Intravenous versus oral rehydration in athletes

Area of Science:

• Sports Medicine
• Exercise Physiology
• Human Performance

Background:

• Athletes often use intravenous (IV) fluids for rehydration, believing dehydration is key to heat illness.
• Voluntary IV fluid use for rehydration in healthy athletes is now banned by the World Anti-Doping Agency.
• The appeal of IV rehydration persists despite regulatory changes, necessitating a risk-benefit analysis.

Purpose of the Study:

• To evaluate the benefits and risks of intravenous (IV) fluid rehydration versus oral rehydration in athletes.
• To determine if the advantages of IV rehydration outweigh its potential drawbacks, especially after the WADA ban.

Main Methods:

• Review of existing studies comparing IV and oral rehydration in athletes.
• Analysis of hydration status markers, cardiovascular function, thermoregulation, and exercise performance.
• Consideration of physiological mechanisms, including oropharyngeal stimulation.

Main Results:

• IV rehydration leads to more rapid fluid uptake but offers transient benefits with minor differences in hydration markers compared to oral rehydration.
• Studies show mixed results on IV fluid's impact on cardiovascular function and thermoregulation, with some favoring oral fluids.
• Exercise performance improvements are not consistently greater with either IV or oral rehydration.

Conclusions:

• The definitive benefits of IV rehydration over oral rehydration for athletes remain unclear due to limited and varied research.
• A significant limitation of IV rehydration is the absence of oropharyngeal stimulation, affecting thirst and hormonal responses.
• Further research is essential to establish the comparative efficacy and safety of oral versus IV rehydration strategies for athletes.