Staying hydrated is crucial for enjoying a safe and successful hiking experience. Yet, it’s surprising how many people head out for a walk or hike without considering their water and hydration needs. While it may be less of a concern in urban settings, venturing into the bush, even for a short stroll, requires preparation to ensure you return safely.
The Risks of Insufficient Hydration
It may sound dramatic, but many incidents show how quickly minor issues can escalate during short walks in unfamiliar bush settings. Lack of water contributes to fatigue, poor decision-making, and increased risk if you become delayed, lost, or injured.
Before setting off on any hike that takes you away from immediate access to your vehicle or reliable water sources, carry water with you. How much you need depends on distance, terrain, temperature, pace, and your individual sweat rate. Drink regularly throughout the hike rather than waiting until you feel very thirsty. Small, frequent drinks while walking or larger drinks at rest breaks are both effective, as long as you are replacing fluid losses over time.
Understanding Your Body’s Needs
The adult human body is made up of around 60 percent water, and physical activity increases fluid loss through sweating and breathing. As these losses accumulate, both physical performance and mental clarity begin to decline.
Thirst is a useful signal, but it often appears after fluid loss has already begun, particularly during exercise or in warm conditions. Because the body cannot produce water, it is important to carry an adequate supply and replace fluids regularly. Electrolytes may also be needed on longer or more strenuous hikes to replace salts lost through sweat.
How Much Water Should You Drink?
The amount of water you need depends on several factors, including:
- Type of activity
- Intensity level
- Duration of the hike
- Weather conditions
- Age
- Individual perspiration rate and body type
As a general guideline, aim for about half a litre of water per hour of moderate activity in moderate temperatures. Increase your intake if the weather is hotter or if the activity is more intense.
For example, on a moderate 4-hour hike, you should aim to drink around two litres of water. A good indicator of hydration is the colour of your urine; light yellow (straw colour) suggests you’re adequately hydrated. If you’re not needing to urinate, it’s likely you’re losing fluids faster than you’re replacing them, so be sure to drink more.
Pre-Hydration and Rehydration Strategies
Pre-hydrate: It’s wise to hydrate before your hike. A general recommendation is to drink about 450ml of water about two hours prior to setting out. Depending on how far you need to drive, I typically drink around 250ml before leaving home and another 250ml before starting the hike.
Rehydrate: After your hike, replenishing your fluids helps restore normal hydration levels and aids in recovery. Aim to drink several cups of water after finishing, taking it slowly—about half a cup every 15 minutes is a good pace. Including electrolytes in your post-hike hydration can further support recovery.
The Role of Electrolytes
Electrolytes—essential minerals like sodium, potassium, calcium, and magnesium—are vital for many bodily functions. When you sweat, you lose electrolytes, which can impact your performance if not replaced.
For hikes lasting an hour or less, electrolyte loss typically isn’t an issue. However, for longer treks, replacing lost electrolytes becomes crucial. Focus on sodium and potassium, but don’t overlook calcium and magnesium. Electrolyte replacement drinks are convenient; look for powders and tablets that can be mixed with water before you head out or during your hike. Always follow the directions for mixing and consumption.
Hydration: The Rule of Threes
The Rule of Threes is a widely used survival guideline to help prioritise threats in an emergency. It outlines approximate timeframes, not guarantees:
- About 3 minutes without air, or in icy water
- About 3 hours without adequate shelter in harsh conditions
- About 3 days without water
- About 3 weeks without food
While air is usually available, and food shortages are uncomfortable rather than immediately dangerous, lack of water becomes critical much sooner. In hot or exposed conditions, dehydration can become life-threatening within a short period, while cooler conditions may allow longer survival.
These are general estimates. Actual survival time varies widely depending on weather, terrain, clothing, activity level, health, and available resources. The purpose of the rule is to help identify and address the most immediate threat first, not to suggest fixed limits.
Drink Regularly
Aim to drink regularly to avoid dehydration, but be mindful not to overhydrate. Maintaining a balance of fluids and electrolytes helps reduce muscle soreness and combat the effects of heat and elevation. Personally, I take a drink every 20 minutes during hikes and remind my kids to do the same. For longer trips, I also carry powdered electrolyte mix to prepare a litre of hydration for the journey to camp (for overnight hikes) or post-hike recovery (for day hikes). It’s remarkable how much better you can feel with proper hydration.
Important Reminders
- Avoid drinking untreated water from streams, lakes, or other natural sources unless it has been properly treated.
- Rehydrate gradually after a long hike. Cool or cold fluids are safe to drink and can help with cooling and recovery, especially in warm conditions.
- Avoid alcohol during or immediately after hiking, as it can impair judgement and increase fluid loss.
Running out of water presents a far more immediate risk than running out of food. Careful planning, carrying enough water, and drinking regularly are essential for staying safe on the trail.
By staying informed and prepared, you can enjoy your hiking adventures while ensuring your health and safety. Stay hydrated and happy hiking!
Related articles
How to Spot and Treat Mild Dehydration
How to spot and treat heat exhaustion
Overhydration and Hyponatremia
Tips for avoiding heatstroke when hiking
Yeah. I do t think they would be a fun three days though. Would all depend on the temperature and your workload. I’d suggest days without water would be drastically reduced in hot weather.