Guide to Nutrition & Hydration | The Himalaya & High Altitude
NUTRITION & HYDRATION TIPS FOR HIGH ALTITUDE
– Marisa Michael, MSc, RDN, LD
Article
High Altitude Defined
As you go higher, the air is ‘thinner’. This means oxygen molecules are spread farther apart than at sea level. What does that mean for your body? Less oxygen is delivered to your tissues for each breath of air you inhale.
Why is this a Problem at High Altitude?
Less oxygen can decrease performance, especially if you haven’t had time to acclimate. If you’re only there for a few days, your body won’t have time to adapt physiologically to the higher altitude. If you’re at a higher altitude for weeks, your body will begin to adapt. No matter the length of time you plan to stay at high altitude, it’s important to eat and hydrate right.
Tip #1: Consume Adequate Calories
Weight loss is a concern when spending time at high altitudes. Now’s not the time to lose weight, even if you’ve wanted to shed 15 pounds. You want your body to get enough energy to fuel your adventure. If you’re losing weight on your trip, that is a sign that you need to eat more.
Possible Reasons for Weight Loss
+ You might not have access to as much food as you need on the mountain
+ Your energy expenditure (amount of energy your body uses) increases at high altitude
+ You are exerting more effort because of the difficulty of the terrain or the nature of your trip
+ Appetite is sometimes decreased
+ Eating more calories can help your body adapt to altitude and exercise. It can also help your immune system, which can be compromised at a higher altitude.
Tip #2: Consume Carbohydrate Rich Foods
Your body also needs more carbohydrates at high altitudes. Adrenaline, noradrenaline, and cortisol are all elevated with exercise at altitude. These hormones increase the use of carbohydrates for fuel. Carbohydrate is also your body’s preferred energy source, especially at high altitudes. Researchers recommend that at least 60% of your intake be from carbohydrates. This can be done by eating foods and drinking fluids that contain carbs.
Carbs | Bread, Pasta, Fruit, Potatoes, Milk, Rice, Quinoa, Tortillas, Sports Drinks
Tip #3: Consume Adequate Protein for Recovery
There isn’t much information about protein intake at altitude and how it may affect muscle growth. It’s probably safe to assume that you’ll need at least as much protein at a higher elevation than at sea level. Eating about 20-30 grams of protein after exercise and enough overall protein throughout the day is probably sufficient.
Tip #4: Don’t Fear Fat
Like protein, we don’t know much about ideal fat intake at higher elevations. However high-fat foods tend to be higher in calories, which is good for eating enough overall calories to prevent weight loss.
Fat |Jerky, Chocolate, Nuts , Olive & Coconut Oil, Butter
Tip #5: Load up on Iron Before your High Altitude Trip
You want to start your trip with adequate iron stores. Attempting a high-altitude adventure with low iron stores will leave you feeling fatigued. If you plan a high-altitude climb or climb at high altitude frequently, it’s worth checking your iron. Go to a physician at least six weeks before your trip and ask for some blood work to be drawn to test your iron stores. If you have any abnormalities, talk with your doctor and/or sports dietitian about supplementation and adding iron-rich foods to your diet.
Iron | Fortified Grains, Beef, Spinach, Lentils, Kidney Beans, Organ Meats, Eggs
Tip #6: Hydrate
High elevations make it easier to become more dehydrated (which is a bad thing) because your respiratory and urinary water losses are greater. This translates into less overall blood volume in your body. This means your heart rate may increase, but the cardiac output (the amount of blood pumped by the heart per minute) decreases.
Why is this a Problem?
For each heartbeat, your muscles and other tissues aren’t getting the same blood and oxygen delivered to them that they are used to. Heat regulation also becomes more difficult. According to one study, there is about a 3% decrease in exercise capacity for every 300 meters above 1500 meters. Imagine hiking a tough route at high altitude when you’re not used to it. Perceived effort is increased. To make matters worse, sleep is also usually compromised at high altitudes. Drinking enough can help you feel better.
How Much & What types of Fluid Should I Drink?
Fluid needs are around 3-5 liters daily, a lot, especially if you struggle to drink enough. Some studies have shown that drinking a beverage with carbohydrates and electrolytes (sports drinks) is better at hydrating than water alone at altitude. You need extra fluids because of increased fluid loss through respiration and sweat from dry air. There’s some evidence that good sleep patterns and adequate hydration can help prevent symptoms of altitude sickness. Drink regularly and don’t rely on thirst, as this might not indicate how often you need to drink.
With extra attention to your food and fluid intake, your high-altitude adventure can be successful. Beat fatigue and dehydration by remembering to consume extra calories, carbohydrates, protein, and fluids.
HOW TO EAT FOR BACKPACKING IN EXTREME CONDITIONS
– By Jill Kott & Aaron Owens Mayhew, MS, RDN
Article
“If you’re used to hiking in temperate climates, you may be surprised to learn that your calorie needs will increase when backpacking in colder climates. Shivering alone can burn up to 400 calories in one hour. Wind speed and trekking conditions, such as snow and ice, can increase energy expenditure, increasing your calorie needs. Whether post-holing your way through deep snow or kicking steps to scale a snowy mountainside, you’re likely working harder in these extreme conditions than in a temperate climate.
Pro Tip: Consistent Eating Times
Eat every 60-90 minutes. Consume carbs with every meal and snack
Why?
Glycogen stores, also known as your body’s carbohydrate stores, can be depleted within 1-3 hours, depending on how hard you work. If your glycogen stores become depleted, your body will break down your muscles to create fuel. Eating frequently can prevent your glycogen stores from being used up quickly. Consuming carbs with every meal and snack will keep fuel in the tank and protect against muscle breakdown.
Nutrition at High Altitude
Your body also requires more carbohydrates at high altitudes. The hormones adrenaline, noradrenaline, and cortisol are all elevated with exercise at altitude, increasing the use of carbohydrates for fuel. Researchers recommend that athletes backpacking at altitude consume at least 60% of their daily calorie intake from carbohydrates.
For example, if you need 5000 calories in a day:
5000 calories x 60% = 3000 calories = 750 g carbs
Typically, 20-30 g carbs per snack bar, 60-80 g carbs per one of our entree recipes
If you eat 3 meals:
60-80 g x 3 meals = 180-240 g carbs
That leaves 510-570 g of carbs to be eaten in snacks. That’s a lot of snacks!
Cold Climate Hydration Needs
Even though you may not feel like you’re dripping in sweat, hydration needs increase during cold climate backpacking. Water is lost through your respiratory system due to low humidity and an increased breathing rate as you work hard to scale the wintery terrain. It is possible to sweat up to 1 liter (32 oz) of fluid per hour due to the warm, humid environment created under your winter clothing. There are a variety of barriers to drinking fluids that can lead a backpacker to become dehydrated in cold climates, such as water bottles freezing at night when temperatures drop.
Heat Acclimatization
Heat acclimatization refers to physical adaptations that occur after prolonged exposure to a hot natural environment. These bodily adaptations reduce strain on the body and improve endurance in hot climates. This process can take anywhere between 5 to 14 days. By allowing the body to adjust to the hotter climate before beginning strenuous activity, you also reduce your risk of serious heat-related health complications like heat stroke. If possible, try taking a few days to adjust to the heat if you travel to a much hotter climate than your home. This is a simple yet effective way to make backpacking in extreme conditions a little bit easier.
Pro Tip: Arrive at your hot climate destination a few days before heading out on the trails to give your body time to acclimate.
Hot Climate Calorie Needs
Calorie requirements for backpacking in hot climates are increased due to increased cardiovascular function as the body works to dissipate heat and increase sweat gland activity. It is estimated that energy needs can increase between 0.5-18% at temperatures between 86°F (30°C) and 104°F (40°C). Energy requirements for exercise in hot climates vary depending on heat acclimatization. The more acclimatized you are to the heat, the less your energy needs increase.
Hot Climate Hydration Needs
It is important to stay properly hydrated when backpacking in the heat. Excessive dehydration can decrease exercise performance and increase the risk of heat illness. Heat illness is an umbrella term that includes heat rash, cramps, heat exhaustion, and heatstroke. Hydrate before hitting the trails! Drink ½ – ¾ L of fluid 4 hours before starting the activity.
Signs & Symptoms of Dehydration
+ Thirst
+ Unusual fatigue
+ Lightheadedness
+ Headache
+ Dark urine
+ Dry mouth
+ Infrequent urination
+ Rapid heartbeat
How Much Should I Drink on the Trails?
Aim to drink about 0.5-1.0 liter per hour while on the trails. An accurate way to measure your hydration needs is by weighing yourself before and after a day hike to see how much water weight was lost. Make sure to weigh yourself naked to get the most accurate results possible. Replenish with 24 oz (750 mL) of fluid for each lb lost. You can use this as a reference in the future when you need to hydrate but don’t have the ability to check your weight.
Is it Possible to Overhydrate?
It is also possible to over-hydrate, which can cause electrolyte levels to drop too low. When sodium levels in the blood drop below 130 mmol/L, this is called hyponatremia. Hyponatremia is very serious as it can cause seizures, kidney damage, coma, and potentially death. If you notice that you weigh more after a day hike, you likely drank too much water and should cut back next time.
Signs of Hyponatremia
Bloated stomach, Puffy fingers and ankles, Bad headache, Confusion
HOW MUCH WATER SHOULD YOU DRINK TO STAY HYDRATED?
– Saima S. Iqbal (Scientific American)
The amount of water and electrolytes needed for proper hydration vary from person to person. Extreme heat is sending unprecedented numbers of Americans to emergency departments—and to untimely deaths. Scientists, clinicians and public health officials know that people need to stay hydrated to prevent heat-related illnesses. But it can be hard for an individual to figure out how much liquid is enough; needs can vary a lot depending on circumstances and body type. In search of some actionable guidance, Scientific American spoke with physicians and researchers about how to hydrate during a heat wave (or any other weather condition).
Why is it especially important to hydrate in extreme heat?
