Oral Rehydration Improved Exercise Performance and Decreased Core Temperature and Heartrate Compared With Intravenous...

Area of Science:

• Exercise Physiology
• Sports Science
• Environmental Physiology

Background:

• Understanding hydration strategies is crucial for optimizing athletic performance and physiological responses during exercise in heat.
• Comparing oral versus intravenous (IV) rehydration methods provides insights into their respective efficacies.

Purpose of the Study:

• To investigate the impact of oral versus IV rehydration on exercise performance and physiological markers in a hot environment.
• To determine if oral rehydration leads to superior outcomes compared to IV rehydration during strenuous activity.

Main Methods:

• A randomized, cross-over study design was employed with recreational male athletes.
• Participants completed 90 minutes of cycling at 55% VO2peak followed by a 12-km time trial in a controlled hot environment (34.9°C).
• Rehydration was administered orally (25ml water every 5 min) or intravenously (25ml isotonic saline every 5 min).

Main Results:

• No significant differences in hydration status (urine specific gravity, body mass loss) were observed between oral and IV rehydration.
• Participants reported higher thirst levels and experienced significantly greater increases in rectal temperature (ΔTrec) with IV rehydration.
• The 12-km time trial performance was significantly faster with oral rehydration compared to IV rehydration.

Conclusions:

• Oral rehydration significantly enhances exercise performance and reduces core body temperature compared to IV rehydration in the heat.
• These findings suggest that oral rehydration may offer greater physiological and performance benefits for athletes exercising in hot conditions.