How do you know when you are getting close to heat stroke?
2024 has been the hottest summer of the decade and it is causing many of you to go to the ER with heat related sickness. There are several risk factors that may put you at high risk for illness relating to the heat. I have been present several times when someone collapses from heat stroke which is the most severe heat related illness. The heat can kill you if it progresses this far. It is interesting, athletes who won’t back off from their outdoor activities, and will work out in the highest heat of the day.
Heat stroke can cause a person to collapse, drop their blood pressure, act out, or pass out, or even seize, all of which are signs to call 911, and start emergency procedures: elevate their legs, if possible, place ice packs under the arm pits, around the sides of the neck, and on their groin.
The highest risk patients:
- Babies and toddlers
- are over 65
- On multiple medications
- Taking a diuretic
- Obese patients
- People with anemia and other blood conditions
- Patients with coronary heart disease
- Patients with atrial fib
- Those people who don’t drink water, just caffeinated drinks-dehydrated people
- Who have just been flying (dehydrated)
- Who are hung over (dehydrated)
- Who have been nauseated and vomiting in the days before going out and working or playing in the heat.
Ask the heat stroke victim to drink fluids if possible. Of course, make sure they stop the activity they are engaged in outside in the heat. Move them to a cool place while you are waiting for emergency help to arrive. Heat stroke can cause a vascular stroke or death, so emergency treatment is necessary. If possible, offer the victim water with electrolytes in them (NUUN-Sport) and some sugar in case they are also hypoglycemic as well. If they can’t drink, which is a side effect of heat stroke, put a wet washcloth in your mouth to suck water from it slowly.
My husband and I went on a trip to Cinque Terra, Italy with another couple last fall to hike the trails between the 5 towns that line the cliffs over the shores of Liguria. The hike was supposed to start at 8 am so we could avoid the heat of the day….and it was in the 90s and humid…but as luck would have it the transportation we had arranged for wasn’t able to take us to the starting point and we didn’t get there until 10:30. We packed several water bottles and a few snacks but we were not prepared for the 4 ½ hour trek high above the mediterranean on a trail that was 3 feet wide and involved thousands of steps up and down…we had drunk most of our water in the first 2.5 hours and were very hot and sweaty the whole time….about 40 minutes from the town of Vernazza, my husband started stumbing, and talking nonsense…he had stopped sweating and couldn’t walk….There was no place to lay him down without blocking the path and we found a shady spot for him to recline and put his feet up. I had some Nuun-sport electrolytes which I had put in my water and had been drinking, so I put 2 electolye tablets in ½ bottle of water and tried to get him to drink it…..he was delirious and refused, and I had to force him to drink…he fell asleep and we received water and cold water bottles to put around his neck from passersby.
Ideally, we would have gotten ER help which he really needed, but there was no way to get emergency care to him and at 6-4 and 230 he was too heavy to carry/drag…and remember we were on the edge of a 200 ft cliff. When he had slept 20 minutes I kept my finger on his pulse and he was thready and fast…..Thankfully he rallied and we got to Vernazza and he walked into the ocean after drinking several glasses of water to cool off and fell asleep on the beach for an hour until he was ready to get on the train back to our hotel….This was one of the scariest times of my life because I knew what to do but didn’t have the IVs, or water or ice or anything to help him. Remember this and make sure you are always prepared for the worst scenario when you are active in the heat!
So how do you know when you are getting close to heat stroke?
You feel weak and out of breath. Your pulse rises, you stop urinating, and you STOP sweating. You are getting close to heatstroke when you start to feel cold even though the ambient temperature is high. When you feel dizzy and unstable on your feet…the next thing to happen is vascular collapse
See the stages of Heat Related Illnesses below, which we are all at risk for! This is from the NEJM.
