For ultra runners, hydration is not just about drinking water—it’s about maintaining endurance, optimising performance, and ensuring safety over kilometres of challenging terrain. The right hydration strategy can mean the difference between a strong finish and hitting the dreaded wall. Let’s explore the best hydration strategies for ultra-running and how collapsible bottles and reservoirs can change the game for long-distance athletes.

1. Carry the Right Hydration System

Hydration packs, collapsible bottles, and reservoirs all have their place in an ultra runner’s toolkit. The key is choosing the right combination based on distance, aid station availability, and personal preference.

Collapsible Soft Flasks: Perfect for quick sips on the go, Soft Flasks fit easily into running vests and shrink as you drink, reducing sloshing and bulk.

Hydration Reservoirs: Ideal for longer stretches between aid stations, reservoirs like the HydraPak Velocity™ provide hands-free drinking via a tube, allowing runners to sip without breaking stride.

Handheld Bottles: Some ultra runners prefer handheld bottles like the Tempo Pro for accessibility and ease of refilling, especially in shorter or well-supported races.

2. Plan Your Fluid Intake

A general rule is to drink 500 - 800 ml of fluid per hour during an ultra. However, individual needs vary based on sweat rate, weather, and race conditions. A collapsible hydration system allows efficient fluid management without unnecessary bulk or weight.

Before the Run: Preload hydration by drinking at least 500 - 800 ml of water with electrolytes an hour before starting.

During the Run: Sip small amounts regularly rather than chugging large amounts at once. Hydration reservoirs and Soft Flasks make this easier by providing easy access.

After the Run: Rehydrate with a mix of water and electrolyte drinks to replace lost minerals and prevent dehydration-related fatigue.

3. Balance Water and Electrolytes

Overhydration can be just as dangerous as dehydration. Consuming only water without replenishing electrolytes (sodium, potassium, magnesium) can lead to hyponatremia, which impairs performance and can be life-threatening.

Use Electrolyte Mixes: Many ultra runners add electrolyte powders or tablets to their SoftFlasks or reservoirs to maintain balance.

Alternate Between Water and Electrolyte Drinks: Having one collapsible bottle for water and another for an electrolyte mix can help maintain the right balance.

Eat Salty Snacks: Solid foods like pretzels, nuts, or energy chews can also contribute to electrolyte replenishment.

4. Refill Smart and Stay Efficient

Collapsible bottles and reservoirs make refilling at aid stations quicker and more efficient. Unlike rigid bottles, they fold down when empty, saving space in your running vest. When stopping to refill:

• Prioritise speed by pre-mixing electrolyte powders in a SoftFlask.

• Use high-flow valves for quick hydration access.

• Opt for bottles like the UltraFlask+ with built-in filtration if running unsupported in remote areas.

5. Train with Your Hydration Setup

Don’t wait until race day to test your hydration system. Practice with your collapsible bottles and reservoirs during training runs to determine what works best for you. Consider:

• How easy it is to drink while moving.

• Whether the hydration system causes discomfort or bouncing.

• How quickly you can refill and manage fluids at aid stations.

Final Thoughts

Ultra running demands a well-thought-out hydration strategy, and collapsible bottles and reservoirs provide a lightweight, flexible, and efficient way to stay fueled. By choosing the right system, maintaining fluid-electrolyte balance, and practising refuelling techniques, you can ensure peak performance and endurance on race day.

Stay hydrated, run strong, and let HydraPak help you go the distance!