Drinking to thirst versus drinking ad libitum during road cycling

Area of Science:

• Sports Science
• Exercise Physiology
• Hydration Research

Background:

• Thirst sensation differs from ad libitum drinking behavior in athletes.
• Existing rehydration recommendations vary, lacking systematic comparison between drinking to thirst and ad libitum strategies.

Purpose of the Study:

• To compare physiological and perceptual outcomes between trained cyclists employing drinking to thirst (D(TT)) versus ad libitum drinking (D(AL)).

Main Methods:

• A cohort study involving 24 ultraendurance cyclists (12 D(TT), 12 D(AL)) during a 164 km road cycling event in heat (36.1°C).
• Measurements included body mass, urinary hydration indices, and food/fluid intake before, during, and after the event.

Main Results:

• No significant differences were observed between D(TT) and D(AL) groups in exercise time, hydration indices, body mass change, fluid intake during exercise, energy intake, or perceptual responses.
• A significant difference was found in total fluid intake on recovery day +1, with the D(AL) group consuming more.

Conclusions:

• Drinking to thirst and drinking ad libitum yield comparable physiological and perceptual results during endurance cycling events.
• Specific "drink to thirst" instructions may be unnecessary; ad libitum drinking allows athletes to concentrate on training and competition.