Planned drinking vs drinking to thirst for ultra-endurance💧
A case of one vs the other? Or a combined approach?
Hydration Strategies in Ultra-Endurance Running: A Narrative Review of Programmed Versus Thirst-Driven Approaches
Study Details
DRINKING TO THIRST (TDFI) 🧠
🧠 Drinking to thirst uses internal cues to regulate intake, allowing athletes to respond naturally to rising plasma osmolality and real-time physiological demand
🏔️ Field studies show TDFI is safe, practical and effective for most experienced ultra-runners, with no increased risk of hyponatraemia or performance decline
PROGRAMMED DRINKING (PFI) 📊
🥵 PFI prescribes fluid intake based on sweat-rate testing and planned volumes, often aiming to keep body mass loss below 2%
🔬 Lab studies show PFI preserves plasma volume and lowers cardiovascular strain, but real-world ultras make strict plans difficult to execute
This review of 6 studies (over 900 athletes) examined how PFI compares with TDFI for…
💧 Hydration
🏆 Performance
✅ Safety
…in ultra-endurance running 🏃♂️
It aimed to evaluate which strategy works best in real-world ultra conditions where terrain, heat, GI issues and logistics heavily influence hydration needs 🌍
Here are the key findings ⬇️
Key Findings
💧 TDFI is safe and effective for most ultra-runners, with no increased risk of hyponatraemia even when body mass drops 2–5%
🏋️♂️ PFI shows physiological benefits in controlled lab conditions, but these rarely transfer to real-world ultra environments
⏳ Performance was not related to body-mass change, and many top finishers lost more than 2–4% without impairment
🚰 Overhydration risk is greater when following rigid PFI plans, particularly among slower athletes with more aid-station exposure
🤢 GI distress is more common when PFI forces athletes to drink beyond their gut tolerance during long events
🔄 A hybrid strategy is likely optimal, combining sweat-rate awareness with real-time thirst cues and environmental context
🏃♂️ Moderate dehydration (2–4%) does not impair performance in ultra-endurance events and is often a normal physiological response
Conclusion
A hybrid approach is definitely the best strategy IMO, where you can establish upper and lower limits of fluid intake and aim to drink to thirst within those parameters 🥤
An example of “its not always one or the other” a combined approach can, and should, be implemented ✅
Reference
https://pubmed.ncbi.nlm.nih.gov/41305577/
Performance Nutrition Digest is powered by Healthspan Elite ⚡️
Healthspan Elite is a science-led sports nutrition range developed in collaboration with leading experts to support athletic performance, recovery, and health.
Use code: TCDIGEST25 for 25% off at https://www.healthspanelite.co.uk/ 💪