None listed
Conditions
Brief summary
The project aims to identify whether gut microbiota (bacteria) are either disrupted (dysbiotic) or resistant (resilient) to heat stress. The study will also explore how microbiota composition influences cognitive abilities, physical performance, and well-being during heat stress by analysing a range of biological (i.e. stool, blood, and urine) and non-biological (i.e. cognitive assessment and questionnaires, physical function and performance analysis) outcomes. We hypothesize that two days of simulated heat stress will negatively alter the intestinal microbiota composition in healthy adults, reducing diversity, increasing pro-inflammatory taxa, decreasing beneficial taxa, increasing intestinal permeability, and impairing cognitive, physical, and well-being outcomes.
Interventions
Treatment: Other (Hot Temperature Exposure). Participants will complete 2-days (cumulative) of simulated heat exposure (40°C air temperature and 40% relative humidity (RH) with minimal air flow (<0.3 m/sec)) within La Trobe University’s environmental chamber (Bundoora campus). Participants will undertake up to 5.75 hrs (‘workday’) of heat exposure per day while performing three 75 min blocks of physical activity. The first two 75 min blocks will comprise of treadmill walking at a moderate metabo
Treatment: Other (Hot Temperature Exposure). Participants will complete 2-days (cumulative) of simulated heat exposure (40°C air temperature and 40% relative humidity (RH) with minimal air flow (<0.3 m/sec)) within La Trobe University’s environmental chamber (Bundoora campus). Participants will undertake up to 5.75 hrs (‘workday’) of heat exposure per day while performing three 75 min blocks of physical activity. The first two 75 min blocks will comprise of treadmill walking at a moderate metabolic rate (~200 Watts/m2), with 60 min passive, seated recovery between sessions. The final 75 min block will consist of 30 min treadmill walking (~200 Watts/m2), followed by 45 min treadmill jogging/running at a heavy metabolic rate (~300 Watts/m2). Up to two participants will complete the exposure at one time. La Trobe researchers will supervise and monitor all sessions. To monitor safety of participants, researchers will assess 6–20-point rating of perceived exertion scale (RPE), 13-point thermal sensation scale, and the 5-point thermal discomfort scale before the start of the ‘workday’ and every 15 minutes during the workday (including recovery during and after the exercise). Core body temperature and heart rate will also be monitored throughout.
Sponsors
La Trobe University
Study design
Allocation
Non-randomised trial
Intervention model
Crossover
Primary purpose
Prevention
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to 39 Years
Healthy volunteers
Yes
Inclusion criteria
• Male and female adult aged 18–39 years • Non-smoker • No pre-existing medical conditions that may interfere with the study (e.g., cardiovascular, respiratory, or metabolic disorders) • Not on any medication that may interfere with thermoregulation, immune function, or inflammation (i.e. regular anti-inflammatory use) • Currently engaged in regular physical activity (2-3 times per week)
Exclusion criteria
• BMI >30kg/m2. • VO2max/peak below 35 ml/kg/min or above 60 ml/kg/min • Currently pregnant or breastfeeding • History of heat intolerance • Severe allergies to food or environmental factors • Diagnosed with gastrointestinal infections, diseases, or disorders • Consumption of known modifiers of gastrointestinal integrity, such as probiotics and antibiotics within the previous 3 months. • Consumption of nonsteroidal anti-inflammatory medications and/or stool-altering medications (e.g., laxatives, anti-diarrheal) within previous month.
Outcome results
None listed