| Heat-Related Illness | Description | Treatment |
| Severe illness | ||
| Heat stroke | A multisystem, life-threatening illness characterized by elevation of the core body temperature (to >40°C) and CNS dysfunction
Classic heat stroke: most often occurs among older persons with compromised behavioral and physiological compensatory responses to heat exposure Exertional heat stroke: most often occurs among healthy persons during extreme physical exertion, which results in excessive metabolic heat generation, often but not always with concomitant ambient heat exposure |
Move patient to cool environment; manage airway, breathing, and circulation; administer rapid cooling with cold-water or ice-water immersion or other means; administer intravenous rehydration; and evacuate to emergency department after on-site cooling is performed. ICU admission is warranted for management of end-organ sequelae. |
| Moderate illness | ||
| Heat exhaustion | Profound fatigue, weakness, nausea, headache, or dizziness (or a combination of these symptoms) resulting from a decrease in body water content or blood volume due to water or salt depletion from heat exposure; mild elevation (<40°C) in body temperature may be present, but no altered mental status | Remove patient from heat; treat with rest in supine position, evaporative cooling, and intravenous or oral rehydration; monitor mental status. Delayed response to treatment warrants further evaluation. |
| Mild illness | ||
| Heat syncope | Brief loss of consciousness due to vasodilation and pooling of blood in the limbs as a result of physiological compensation to heat exposure | Remove patient from heat and treat with rest in supine position, passive cooling, and oral or intravenous rehydration. Prolonged recovery or a medical history or physical examination arousing concern for a cardiac cause if the patient has cardiac risk factors should prompt further evaluation. |
| Heat edema | Swelling of the limbs caused by peripheral vasodilation and interstitial pooling resulting from physiological compensation in response to heat exposure | Remove patient from heat and elevate the legs. Diuretic agents are not indicated. |
| Heat cramps | Painful muscle spasms in the abdomen, arms, or legs during or after activity in the heat, which often occur when excessive amounts of salt are lost during sweating from physical exertion | Remove patient from heat, treat with rest, oral electrolytes, and fluid repletion. |
| Heat rash | An inflammatory disorder of the epidermis that results from blockage of sweat glands; may be followed by superimposed bacterial soft-tissue infection. | Remove patient’s clothing; treat with evaporative cooling and glucocorticoid and antibacterial creams as needed, but avoid topical emollients; monitor for cellulitis. Advise patients to avoid hot environments and to wear loose clothing. |
* CNS denotes central nervous system, and ICU intensive care unit.
What medications increase your risk of Heat Stroke:
| Agent | Mechanism |
| Alcohol | May reduce alertness and affect judgment and perception of heat; exacerbates dehydration and affects vasodilation and cardiac contractility |
| Amphetamines | May increase metabolic heat production |
| Anticholinergics | May decrease sweat production |
| Antihistamines | May cause peripheral vasoconstriction, limiting radiative cooling |
| Antipsychotics | Interferes with hypothalamic thermoregulation |
| Benzodiazepines | May reduce alertness and affect judgment and perception of heat |
| Beta-blockers | Decreases heart rate and contractility |
| Calcium-channel blockers | Decreases cardiac contractility and compromises vascular compensatory mechanisms |
| Diuretics | May increase risk of dehydration and hypovolemia |
| Illicit drugs (e.g., cocaine, heroin, phencyclidine, and MDMA) | May increase metabolic heat production and reduce alertness and judgment |
| Laxatives | May increase risk of dehydration and hypovolemia |
| Lithium | May reduce alertness and affect judgment and perception of heat and lead to nephrogenic diabetes insipidus; levels may rise to dangerous levels and cause kidney injury in the context of dehydration |
| Serotonin-reuptake inhibitors | May interfere with hypothalamic thermoregulation |
| Thyroid agonists | May increase metabolic heat production |
| Tricyclic antidepressants | May cause peripheral vasoconstriction, thereby limiting radiative cooling, and may affect central thermoregulation |
| Weight-loss supplements that may increase metabolic rate (e.g., carnitine and green tea extract) | May increase metabolic heat production |
If you are someone who plays or works outside in the heat you should think about your risk of heat stroke and the risk of those around you. If you have heart disease, have had a stroke, or have arrhythmias, especially atrial fibrillation, you should choose not to be outside in the heat and or humidity for any length of time. Any dehydration will increase your risk of heat stroke.
For those of you who choose to continue to work, exercise or play in the extreme heat, you should have double the water you would drink on a normal day, bring electrolytes to put in every third bottle of water while you are in the heat and afterwards to recover. Remember to eat and have enough calories to maintain your blood sugar, because hypoglycemia will make it worse. Stop and rest and go inside an air conditioned room every hour if possible, make sure you have cold packs available in case you need emergency care before the ambulance gets there.
Arm yourself with enough hydration and electrolytes, cold packs and carb+protein snacks if you are not close to a place to hydrate and eat…. We all feel invincible and forget we are human…but if you stay aware of the risk you will prepare for the worst outcome and hope for the best!
