How Much Water Should You Drink on a 5-Hour Walk in Warm Weather?

Staying hydrated is crucial for a safe and enjoyable walk, especially in warm weather. As your body works harder to navigate terrain and regulate temperature, it loses water through sweat and breathing. Proper hydration helps maintain energy, focus, and muscle function, preventing dehydration and heat-related illnesses.

Why Hydration Matters

Water regulates body temperature, supports muscles and joints, and sustains energy. Even mild dehydration can impair performance, cause headaches, and reduce focus. In hot conditions, fluid loss increases, making pre-planned hydration essential.

How Much Water Should You Drink?

A general guideline is 500 millilitres per hour, equating to 2.5 litres over a five-hour walk. However, this amount should be adjusted based on several factors. If your walk includes steep climbs or you are carrying a heavy pack, you may need closer to 750 millilitres per hour. In extremely hot and humid conditions, your intake may need to increase to 1 litre per hour. Some individuals sweat more than others, so if you tend to sweat heavily, consider carrying extra water or electrolyte drinks. Clothing also plays a role—moisture-wicking materials help reduce sweat loss, while heavy or non-breathable gear may cause you to lose more fluids.

Planning Your Water Supply

For a five-hour walk, it is advisable to carry at least 3 litres of water to account for any contingencies. Hydration bladders, such as CamelBaks, offer a convenient way to sip water regularly, though bottles work just as well if preferred.

Tips for Staying Hydrated

Drinking at regular intervals is important—sipping water every 15 to 20 minutes is better than waiting until you feel thirsty. Checking the color of your urine can provide insight into your hydration levels; pale yellow indicates good hydration, whereas dark yellow suggests you need more water. Since sweat contains essential minerals like sodium, potassium, and magnesium, replenishing electrolytes is important. This can be done through electrolyte tablets, sports drinks, or snacks like salted nuts. If your water supply is running low, taking small sips instead of large gulps and staying in shaded areas can help conserve fluids.

Water Sources on the Trail

If your route includes natural water sources such as streams or lakes, bringing a portable filter or purification tablets can reduce the amount of water you need to carry. However, it is essential to research the reliability and safety of these sources before setting out.

Signs of Dehydration & Overhydration

Recognizing dehydration early can prevent serious complications. Symptoms include dry mouth, headache, dizziness, fatigue, and reduced urine output. If these occur, stop in a shaded area, drink water, and rest before continuing. Overhydration, or hyponatremia, can happen when drinking excessive amounts of water without replacing lost electrolytes. Symptoms include nausea, confusion, and swelling in the hands or feet. Balancing water intake with electrolyte replenishment is key to avoiding this condition.

By planning ahead and staying mindful of hydration, you can ensure a safer, more enjoyable walking experience.