Two isothermal challenges yield comparable physiological and subjective responses.

Area of Science:

• Environmental Physiology
• Human Thermal Comfort
• Protective Clothing Systems

Background:

• Ventilated vests aim to reduce thermal stress through enhanced cooling.
• Understanding the impact of ventilated vests on physiological responses is crucial for occupational and athletic safety.

Purpose of the Study:

• To determine if wearing a ventilated vest results in equal thermal stress compared to a no-vest condition with similar dry thermal resistance.
• To investigate the effect of local ventilation on physiological and subjective responses during exercise in a hot-dry environment.

Main Methods:

• Nine healthy males performed treadmill walking (7 km/h) for 45 minutes in a hot-dry climate (34°C, 20% RH).
• Participants completed the trial with and without a ventilated vest.
• Continuous monitoring of gastrointestinal temperature (Tgi), heart rate (HR), and skin temperature (Tsk) was performed. Local sweat rate (LSR) and subjective ratings were also assessed.

Main Results:

• No significant differences were found in final Tgi, HR, or mean Tsk between the vest and no-vest conditions.
• Scapula skin temperature under the vest showed a trend towards being lower than without the vest.
• Local sweat rate on external locations and subjective responses did not differ between the two conditions.

Conclusions:

• Ventilated vests and non-ventilated systems with similar thermal resistance yield comparable thermal stress during exercise in hot-dry environments.
• Local ventilation provided by the vest did not influence sweating rates on body areas outside the vest.