Developing a Hydration and Electrolyte Strategy is Part of the Efficiency Equation for Hiking, Climbing and Backpacking
My favorite activity is hiking long distances, especially in October along the dry sunny eastern slopes of the Cascade Mountains after the rainy season begins in Western Washington. It's an opportunity to extend summer and capture the sun's energy. There is a freedom of the hills on long hikes that affords an opportunity to refresh the mind and body and provide a break from the modern routine of office, digital and urban life. Distance hiking, backpacking and climbing is in several ways an exercise in efficiency. While efficiency is important, maintaining good hydration and electrolyte balance is essential. Developing an effective hydration and electrolyte strategy is part of the efficiency equation.
Although I had been hiking for many years, it was not until 2003, when I began training for Ironman triathlons, did I focus more intensely on the hydration and electrolyte needs of endurance events or activities. Yet moderate and long distance hiking, backpacking and climbing demands the same attention to hydration and electrolyte balance needs. What has been learned about hydration and electrolytes for Ironman triathlon training has been very helpful in developing hydration and electrolyte strategies for moderate and long distance hiking, backpacking and climbing.
What is the Function of Hydration?
Our body composition is 66% water. Fluid and electrolyte balance is a major function of homeostasis, which is our bodies ability to maintain its internal environment as it adjusts to challenges and stress. To the extent our bodies are able to adjust to these challenges the state of good health is maintained. Proper hydration is important for cellular metabolism, blood flow and therefore physical and athletic performance.
Warning Signs of Dehydration
If your are feeling thirsty, you are already somewhat dehydrated. The warning signs of dehydration include:
Many athletic event related cardiac arrests are related to electrolyte imbalance or severe dehydration or heat exhaustion (stroke). See Cardiopulmonary Resuscitation (CPR) is a Life Skill: Learn How to do it!
Fluid Intake Requirements for Hiking, Backpacking and Climbing
The best hydration strategy for hikers, backpackers and climbers is to maintain focus on staying fully hydrated beginning one week before your hike, climb or backpacking trip. Good hydration is especially important for the two to three days prior to your trip.
To determine how much water you should be consuming on a daily basis, divide your body weight by half. That is amount of water in ounces you should be consuming daily without exercise. Add another 8 to 16 ounces for every 60 minutes of strenuous exercise you do.
By way of comparison, Cyclists are recommended to drink 24oz of fluid each hour cycling for distance events. Runners are recommended to drink 16- 27oz of fluid each hour running for distance events.
Another measure of adequate fluid intake is body weight. Athletes are recommended to weigh themselves daily prior to training so they can become aware of decreases in body weight due to dehydration. Athletes who are down 1-2% in body weight can be assumed to be dehydrated.
Note, that too much fluid can cause GI distress. The speed at which a beverage travels from the stomach in to the small intestine (the gastric emptying rate) depends on the energy content (calories) and volume of the beverage consumed. A small concentration of carbohydrate will encourage rapid absorption, but too much carbohydrate will slow gastric emptying and can result in GI distress.
Hydration and Electrolyte Balance
Maintaining Hydration and Electrolyte Balance is critical to nerve and muscle function, and as such, is a key consideration for hikers and climbers hoping to achieve their optimum athletic performance. Electrolytes are molecules capable of conducting electrical impulses and include sodium (Na+), , potassium (K+), calcium (Ca2+), magnesium (Mg), and chloride (Cl). Muscle contraction is dependent upon the presence of electrolytes. Without sufficient levels of these key electrolytes, muscle weakness or severe muscle contractions may occur. See also Potassium Natural Food Sources for Optimum Health and Performance
Hyponatremia, a low concentration of sodium in the blood, has become more prevalent in ultra-endurance athletes. Adequate sodium balance is necessary for transmitting nerve impulses and proper muscle function, and even a slight depletion of this concentration can cause problems. Distance hikes or long challenging climbs that take place in hot, humid conditions, are conditions prime for hyponatremia to develop. During high intensity exercise, sodium is lost along with sweat. An athlete who only replaces the lost fluid with water may contribute to a decreased blood sodium concentration. Fluids with electrolytes are recommended for hikers and climbers during long outings. It's also advisable to carry salt pills on a long days of continuous physical activity. It's a good idea to take a salt pill (with water) at the start of specific muscle pain.
Hydration Needs of Hikers, Climbers and Backpackers in Hot, Humid, Windy or Cold Weather
Once the body starts to become dehydrated, it canít function at its full capacity and as normal metabolism becomes impaired, your health and physical performance is at risk. Dehydration risks increase during hot, humid, windy and cold weather. Dehydration risks also increase with significant elevation gain and prolonged explosure at higher elevations.
