Backpacking involves a long and steady aerobic workout with fitness benefits that rival other more intense, higher impact activities. Although backpacking is a non-competitive recreational activity with a low chance of burn-out, the constant climbing and descending can lead to cramping and injury. Besides the overuse of the muscles, leg cramping is exacerbated by inadequate eccentric contraction strength, dehydration, electrolyte imbalance from sweating, and insufficient carbohydrate intake.
Common Causes of Leg Cramps When Hiking
When you are backpacking, the muscles in your leg contract while in motion and stretch out when motion is completed, or another muscle moves it in the opposite direction. The leg muscles are continuously shortening and lengthening to stabilize you while you climb and descend on rugged terrain.
Backpacking involves both concentric muscle contraction (muscles shortening under tension) and eccentric muscle contraction (muscles lengthening under tension). Concentric muscle contraction is used for hiking uphill, cycling, and lifting weights, while eccentric action is used for reducing speed when hiking downhill.
Lack of eccentric muscle training
Research shows that most leg cramps, soreness, and injury are from eccentric contraction. As you 
walk downhill, your body gains momentum. To slow (or stop) that momentum, your knee and hip muscles must contract eccentrically to reduce the impact on your weight-bearing lower body. Most of our daily activity, including strength training, does not involve enough eccentric motion. For instance, treadmills have an incline setting for concentric strength training, but no decline setting for eccentric training. Unsurprisingly, these muscles are not adapted, and you will need to train for eccentric movement, specifically the quadriceps. The best way to train these muscles is by walking downhill (or downstairs) with a loaded pack or ankle weights. Performing squats are another exercise you can do to build eccentric muscle strength and reduce cramping and soreness.
For a complete list of workouts, see backpacker’s hike further, hike stronger and section hiker’s 10 exercises to become a badass hiker.
Downhill hiking also places significant stress on your ankle, knee, and hip joints. If you have problems in these areas, read our article on saving your knees hiking downhill.
Dehydration
Dehydration is the most common reason for leg cramping while hiking. Adequate fluid intake is crucial because it is needed to process nutrients in your cells and ultimately provide energy.
Since water molecules are small, they continuously move inside and outside the cell membrane, keeping cells hydrated. When the body becomes dehydrated, the fluid outside of the cells decreases, and water molecules gravitate inside cells to interact with proteins, sugars, and other molecules. This net reduction in fluid causes nerve endings to flatten, hyper excite, and spontaneously discharge, which is felt as a muscle spasm. Maintaining proper hydration prevents dramatic shifts of fluid in your cells, which contributes to abnormal muscle contractions and muscle cramping. Therefore, if you experience cramping while hiking, the first thing you should do is drink water.
Electrolyte Imbalance
Besides losing water from sweating, you also lose electrolytes, especially sodium and chloride (salt). Salt depletion could be the culprit if drinking water does not reduce cramping while backpacking. Muscles sometimes involuntarily fire when salt is depleted, causing intense pain. Thus, eat a salty snack and drink water as soon as you feel cramping.
The fastest way to get sodium in your body is to add it to your drinking water. Add 1/4 to 1/2 tsp of salt, about one salt packet, to a standard (32 fl oz, about 1 L) water bottle. If you are sodium deficient, the cramps will subside within minutes.
- The sodium deficit required to prompt muscle cramping is not well understood. However, studies estimate that sweat-induced sodium losses between 20% to 30% are all it takes to produce severe muscle cramping.
- Because of the high salt content of most backpacking food, you can likely replace sodium losses during meals without adding extra sodium. However, if you are sweating profusely and your skin is chalky with salt, you will need to consume extra salt along with electrolytes such as potassium and magnesium to enhance recovery. Munch on salty snacks while hiking, and eat a wide variety of trail meals.
Another culprit of cramping is caused by an electrolyte imbalance of potassium, calcium, and magnesium, which are all essential for muscle function. Luckily, only a small amount is needed, and these are easy to get in a healthy diet. At every opportunity, eat trail foods that are high in these minerals.
- Good vegan sources of magnesium – nuts, seeds, oats, dark chocolate, spinach, lentils, soy, beans, brown rice, and quinoa.
