Health and Safety How to Prevent Cramps and Illness in the Heat By Elizabeth Quinn, MS Elizabeth Quinn, MS Elizabeth Quinn is an exercise physiologist, sports medicine writer, and fitness consultant for corporate wellness and rehabilitation clinics. Learn about our editorial process Updated on November 27, 2019 Medically reviewed Verywell Fit articles are reviewed by board-certified physicians and nutrition and exercise healthcare professionals. Medical Reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more. by Michael Lau, PT, DPT, CSCS Medically reviewed by Michael Lau, PT, DPT, CSCS Facebook LinkedIn Twitter Michael Lau, PT, DPT, CSCS, is a licensed physical therapist, strength and conditioning coach, and co-founder of The Prehab Guys. Learn about our Medical Review Board Print Obradovic/Getty Images Table of Contents View All Table of Contents Causes Treatment Prevent Heat Illness Prevent Muscle Cramps Heat cramps are painful muscle spasms that occur in the arms, legs, or abdomen that usually occur after several hours of exertion in the heat. In addition to muscle cramps, other symptoms of heat cramps may include faintness, dizziness, weakness, and excessive sweating. Usually, an athlete suffers from heat cramps after several hours of the exertion and excessive sweating that results in dehydration. Causes Muscle cramps are more common during exercise in the heat because sweat contains fluids as well as electrolytes (salt, potassium, magnesium, and calcium). When these nutrients, particularly sodium, fall below a certain level due to excessive sweating, the incidence of heat cramps increases. The exact cause of heat cramps is unknown, but common theories include:Altered neuromuscular controlDehydrationDoing a new activityElectrolyte depletionMuscle fatiguePoor conditioning While all these theories are being studied, there's more evidence that the "altered neuromuscular control" hypothesis is the principal pathophysiological mechanism the leads to exercise-associated muscle cramping (EAMC). Altered neuromuscular control is often related to muscle fatigue and results in a disruption of muscle coordination and control. Why Am I So Tired After Long Runs? Treatment As soon as you recognize any of the symptoms of heat illness, take the following actions: Stop activity and sit quietly in a cool place.Drink a sports beverage with electrolytes (you can make your own sodium-based solution with 1/4 teaspoon table salt mixed in a quart of water).Gently stretch and massage the cramping muscle.Hold the joint in a stretched position until the cramp stops.Seek medical attention for heat cramps if they do not subside in one hour. Most muscle cramps are not serious. If your muscle cramps are severe, frequent, constant or otherwise of concern, see your doctor. Prevent Heat Illness Remember, it is easier to prevent heat illness than to treat it once symptoms develop. To minimize your risk of developing heat cramps, it's important to hydrate well. Do not drink alcohol or beverages with caffeine before exercise because they increase the rate of dehydration. Drink plenty of fluids before and during exercise and replace lost electrolytes such as sodium, potassium, and magnesium with food or a sports drink (drink 16 to 20 oz/hour). Staying hydrated helps, but it's also important to guard against overheating. Avoid exercising during the hottest time of day; train closer to sunrise or sunset.If you are going to exercise in hot weather, acclimatize to the heat for about a week before intense exercise. If you feel your abilities start to diminish, stop the activity and seek out a cool, shaded place.Use sunscreen to prevent sunburn, which can limit the skin's ability to cool itself.Wear a hat with a brim.Wear light, loose clothing, so sweat can evaporate. Better yet, invest in some clothes that wick moisture from your skin to the outer layer of the clothing where it can evaporate more easily. Brands like CoolMax®, Drymax®, Smartwool or polypropylene all have this property. Prevent Muscle Cramps Until we learn the exact cause of muscle cramps, it will be difficult to say with any confidence how to prevent them. However, experts and athletes alike recommend fitness fundamentals, such as warming up before exercise, improving fitness, avoiding excessive muscle fatigue, and stretching regularly, paying particular attention to the calves, hamstrings, and quadriceps. How to Weatherproof Your Workouts For 365 Days of Safe Outdoor Exercise 3 Sources Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Schwellnus MP. Cause of exercise associated muscle cramps (EAMC)--altered neuromuscular control, dehydration or electrolyte depletion? Br J Sports Med. 2009;43(6):401-8. doi:10.1136/bjsm.2008.050401 Jahic D, Begic E. Exercise-associated muscle cramp-Doubts about the cause. Mater Sociomed. 2018;30(1):67–69. doi:10.5455/msm.2018.30.67-69 Miller KC, Stone MS, Huxel KC, Edwards JE. Exercise-associated muscle cramps: causes, treatment, and prevention. Sports Health. 2010;2(4):279–283. doi:10.1177/1941738109357299 Additional Reading American Orthopaedic Society for Sports Medicine. Muscle cramps. Updated June 2017. By Elizabeth Quinn, MS Elizabeth Quinn is an exercise physiologist, sports medicine writer, and fitness consultant for corporate wellness and rehabilitation clinics. See Our Editorial Process Meet Our Review Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit