Acute physiological response to indoor cycling with and without hydration; case and self-control study

Area of Science:

• Exercise Physiology
• Sports Nutrition
• Human Performance

Background:

• Oral rehydration is crucial for maintaining physical capacity and hydration during exercise.
• Understanding the impact of different hydration strategies is vital for optimizing athletic performance.

Purpose of the Study:

• To evaluate the effectiveness of three hydration protocols (no liquids, plain water, sports drinks) on work capacity and physiological stress during indoor cycling (InC).
• To identify the most sensitive physiological variable reflecting hydration status during prolonged exercise.

Main Methods:

• A randomized, controlled study involving 14 middle-aged men performing 90-minute InC sessions.
• Three hydration protocols were tested: no liquids, plain water, and sports drinks (SD).
• Physiological responses (body temperature, heart rate, blood pressure) and work capacity were measured, with covariables including body composition and exercise intensity.

Main Results:

• No significant differences in work capacity were observed across the three hydration protocols.
• Subjects exhibited higher body temperature, heart rate, and mean blood pressure when no liquids were consumed compared to water or SD.
• Body temperature was identified as the most sensitive indicator of hydration status.

Conclusions:

• Liquid intake, whether plain water or sports drinks containing electrolytes, does not impact work capacity during 90 minutes of intense InC.
• Both plain water and sports drinks are equally effective for hydration during prolonged, high-intensity indoor cycling.
• Body temperature serves as the most sensitive physiological marker for assessing hydration status in athletes during strenuous exercise.