A heat cramp consists of spasmodic muscle pain typically associated with exercise and physical exertion in, but not limited to, hot environment. Individuals that are most susceptible to cramping include athletes, miners, and military personnel. Heat cramps occur as a result of excessive sweating, thus loss of water and sodium occur, with little or no replacement of sodium, or both sodium and water [1] [2]. This leads to hyponatremia. Cramps may start abruptly and last from several minutes to hours. The muscles in the limbs are usually affected.

Heat cramps are distinguished from cramps due to muscle fatigue by their unresponsiveness to measures such as stretching and cooling, as well as more severe pain [3] [4] [5]. The mechanism by which these cramps occur is thought to be a contraction of the extracellular compartment, which concentrates neurotransmitters and ions, leading to hyper-excitable nerve terminals. They usually affect alternating groups of voluntary muscle, resulting in the perception of what is sometimes described as a 'wandering' cramp. Some patients may experience prodromal muscle twitching shortly before the full onset of cramps. As an episode of cramping continues, it becomes more widespread, involving a greater number of muscles. Heat cramps may be seen as a form of heat illness; some literature suggests that the former may be considered as one of the symptoms of heat exhaustion.

Heat cramps in certain occupations have been successfully treated by drinking saline. Similarly, athletes can use this method to avoid cramping [6]. The same protective effect is not achieved with hydration alone. This provides further evidence that the heat cramps occur due to loss of sodium in sweat. Resting and decreasing physical activity at the first signs of cramping can also prevent heat cramps [7].

• Severe Pain

  Heat cramps are distinguished from cramps due to muscle fatigue by their unresponsiveness to measures such as stretching and cooling, as well as more severe pain. [symptoma.com]

  Severe pain and carpopedal spasm may incapacitate the hands and feet. Temperature is normal, and other findings are unremarkable. The cramp usually lasts minutes to hours. Diagnosis is by history and clinical evaluation. [merckmanuals.com]

  Symptoms include cramping of the muscles that comes on suddenly and causes severe pain. Cramping may last from minutes to hours. [fairview.org]

  What's happened is that your muscle has tightened and shortened, causing sudden, severe pain, explains Debra Zillmer, MD, orthopedic surgeon and medical director of the Gundersen Lutheran Sports Medicine Clinic in La Crosse, WI. [prevention.com]

• Military Personnel

  Individuals that are most susceptible to cramping include athletes, miners, and military personnel. [symptoma.com]

  This affects young persons like athletes, manual labours, construction workers, military personnel and firemen. Symptoms of heat stroke The symptoms of heat stroke include: Raised body temperatures of over 40 C (104 F). [news-medical.net]

• Turkish

  Look up "heat cramp" at Merriam-Webster Look up "heat cramp" at dictionary.com In other languages: Spanish French Italian Portuguese Romanian German Dutch Swedish Russian Polish Czech Greek Turkish Chinese Japanese Korean Arabic Advertisements Word of [wordreference.com]

• Muscle Cramp

  Preventing Muscle Cramps Until we learn the exact cause of muscle cramps, it will be difficult to say with any confidence how to prevent them. [sportsmedicine.about.com]

  Muscle cramps rarely occur in a strong and rested muscle. Cramps invariably become a factor in athletic performance after the muscle has endured significant stress. [faqs.org]

  Barely detectable muscle fasciculations or "twitches" in the affected muscles can rapidly progress to debilitating muscle cramps in just 20 to 30 minutes. [ncbi.nlm.nih.gov]

• Painful Muscle Cramps

  Heat cramps are painful muscle cramps caused by too much salt and water loss from a result of either too much heat and physical exhaustion or a combination of both. The cramps usually occur in the muscle that has been used most strenuously. [standardfirstaidcourses.ca]

  Heat cramps are painful muscle cramps. Working hard or exercising in hot weather can cause heat cramps. Older people and children get heat cramps more easily. [drugs.com]

  Cramping that affects the function of muscle groups throughout the entire musculoskeletal system is a result of the same mechanisms that trigger more localized and painful muscle cramping, which is typically isolated in the calf and hamstrings. [faqs.org]

• Muscle Twitch

  Heat cramps are muscle twitches or spasms, usually in the abdomen, arms, or legs that are associated with heat and dehydration. Sweating depletes the body of water and salt. [sharecare.com]

  Some patients may experience prodromal muscle twitching shortly before the full onset of cramps. As an episode of cramping continues, it becomes more widespread, involving a greater number of muscles. [symptoma.com]

  I could feel muscle twitches in my quads, and my quads were burning. I had to slow down as I felt the cramp coming on. Then wham! Like a sledgehammer to my leg, the cramp hit and I had to stop and rub it out. [active.com]

