Beat the Heat:
Prevention, Recognition and Management of Exertional Heat Illnesses
By. Kevin Morris, MS, ATC
May 29th 2018, 4:30pm. The Maryland Terrapins football team took the field for a scheduled offseason workout following a disappointing 4-8 record the year prior. 16 minutes of stretching and warm-ups, followed by a conditioning test consisting of ten 110 yard sprints.1 During rep 8, 19 year old offensive lineman Jordan McNair was bent over at the waist complaining of lower back cramps. 94 minutes later, he was on board an ambulance heading to the ER.1 Exertional Heat Stroke presents with a core body temperature of 105*F or above.2 McNair’s core body temperature reached 107*F.3 He died 2 weeks later from Exertional Heat Stroke, the number one cause of sudden death in sports.1,2
Exertional Heat Illnesses (EHIs) have plagued athletes across all sports. From Exercised Associated Muscle Cramps to Exertional Heat Stroke, healthcare professionals have established effective, preventative strategies to minimize the risk of EHIs. This article will present these strategies below, but first, it is important to understand what the different types of EHIs are and how to manage them?
Recognition and Management
1. Exercise-Associated Muscle Cramps
- Exercise-associated muscle cramps (EAMCs) are “Sudden or sometimes progressively and noticeably evolving, involuntary, painful contractions of skeletal muscle during or after exercise.”2,5,6 Though most common in hot conditions, EAMCs can present during exercise in cool and temperature controlled climates.2,5,6
- How To Treat
- Stop activity. Start passive stretching and massage along with ice to reduce muscle tension.2,7–9 Drink/eat sodium containing fluids to help return the body to normal fluid electrolyte distribution.2,7–9
2. Heat Syncope
- Heat syncope refers to a fainting episode or dizziness that occurs from prolonged standing or sudden rising from a sitting or lying position.2,10 Heat Syncope usually arise during the first 5 days of heat exposure before cardiovascular adaptations are complete.2,10
- How To Treat
- Stop activity, move to a shaded area and lay the person down flat on their back with their legs elevated above the level of their heart.2,10 Cool the skin with ice bags or cold towels and rehydrate.2,10 Continue to monitor vitals.2,10
3. Heat Exhaustion
- Heat exhaustion is “The inability to effectively exercise in the heat, secondary to a combination of factors, including cardiovascular insufficiency, hypotension, energy depletion, and central fatigue.”2,12 This type of EHIs reaches a core body temperature of 104*F.2,12 Excessive salt and water loss through excessive sweating contribute to your body experiencing heat exhaustion.2,12
- How To Treat
- Stop activity. Remove any excess equipment (i.e. helmet, shoulder pads) and clothing to help facilitate cooling.2,12,13 Move person to a shaded area and immediate begin rapid cooling of wet ice towels, ice packs, fans, and ice bath.2,12,13 Place person in supine position with legs elevated to above the level of the heart to promote venous return. Provide fluids to the person.2,12,13 While treating, a rectal temperature reading should be obtained. to get a reading of core body temperature.2,12,13 Temperatures can be gathered orally, though it is not as accurate. When in doubt, call 911.
- Rhabdomyolysis is a type of medical condition associated with heat stress resulting in a rapid breakdown and death of muscle tissue.14 As muscle tissue dies, protein substrates leak into the bloodstream and can result in kidney failure.14 Those suffering from rhabdomyolysis likely experience muscle pain/cramps, dark urine, weakness, and overall exercise intolerance.14
- How To Treat
- Stop Activity. Drink fluids. Seek immediate care at the nearest medical facility.14
5. Exertional Heat Stroke
- The most severe EHIs, Exertional Heat Stroke occurs when core body temperature reaches 105*F or over.2,13,15,16 An imbalance in our thermoregulatory system is seen in Heat Stroke as a result of either excessive heat production (metabolic activity of working muscles) or heat loss inhibition (decreased sweating response or inability to evaporate sweat.2,13,15,16 First sign of Heat Stroke is normally CNS dysfunction (i.e. collapse, irritability, confusion, seizures, loss of consciousness).2,13,15,16 The longer our core temperature is elevated above 105*F, the greater likelihood of systemic organ failure.2,13,15,16
- How to Treat
- Stop activity. Call 911. Begin rapid cooling immediately with cold water immersion.2,17,18 Remove clothing and equipment while the person is immersed in the cold water.2,17,18 If cold water immersion is not available, use wet ice towels, ice packs, fans, and other cooling devices. 2,17,18 While treating, a rectal temperature should be obtained. to get a reading of core body temperature.2,17,18
1. I’m just warming up Coach.
- Individuals should gradually acclimate to the heat over a 7-14 day span, progressively increasing intensity, duration and phasing in protective equipment.2,19 The first 2-3 weeks of activity presents the greatest risk of EHIs. 2,19
2. I think I need to stay home from school today.
- If you are sick, you may be more susceptible to EHIs.2,19 Do yourself and your team a favor, stay home and get better.
3. Does Red Bull count as a good drink before activity?
- Individuals should maintain good hydration before, during, and after activity.2,20 Eat or drink sodium containing fluids and foods to help replace sodium losses in sweat and urine.2,20 And please do not drink Red Bull before activity… or ever for that matter.
4. It’s so humid outside I can barely breathe!
- Hot and humid environments can increase the risk of EHIs.2,21 Our body pulls heat from the environment and sweat cannot evaporate.2 Coaches, and healthcare professionals should always consult with the graph below when determining practice structure and if to cancel activity.22
5. Coach, I don’t feel so well.
- Recognition is the number one way of preventing EHI’s. If you are experiencing any heat related symptoms (i.e. cramping, dizziness, lightheadedness, headaches, fatigue, flushed skin, excessive sweating) speak up and take some time to cool down. This will hopefully negate any further risk of EHIs.
As we transition to Summer, let us remember that player safety does not only deal with internal factors such as flexibility, mobility, strength, etc… but also external factors like environmental conditions. Be cognizant of the weather and pack appropriately with the right attire and fluids. Enjoy your summer, and BEAT THE HEAT!
1. Maese R, Stubbs R. U-Md. releases report on Jordan McNair, laying out timeline that led to player’s death. Washington Post. https://www.washingtonpost.com/sports/colleges/u-md-board-of-regents-releases-report-on-jordan-mcnair-laying-out-timeline-that-led-to-players-death/2018/09/21/49331ea0-bda9-11e8-b7d2-0773aa1e33da_story.html. Published September 21, 2018. Accessed May 30, 2019.
2. 1062-6050-50.9.pdf. https://natajournals.org/doi/pdf/10.4085/1062-6050-50.9.07. Accessed May 30, 2019.
3. Jordan McNair of Maryland Terrapins died of heatstroke after team workout. http://www.espn.com/college-football/story/_/id/24343021/jordan-mcnair-maryland-terrapins-died-heatstroke-team-workout. Accessed May 30, 2019.
4. EHI-mgmt-and-Cold-Water-Immersion.pdf. https://www.jaxsmp.com/wp-content/uploads/2017/02/EHI-mgmt-and-Cold-Water-Immersion.pdf. Accessed May 30, 2019.
5. Muscle Cramps during Exercise-Is It Fatigue or Electrolyte D... : Current Sports Medicine Reports. https://journals.lww.com/acsm-csmr/Fulltext/2008/07001/Muscle_Cramps_during_Exercise_Is_It_Fatigue_or.9.aspx. Accessed May 30, 2019.
6. Schwellnus MP. Cause of exercise associated muscle cramps (EAMC)--altered neuromuscular control, dehydration or electrolyte depletion? Br J Sports Med. 2009;43(6):401-408. doi:10.1136/bjsm.2008.050401
7. Schwellnus MP, Drew N, Collins M. Increased running speed and previous cramps rather than dehydration or serum sodium changes predict exercise-associated muscle cramping: a prospective cohort study in 210 Ironman triathletes. Br J Sports Med. 2011;45(8):650-656. doi:10.1136/bjsm.2010.078535
8. Factors associated with a self-reported history of exercise-associated muscle cramps in Ironman triathletes: a case-control study. - PubMed - NCBI. https://www.ncbi.nlm.nih.gov/pubmed/21430526. Accessed May 30, 2019.
9. Bertolasi L, De Grandis D, Bongiovanni LG, Zanette GP, Gasperini M. The influence of muscular lengthening on cramps. Ann Neurol. 1993;33(2):176-180. doi:10.1002/ana.410330207
10. Carter R, Cheuvront SN, Vernieuw CR, Sawka MN. Hypohydration and prior heat stress exacerbates decreases in cerebral blood flow velocity during standing. J Appl Physiol Bethesda Md 1985. 2006;101(6):1744-1750. doi:10.1152/japplphysiol.00200.2006
11. Heat Stroke. Dr David Geier - Sports Med Simpl. January 2011. https://www.drdavidgeier.com/heat-illness/. Accessed May 30, 2019.
12. Kenefick RW, Sawka MN. Heat exhaustion and dehydration as causes of marathon collapse. Sports Med Auckl NZ. 2007;37(4-5):378-381. doi:10.2165/00007256-200737040-00027
13. American College of Sports Medicine, Armstrong LE, Casa DJ, et al. American College of Sports Medicine position stand. Exertional heat illness during training and competition. Med Sci Sports Exerc. 2007;39(3):556-572. doi:10.1249/MSS.0b013e31802fa199
14. CDC - Heat Stress - Heat Related Illness - NIOSH Workplace Safety and Health Topic. https://www.cdc.gov/niosh/topics/heatstress/heatrelillness.html. Published November 14, 2018. Accessed May 30, 2019.
15. Exertional Heat Stroke in Competitive Athletes : Current Sports Medicine Reports. https://journals.lww.com/acsm-csmr/FullText/2005/12000/Exertional_Heat_Stroke_in_Competitive_Athletes.6.aspx. Accessed May 30, 2019.
16. Casa DJ, Guskiewicz KM, Anderson SA, et al. National Athletic Trainers’ Association Position Statement: Preventing Sudden Death in Sports. J Athl Train. 2012;47(1):96-118.
17. Cold water immersion: the gold standard for exertional heatstroke treatment. - PubMed - NCBI. https://www.ncbi.nlm.nih.gov/pubmed/17620933. Accessed May 30, 2019.
18. Immersion treatment for exertional hyperthermia: cold or temperate water? - PubMed - NCBI. https://www.ncbi.nlm.nih.gov/pubmed/20559063. Accessed May 30, 2019.
19. The Inter-Association Task Force for Preventing Sudden Death in Collegiate Conditioning Sessions: Best Practices Recommendations. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3396308/. Accessed May 30, 2019.
20. Casa DJ, Armstrong LE, Hillman SK, et al. National Athletic Trainers’ Association Position Statement: Fluid Replacement for Athletes. J Athl Train. 2000;35(2):212-224.
21. Sawka MN, Leon LR, Montain SJ, Sonna LA. Integrated physiological mechanisms of exercise performance, adaptation, and maladaptation to heat stress. Compr Physiol. 2011;1(4):1883-1928. doi:10.1002/cphy.c100082
22. Could deadly wet bulb temperatures become a thing in our climate change future? : collapse. https://www.reddit.com/r/collapse/comments/68hp9p/could_deadly_wet_bulb_temperatures_become_a_thing/. Accessed May 30, 2019.