Heat-related illness can occur whenever people are exposed to hot outside temperatures, particularly those above 90 degrees Fahrenheit (32 degrees Celsius). Humid climates make sweating less effective and increase the threat, says Stavros Kavouras, director of the Hydration Science Lab at Arizona State University.
High temperatures leach water from a person’s body, which reduces blood volume and forces the heart to work harder to support other essential organs. Dehydration, or severe water loss, in turn limits sweating, feeding a cycle of overheating. At its most innocuous, a spike in core body temperature can cause painful muscle cramps in people exercising outdoors. But heat-related illness can take the form of a more serious condition known as heat exhaustion, which can progress to a potentially lethal one called heat stroke.
Knowing the various signs of heat-related illness can save lives. “When I’ve seen people who progressed into heat stroke, it was because they weren’t aware what was happening to them, and the people around them didn’t know they were unwell,” says Sheri Belafsky, an occupational and environmental medicine physician at UC Davis Health.
Common symptoms of heat exhaustion are profuse sweating, fatigue and nausea. The condition itself isn’t fatal, but repeated cases can cause long-term health effects such as chronic kidney disease. Heat stroke occurs at body temperatures of 104 degrees F (40 degrees C) and above, can cause confusion, loss of consciousness and seizures. People who don’t receive emergency medical attention will undergo major organ failure.
What heightens the risk of dehydration?
People who spend long periods of time outside or are physically active, such as outdoor laborers and athletes, are most at risk. Age and medical status can also make dehydration more likely. Older adults sweat less efficiently, and the bodies of pregnant people and children have greater difficulty regulating body temperature. A broad swath of medications, including beta-blockers, stimulants, antipsychotics and antidepressants, make it harder for the body to detect or defend against dehydration. People with heart or kidney issues also risk their conditions worsening.
How can if you tell if you’re properly hydrated?
Thirst is a delayed and often shaky indicator of dehydration, Kavouras says. Our ability to detect thirst decreases as we age, and certain medications such as antidepressants and weight-loss drugs can dampen the signal. Experts suggest that people keep water bottles nearby and track how much they drink. Major health organizations advise women to take in 1.6 to 2.1 liters of water per day and men to take in two to three liters—but those recommendations increase in the heat. A well-hydrated person should urinate every two to three hours, and their urine should generally be pale yellow (though an individual’s diet and medication can sometimes alter the baseline color).
For people who are outdoors in extreme heat, it helps to drink a glass of water every half hour, says Brandee Waite, a sports medicine doctor at UC Davis Health. Overhydration is rare and usually only occurs if someone drinks more than a liter of fluid per hour.
Does only water count for hydration?
Nope! Many foods, particularly fruits and vegetables, contain water. But people do need to consume liquids of some kind, in addition to their meals, to meet health guidelines. Beverages such as milk and some fruit juices are mostly water. People who dislike the taste of plain water can try flavoring their drinks—or even making at-home popsicles, says Sarah Eby, a sports medicine specialist at Mass General Brigham and Spaulding Rehabilitation. Drinks that contain caffeine or alcohol, however, cause people’s body to lose more water and should be consumed in moderation when the weather is extremely hot. Waite recommends, for instance, that people at picnics or outdoor parties alternate a glass of water with each alcoholic drink.
When should a person replenish their electrolytes?
As we sweat, we lose small amounts of important minerals such as sodium, potassium and magnesium. Such electrolytes help our muscles and nerve cells function. Most people’s diet contains enough electrolytes to make up for what they lose by perspiring. But those who sweat a lot—either from prolonged heat exposure or intense physical activity that lasts more than an hour—should consider consuming electrolyte products, such as sports drinks or gummies.
The method of delivery, be it powder, tablet or gel, doesn’t affect the body’s absorption of electrolytes. The ingredient list is more important; effective products are rich in salt and contain small amounts of sugar. For a sports drink, that might look like 450 milligrams of sodium and less than 30 grams of sugar per 24 ounces (0.7 liter) of liquid, Eby says. Small amounts of sugar speed up fluid absorption, but larger amounts have the opposite effect: too much sugar can cause diarrhea and thereby dehydrate the body.
People who decide to make their own electrolyte drinks at home should follow recipes that are simple and cheap, Waite suggests. A mixture of apple juice, water and salt can suffice—though “you don’t want to make it so [salty] that your face puckers as you drink it,” she adds.
The kidneys often filter out extra electrolytes, but drinking too many can cause muscle cramps, nausea, diarrhea and a fast heart rate. It’s safest to stick to existing products that offer serving size recommendations and to reach out to physicians for more precise guidance when necessary.
How much does hydration matter outside of a heat wave?
Water plays a vital role in “every single physiological function of the body,” Kavouras says. Despite this, more than half the world’s population fails to meet normal daily hydration guidelines. The kidneys can stave off dehydration by secreting less liquid, which keeps symptoms minor for most people. But the consequences of even mild water deficits, or “underhydration,” accumulate over time. Inadequate hydration can worsen day-to-day cognitive and physical functions—and some research has linked chronically high sodium levels to faster aging and a higher risk of chronic diseases, such as diabetes, dementia and heart failure.