• Carpopedal Spasm

  Severe pain and carpopedal spasm may incapacitate the hands and feet. Temperature is normal, and other findings are unremarkable. The cramp usually lasts minutes to hours. Diagnosis is by history and clinical evaluation. [merckmanuals.com]

• Myalgia

  Shock DIC TABLE 3 Signs and Symptoms of Potentially Life-Threatening Heat-Related Illnesses Heat cramps Elevated body temperature Thirst Muscle cramps Sweating Tachycardia Heat exhaustion Same as heat cramps, plus : Nausea/vomiting Headache Malaise/myalgias [aafp.org]

• Increased Sweating

  It can also be a sign of low sodium, due to increase sweating in the hot weather. [sharecare.com]

  Symptoms can include: increased thirst weakness fainting muscle cramps nausea and/or vomiting irritability headache increase sweating cool, clammy skin elevation of body temperature, but less than 104 F (40 C) What to Do: Bring your child to a cooler [kidshealth.org]

  Acclimatization to hot environments usually occurs over 7-10 days and enables individuals to reduce the threshold at which sweating begins, increase sweat production, and increase the capacity of the sweat glands to reabsorb sweat sodium, thereby increasing [emedicine.medscape.com]

• Throbbing Headache

  Heatstroke Throbbing headache, dizziness or fainting, sweating stops, skin turns red, dry and hot, nausea and vomiting, rapid heartbeat, shortness of breath Call 911, then move the victim into the shade or inside a cold room. [wjla.com]

  Primary symptom: body temperature higher than 105 degrees Fahrenheit or 40.6 degrees Celsius.Other symptoms include: warm and dry skin, fever, increased heart rate, shallow breathing, loss of appetite, nausea, vomiting, throbbing headache, dizziness, [theydiffer.com]

The diagnosis is based on the clinical signs and symptoms, as well as the history surrounding the occurrence of the heat cramp. Other tests that may be carried out include:

• Urea and electrolytes: Results often show normal or high sodium levels. This should not be misinterpreted to mean that plasma sodium is present in adequate amounts. On the contrary, it is a result of the body's compensatory mechanisms, in which it tries to keep the extracellular environment constant despite losses through sweat.
• 24-hour urine collection: This may be useful in predicting the likelihood of an individual suffering from future cramps, especially if the kidneys' excretion of sodium in the urine is reduced.
• Electromyography: This test proves that heat cramps are disorganized over-activity of nerve endings and muscle, as a result of a shrunken extracellular compartment and low sodium. It does so by the positive findings of abnormal electrical activity and fasciculations [8].

• Hyponatremia

  This leads to hyponatremia. Cramps may start abruptly and last from several minutes to hours. The muscles in the limbs are usually affected. [symptoma.com]

  In contrast, heat cramps can occur in physically fit people who sweat profusely and replace lost water but not salt, thereby causing hyponatremia. [merckmanuals.com]

  Pathophysiology Hyponatremia and volume depletion from profuse sweating Provoked by muscle overload or Fatigue, dehydration or electrolyte disturbance IV. [fpnotebook.com]

  Sweat contains a large amount of sodium, and drinking fluids with inadequate sodium content may result in a serious low-sodium condition called hyponatremia. [webmd.com]

1. Bergeron MF. Heat cramps during tennis: a case report. Int J Sport Nutr. 1996;6(1):62-68.
2. Stofan JR, Zachwieja JJ, Horswill CA, Murray R, Anderson SA, Eichner ER. Sweat and sodium losses in NCAA football players: a precursor to heat cramps? Int J Sport Nutr Exerc Metab. 2005;15(6):641-652.
3. Jung AP, Bishop PA, Al-Nawwas A, Dale RB. Influence of hydration and electrolyte supplementation on incidence and time to onset of exercise-associated muscle cramps. J Athl Train. 2005;40(2):71-75.
4. Bentley S. Exercise-induced muscle cramp: proposed mechanisms and management. Sports Med. 1996;21(6):409-420.
5. Schwellnus MP, Derman EW, Noakes TD. Aetiology of skeletal muscle ‘cramps’during exercise: a novel hypothesis. J Sports Sci. 1997;15(3):277-285.
6. Bergeron MF. Heat cramps: fluid and electrolyte challenges during tennis in the heat. J Sci Med Sport. 2003;6(1):19-27.
7. Donoghue A, Sinclair MJ, Bates GP. Heat exhaustion in a deep underground metalliferous mine. Occup Environ Med. 2000;57(3):165-174.
8. Layzer RB. The origin of muscle fasciculations and cramps. Muscle Nerve. 1994;17(11):1243-1249.