Electrolytes for Hiking: How Much Sodium You Need

Electrolytes for hiking matter most on long, hot, sweaty days, when you lose sodium, potassium and other minerals faster than normal meals replace them. On a short walk in cool weather, plain water and a snack are fine. On a six-hour climb in summer, getting sodium right can be the difference between finishing strong and ending the day with cramps, a headache or worse. This guide covers how much you need, food vs tablets, and how to avoid both dehydration and over-drinking.

This is general information. People with high blood pressure, heart or kidney conditions, or on medications affecting fluid or sodium should follow their doctor's advice.

What electrolytes do

Electrolytes are minerals that carry an electrical charge in body fluids. They help regulate fluid balance, nerve signals and muscle contraction.

Sodium is by far the most important electrolyte lost in sweat. Potassium, magnesium and calcium losses are small, and a normal diet with fruit, nuts and dairy covers them.

When do you need electrolytes?

Signs you're a salty sweater include white salt streaks on your hat or shirt, stinging sweat in your eyes, and craving salty food after hiking.

How much sodium per hour?

Research on endurance exercise shows sweat sodium varies widely between people, so there's no single number. The ACSM position stand on exercise and fluid replacement recommends that fluids containing sodium and potassium can help replace losses during prolonged exercise, especially when sweat losses are high. A practical starting range for hikers:

Try a level in training and adjust. If you finish with cramps, a headache and salt-crusted clothes, you probably need more. If your hands and feet swell and you feel bloated, you may be taking more water than you need.

How much water?

Fluid needs vary with heat, effort, pack weight and body size. Many hikers drink about 0.5 litres per hour in moderate conditions and up to 1 litre per hour in heat. Drink to thirst, check your urine colour (pale yellow is good), and plan water stops ahead. Work out how much to carry with the water carry calculator.

Salty snacks vs electrolyte tablets

Food and drink both work. Hiking burns a lot of calories, so salty snacks do double duty. See high protein hiking snacks, beef jerky recipe and estimate energy needs with the hiking calorie estimator.

Homemade electrolyte drink

Mix into 1 litre of water:

1. ¼ teaspoon table salt (about 575 mg sodium)
2. 2 tablespoons sugar or honey (about 25 g carbs)
3. Juice of half a lemon or a splash of orange juice for flavour and a little potassium

This gives roughly 575 mg of sodium and 100 kcal per litre, similar to many sports drinks. For a hot day, sip one litre over one to two hours alongside plain water.

Hyponatremia: too much water, not enough sodium

Exercise-associated hyponatremia happens when blood sodium falls too low, usually from drinking far more fluid than you lose over many hours. It's a real risk on long, hot hikes, especially for slower hikers who drink heavily "to stay ahead". Symptoms include nausea, headache, confusion, bloating, swollen hands and, in severe cases, seizures.

The Wilderness Medical Society hyponatremia guidelines recommend drinking to thirst rather than on a fixed schedule and eating salty snacks during prolonged activity. Anyone with confusion or vomiting after a lot of drinking needs urgent medical help; don't give them more plain water.

Electrolytes on multi-day trips

On backpacking trips, meals usually supply enough sodium if they include salty foods. Dehydrated meals, ramen, instant mash, soup packets, cheese, salami and jerky are all high in sodium. Many hikers add one electrolyte tablet a day in hot weather and one at camp after a big day. Plan meals with the trail meal planner and see backpacking food for a week.

Before and after the hike

• Before: have a normal meal with some salt and drink 400 to 600 ml of water an hour or two before you start. See what to eat before a hike.
• During: drink to thirst, eat salty snacks every hour or two.
• After: a salty meal with protein and carbs, and fluids until your urine is pale. Ideas in what to eat after hiking.

Muscle cramps: is it electrolytes?

Cramps on the trail are often blamed on low salt, but research suggests muscle fatigue plays a bigger role than electrolyte loss for many people. Cramps that appear late in a long, steep day, in the muscles doing the most work, are more likely fatigue-related. Cramps alongside heavy sweating, salty clothes and a lot of plain water are more likely helped by sodium. Practical steps for both: pace yourself on climbs, stretch the cramping muscle gently, eat a salty snack and keep drinking to thirst. Training on similar terrain before a big trip reduces fatigue cramps more than any supplement.

Hiking with kids

Children heat up faster and are less likely to drink on their own. Offer water often, pack salty snacks they actually like, and take breaks in the shade. Sports drinks are fine on hot days, but water and food are enough for most family hikes. More in hiking snacks for kids.

Quick electrolyte checklist for a long day hike

• 2 to 3 litres of water, or a plan to refill
• One electrolyte tablet or sachet per litre for hot sections
• Salty snacks for every two hours on the trail
• A salty lunch, such as a wrap with cheese and jerky

Bottom line

For most hikes, water plus salty snacks is all you need. On long, hot or strenuous days, aim for a few hundred milligrams of sodium per hour from food, tablets or a homemade drink, drink to thirst, and watch for signs of both dehydration and over-drinking.

Sources: ACSM position stand, Exercise and fluid replacement (2007); Wilderness Medical Society Clinical Practice Guidelines for Exercise-Associated Hyponatremia, 2019 update; food sodium values from USDA FoodData Central. General information, not medical advice.