This project investigates the effectiveness of pre-exercise active cooling using a temperature-controlled cooling vest in reducing heat-related physiological strain during endurance-type aerobic exercise in non-regularly trained ("weekend") athletes under hot and humid environmental conditions. Because these individuals often lack sufficient heat-acclimation training, they are at increased risk of excessive thermal stress, cardiovascular overload, and heat-related disorders during prolonged exercise.

Using a controlled laboratory design, participants will perform moderate-intensity endurance exercise in a simulated hot environment, with or without pre-cooling intervention. Peripheral circulation and thermoregulatory responses will be assessed through laser Doppler flowmetry based skin blood-flow analysis and infrared thermography, alongside heart rate and perceived exertion measures.

The study aims to clarify how active pre-cooling influences vascular regulation, sympathetic activity, skin temperature distribution, and exercise tolerance, and to evaluate its potential as a practical, non-fatiguing alternative to heat-acclimation training. The findings are expected to provide evidence-based guidance for reducing heat strain and improving exercise safety and comfort in recreational endurance athletes exercising in hot climates.

The primary aim of this study is to investigate the effects of pre-exercise active cooling using a temperature-controlled vest on peripheral vascular regulation mechanisms in non-regular endurance exercisers under hot environmental conditions. Specifically, this study seeks to quantify how pre-cooling modulates skin blood-flow dynamics, sympathetic nervous system activity, endothelial function, and myogenic vascular control, as assessed through frequency-domain analysis of laser Doppler flowmetry signals, before and after endurance-type aerobic exercise. By characterizing these microcirculatory responses alongside changes in skin-surface temperature measured via infrared thermography, the study aims to elucidate the physiological pathways through which active pre-cooling attenuates thermal strain and cardiovascular load during exercise in the heat.

Inclusion Criteria:

• Age 20-50 years.
• In the past 6 months, endurance exercise less than three times per week, 40-60 min each session.
• No cardiovascular, metabolic (e.g., diabetes), or neurological disorders, and no diseases affecting vascular regulation.
• No medication affecting vascular tone within the last 3 months.
• No major musculoskeletal injuries or disorders affecting performance within the last 3 months.

Exclusion Criteria:

• • Diabetes, hypertension, or peripheral vascular disease.

  • Long-term work in hot environments.
  • BMI > 30 kg/m², smoking, or heavy alcohol use.
  • Allergic reactions triggered by heat or cold (e.g., hives).