Cold Weather Hydration. Surprisingly, dehydration is also a winter hazard. Sweat may not pour from your brow the way it does in summer, but depending on your level of exertion and the dryness of the air, significant moisture loss occurs. Also, fluid intake normally drops because people don't crave cold drinks during the winter.
The onset of dehydration often times is the cause of hypothermia. Hypothermia is very possible during endurance training and competitions (like Marathons and Ironman Triathlons) conducted in the cold, as well as hiking, climbing and backpacking in the cold. A person can become hypothermic if the rate of heat production during exercise is exceeded by the rate of heat loss. Dehydration and then Hypothermia causes a lower cellular metabolic rate which further decreases body temperature. During hypothermia blood volume decreases due to inadequate fluid intake reducing central nervous system and key organ functions.
Mountaineers should be well aware that drinking plenty of fluids during cold weather is essential to maintain core body temperatures to safely tackle the mountains in winter.
Hot Weather Hydration. The debilitating effects of heat stress on the ability to perform prolonged strenuous exercise are well established. During exercise in a hot environment, a substantial rise in body core temperature is often linked with the onset of fatigue. Fluid replacement before and during prolonged exercise in the heat has been shown to be effective in reducing the elevation of body temperature and in extending endurance capacity.
Recent studies have show that ingestion of a cold drink before and during exercise in the heat reduced physiological strain (reduced heat accumulation) during exercise, leading to an improved endurance capacity. Exercise time was longer with the cold drink than with the warm drink, as the cold drink lowered heart rate, lowered skin and core temperature. Drinking cold drinks during exercise also reduced the need to sweat, resulting in a longer sweating capacity.
When exercising in hot weather, the combination of the external heat and the internal heat produced from the exercise, heat within the body can build causing Hyperthermia which is having a core body temperature that is too high. Maintaining good hydration can reduce the onset of Hyperthermia as good hydration enhances sweating which acts to cool core body temperatures.
Scientific data supports the position that caffeine reduces heat tolerance during exercise in a hot environment, via three physiological mechanisms. First, the diuretic effect of caffeine may exaggerate the declines that occur with plasma volume and stroke volume. Second, caffeine stimulates the sympathetic nervous system, and it may increase sweat rate. Third, caffeine increases resting metabolic rate in physically trained and sedentary individuals; this may increase heat storage and internal body temperature. These effects reduce heat tolerance (i.e., the exercise time to fatigue or exhaustion) by exacerbating dehydration and increasing body temperature. See How Caffeine Impacts Athletic Performance.
Humid Weather Hydration. In very humid weather, our sweat doesn’t evaporate as very well and we tend to sweat more with less cooling effect thereby loosing needed fluids to maintain good performance. Fatigue will begin to increase when fluids are not replaced and under extreme lack of fluid replacement heat exhaustion or stroke can occur.
Windy Caused Dehydration. Windy conditions whether hot or cold can sap moisture from your body even when standing still. Extra hydration is necessary during windy conditions.
Elevation and Elevation Gain. The amount of fluid intake needs can be greatly impacted by elevation and elevation gain. Trips with significant elevation gain are more strenuous and require greater fluid intake. Prolonged hiking and climbing at high elevations can also require greater fluid intake as faster breathing rhythms experienced at higher elevations (due to lower oxygen levels) are dehydrating.
Acclimate. When long distance hiking, climbing or backpacking tiips are planned in weather conditions very different from your regular environment, it is recommendedl to arrive at your trip destination ideally 4 days prior to the start of your hike, climb or backpacking, to enable the body to adjust to the different environment to enable your body reach a hydration balance consistent with this new environment.
Foods and Natural Sources of Electrolytes
A good natural source of electrolytes is from food. Fruit and vegetables, including canned or frozen vegetables like corn, carrots and green beans, are high in electrolytes, as are bread, milk, and fruit. Water with a small pinch of salt (1/3 tsp per liter), sugar (3-5 tsp/liter) and flour added to it will provide electrolytes and energy.
A teaspoon is approximately 5 grams (5000 mg) and for sodium chloride (table salt) about Ĺ of this is sodium (this is an approximation as a teaspoon measures volume and grams are a measure of mass and every item has a different mass but it is close enough). Most sport drinks sodium at contain ~ 50 mg / 100 ml (0.5 g / liter). So Ĺ tsp in 2 liters is about the correct amount.
Electrolyte content of some foods (note 100 g is about 3.5 oz)
It is a good strategy to be in electrolyte balance prior to your trip!
Consuming some of the foods listed above prior to your trip and including some of the above food in your trip provisions will help maintain electrolyte balance during your trip!<-- back to top
Articles on Hydration and Electrolytes for Endurance Events
Hydration and Electrolytes - Impact on Athletic Performance, Paul Bennett, Jr., Ph.D. on 1Vigor.com
Ultarunning Hydration, James Styler on 1Vigor.com