects of a 10-day Heat Acclimation and Exercise Intervention on Physiological Adaptations and Cross-tolerance in Women
Overview
This study will consist of a parallel-groups design, with 30 healthy active female participants randomly assigned to either an experimental heat acclimation and exercise intervention, or a thermo-neutral exercise intervention control group. Interventions will be 10 days in duration, and consist of daily 60-minute exercise bouts under the appropriate environmental condition. Before and after each intervention, various tests will be conducted to establish exercise capacity under various environmental conditions, as well as underlying mechanisms of physiological adaptation induced by each intervention.
Detailed description
Most research on how the human body responds to different environmental conditions has primarily focused on men, leaving a gap in our understanding of how women adapt to these conditions. Heat exposure in particular is known to affect the well-being and performance of humans, as well as induce chronic adaptations through an acclimation/acclimatization process, which helps the body to better regulate core temperature. Moreover, contemporary research is beginning to explore the 'cross-tolerance' phenomenon; the notion that exposure (and acclimation/acclimatization) to one environmental stressor may affect the responses to another. In particular, both heat and hypoxia are known to activate common acclimatization pathways, with pulmonary, cardiovascular, hematological and muscular adaptations occurring to facilitate both oxygen transport and core body temperature regulation. In line with this background, the primary aim of this study is to investigate the effects of a heat acclimation and exercise intervention, relative to a thermo-neutral exercise control intervention, on exercise tolerance under various environmental conditions (heat, hypoxia, neutral) in healthy, active women. The secondary aim is to establish mechanisms of adaptation, by exploring the intervention-induced changes in pulmonary, cardiovascular, hematological and muscular factors, through various tests conducted at rest and during exercise.
To address these aims, 30 healthy active female participants, aged between 18 and 35 years, will be randomized to either an experimental (heat acclimation and exercise training) or control (thermo-neutral exercise training) group. The experimental group will complete a 10-day heat acclimation training intervention, exercising for 60 minutes per day in a climactic chamber set to 35°C and 50% relative humidity. The control group will complete a similar exercise intervention, but under thermo-neutral conditions (23°C and 50% relative humidity). Before and after the intervention period, both groups will complete a wide variety of tests, including exercise capacity measurements under each environmental condition (heat \[35°C\], hypoxia \[Fraction of inspired oxygen = 0.135\], neutral \[23°C, FiO2 = 0.209\]), body composition assessments, lung function testing, hemoglobin mass and blood volume quantification, skeletal muscle mitochondrial function and vascular responsiveness assessment, and venous blood sampling for a variety of sex hormone-, redox balance-, hematopoietic-, heat shock protein-, hypoxia-inducible factor- and genetic-related markers.
Interventions
- Other Heat acclimation and exercise training
10-day intervention consisting of daily 60-min exercise sessions aimed to induce increases in core body temperature, conducted in a climactic chamber set to 35°C and 50% relative humidity. - Other Thermo-neutral exercise training group
10-day intervention consisting of daily 60-min exercise sessions conducted in a climactic chamber set to 23°C and 50% relative humidity.
Primary outcome measures
- Exercise capacity under thermo-neutral normoxic conditions [Time frame: Measured once before (pre) and once up to 1 week after (post) the intervention period]
- Exercise capacity under hot normoxic conditions [Time frame: Measured once before (pre) and once up to 1 week after (post) the intervention period]
- Exercise capacity under thermo-neutral hypoxic conditions [Time frame: Measured once before (pre) and once up to 1 week after (post) the intervention period]
Secondary outcome measures (12)
- Core body temperature regulation during exercise [Time frame: Measured once before (pre) and once up to 1 week after (post) the intervention period]
- Skin temperature regulation during exercise [Time frame: Measured once before (pre) and once up to 1 week after (post) the intervention period]
- Sweat rates during exercise [Time frame: Measured once before (pre) and once up to 1 week after (post) the intervention period]
- Hemo-dynamic activity during exercise [Time frame: Measured once before (pre) and once up to 1 week after (post) the intervention period]
- Pulmonary ventilation during exercise [Time frame: Measured once before (pre) and once up to 1 week after (post) the intervention period]
- Gas exchange during exercise [Time frame: Measured once before (pre) and once up to 1 week after (post) the intervention period]
- Muscle oxygenation during exercise [Time frame: Measured once before (pre) and once up to 1 week after (post) the intervention period]
- Brain oxygenation during exercise [Time frame: Measured once before (pre) and once up to 1 week after (post) the intervention period]
- Pulse oxygen saturation during exercise [Time frame: Measured once before (pre) and once up to 1 week after (post) the intervention period]
- Body composition [Time frame: Measured once before (pre) and once up to 1 week after (post) the intervention period]
- Lung function [Time frame: Measured once before (pre) and once up to 1 week after (post) the intervention period]
- Hemoglobin mass [Time frame: Measured once before (pre) and once up to 1 week after (post) the intervention period]
Eligibility criteria
Inclusion criteria
- Age: 18 - 35 years
- Body mass index: 18.5 - 25.0 kg/m\^2
- Regular physical activity (at least 30 minutes of moderate-intensity activity, three times per week)
Exclusion criteria
- Habitual smoker within the past 5 years
- History of metabolic disorders or any medications deemed to pose an undue risk or introduce bias in any outcome measures
- Exposure to altitude > 2000 m above sea level within four weeks of scheduled participation
- Permanent residence at altitude > 1000 m above sea level
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: Yes
Study design
- Allocation
- Randomized
- Model
- Parallel assignment
- Masking
- Single blind
- Primary purpose
- Basic science
Study locations
Slovenia · 2 centers
- Jozef Stefan Institute — Ljubljana
- University of Ljubljana — Ljubljana
Identifiers
NCT: NCT06575985 · FemAdapt_HEAT · J5-50180