- Good vegan sources of potassium – dried fruit & vegetables (apricots, apples, figs, coconut, prunes, banana, plantains, dates, raisins, tomato, carrots), avocado (eat fresh), spinach, beans, lentils, and potato flakes.
- Good vegan sources of calcium – soy, spinach, hummus (sesame), almonds, chia seeds, and beans.
Sweat losses vary according to the type of activity, the intensity of exercise, and environmental conditions. According to Gale Bernhardt, USA Triathlon coach, an average person sweats between 0.8 to 1.4 liters (roughly 27.4 to 47.3 oz.) per hour during exercise. This table shows typical electrolyte losses per two pounds of sweat, which is equivalent to one liter (about one quart) of water volume.
| Electrolyte | Average amount per 2 lbs of sweat, about 1-quart | Food reference |
| Sodium | 800 mg (range 200-1,600) | nearly any packaged food |
| Potassium | 200 mg (range 120-600) | 2 tbsp sunflower seed = 240 mg |
| Calcium | 20 mg (range 6-40) | 1 tbsp chia seed = 170 mg |
| Magnesium | 10 mg (range 2-18) | 1 tbsp peanut butter = 25 mg |
Most muscle cramps are caused by sodium losses rather than magnesium and potassium because we lose more sodium in sweat than the other electrolytes. However, all electrolytes are essential for retaining water in the body. If you are deficient in any of these minerals, you may remain dehydrated and at risk for cramps, no matter how much water you drink.
Inadequate Carbohydrate Consumption
Carbohydrates are the preferred source of energy used by the body. Carbohydrates, particularly complex starches, are the most efficient fuel source for the muscles. Backpacking and other low-intensity endurance activities require a higher daily intake of carbs to keep up with energy demands. Not eating enough carbohydrates can deplete stores of glycogen, causing impaired muscle functioning, which will lead to muscle cramps.
Focus on eating carbohydrate-rich trail food containing multiple sources of electrolytes. Some of the entrees that I would recommend by Outdoor Herbivore include –
Hot Meals containing Carbohydrates & Electrolytes
- High Elevation Rice Cereal – brown rice, almonds, raisins, soy milk
- Lickety Split Lentils – brown rice, lentils, spinach, peanut
- Chickpea Sesame Penne – sesame seed, chickpea, spinach
- Blackened Quinoa – quinoa & beans
- PeaNutty Matchsticks – coconut & peanut
- Chunky Chipotle Chili – quinoa & beans
- Savory Lentil Simmer – lentils & coconut
- Naked Freckle Burrito – brown rice & beans
- Speedy Spud Soup – potato, cheese
No-Cook Meals & Snacks containing Carbohydrates & Electrolytes
- Fiesta Quinoa Salad – quinoa, beans
- Lazy Lentil Salad – lentils, sunflower seed
- Coconut Chia Peel – banana, coconut, dates, chia seed
- Instant Hummus – chickpeas, sesame seed
- Sunny Sunflower – quinoa, beans, sunflower seed
- Toasted Sunburst Muesli – oats, nuts, seeds, raisins, dates, soy milk
- Blueberry Maple Crunch – oats, almonds, sunflower, coconut, soy milk
- Midnight Mocha Chia – banana, dark chocolate, oats, coconut, chia seed
- Cocoa Nutty/CinnaMonkey Chomps – banana, coconut
Now you know what you can do to diminish leg cramps. Before you hit the trail, start by strengthening the quadriceps with eccentric exercise. When on the trail, make sure you keep a proper diet and drink plenty of water. Beyond that, give yourself multiple rests on the days when you are climbing and descending more than you are used to.
Article sources:
Backpacker: Strength: Incorporate Eccentric Training to Climb With Power — And Descend Without
Vegetarian Sports Nutrition By D. Enette Larson-Meyer
Muscle Cramps during Exercise V Is It Fatigue or Electrolyte Deficit? Michael F. Bergeron National Institute for Youth Sports & Health at Sanford, Sanford USD Medical Center, Sioux Falls, SD