Moderate exercise effects on orthostatic intolerance while wearing protective clothing

Area of Science:

• Physiology
• Human Performance
• Protective Clothing Research

Background:

• Protective clothing can negatively impact physical performance and cause heat stress.
• Understanding the physiological effects of protective clothing during exercise is crucial for operational safety.

Purpose of the Study:

• To investigate the effects of moderate exercise while wearing protective clothing on orthostatic tolerance in healthy individuals.
• To assess physiological responses, including cardiovascular and thermoregulatory changes, during and after exercise in protective gear.

Main Methods:

• Eight healthy subjects performed a 60-minute moderate treadmill exercise followed by a 45-minute head-up tilt test.
• Exercise was conducted under two conditions: comfortable (control) and wearing protective clothing (PRO), in a randomized order.

Main Results:

• Exercise in protective clothing (PRO) led to increased dehydration, heart rate, rectal temperature, and decreased plasma volume compared to control (CON).
• Orthostatic tolerance was significantly reduced in the PRO trial (23.7 min) versus CON (40.7 min).
• PRO condition showed decreased blood pressure, reduced RR interval, and diminished spontaneous baroreflex sensitivity in both supine and standing positions.

Conclusions:

• Wearing protective clothing during exercise substantially reduces orthostatic tolerance.
• The decreased tolerance is attributed to an inability to maintain blood pressure due to conflicting physiological demands (vasoconstriction vs. thermoregulation) and impaired baroreflex sensitivity.
• These findings highlight the physiological challenges and risks associated with exercising in protective gear.