Heatstroke 101: What You Need To Know

Knowing the signs of heatstroke are important for anyone who works in a high temperature environment. This includes those that work outdoors, where hot, humid days produce heat-related illnesses in rapid fashion. At particular risk are people who labor outside and those who participate in organized sports, as the vast majority of heatstroke cases are brought on by extended physical exertion. Even those who are otherwise fit and healthy can be affected by heatstroke, so prevention and treatment methods should be standard in any high risk environment.

What are the signs of heatstroke?

Heatstroke is one of several heat-related illnesses, but is widely considered to be the most severe. Unlike other forms of heat-related illnesses, like heat cramps, heat rash or heat exhaustion, heatstroke is an immediate medical emergency that can result in death or permanent injury if not treated promptly. Recognizing what heatstroke looks like is the first step in preserving life, and the signs look like this:

  1. Elevated temperature – Heatstroke is usually diagnosed symptomatically, but the defining characteristic of the condition is a temperature in excess of 105 degrees Fahrenheit. At this temperature, the body’s organs are at risk of sustaining damage. Indicator tools like heat cards can alert workers to dangerous outdoor temperatures, but the only way to confirm the presence of heatstroke is to get an accurate temperature reading from the affected person. Rectal thermometer readings are generally regarded as the most accurate.An important note – fever and heatstroke are not the same thing. Fevers are caused by physiological mechanisms in response to infection or illness. Heatstroke is a product of the body’s thermoregulatory mechanisms being overwhelmed. When the body’s thermoregulation is defeated, it is normally due to a combination of exertion, excessive environmental heat and impaired heat loss.
  2. Dizziness, mental confusion or weakness – These symptoms are often present before true heatstroke sets in, so they should serve as troubling red flags. Heat exhaustion is the standard term for heat illness that results in mental impairment or weakness, and always precedes heatstroke.
  3. Excessive sweating or a complete lack of sweating – Excessive sweating may be present in people who are exerting themselves during the onset of heatstroke. A complete lack of sweating is an alarming symptom, as it suggests that the body is severely dehydrated and unable to remove heat through sweating. At this stage, rapid temperature increase is imminent and potentially fatal.
  4. Loss of consciousness – As heatstroke progresses, loss of consciousness is possible and signals a high risk of neurological or cardiological complications. Loss of consciousness is usually an indicator of a poorer prognosis, even if the patient is able to fully recover from the episode. Lack of consciousness can also make some forms of treatment more difficult, so prevention should be emphasized so that people do not lose consciousness due to heatstroke.

If any of these signs are present, it is paramount that the person is immediately removed from the high temperature environment and administered treatment. As heatstroke is an emergency medical situation, emergency personnel should be alerted at once.

How to Prevent and Treat Heatstroke

According to The Journal of Emergency Medicine, heatstroke kills more than 600 people in the U.S. every year. The vast majority of these deaths occur in people who are at a higher risk of heatstroke, such as the very young or old, people with other medical conditions and people on medication that affects their thermoregulatory mechanisms. However, death is still a possible outcome in anyone who does not receive treatment. And death is not the only severe consequence of heatstroke. Researchers with the University of Chicago Medical Center studied dozens of patients affected by the 1995 Chicago heat wave, and found that even when patients fully recovered from heatstroke, they were often profoundly affected by the episode, even years later. Specifically, the researchers found that about half of the studied patients died within the following year, and many others had severe functional impairments related to the heatstroke.

In short, heatstroke prevention is not just a life or death situation – it is also about preserving the patient’s quality of life over the long haul. For this reason, prevention is the best cure, and workplaces and sports teams can minimize the chances of heatstroke by doing the following:

  1. Know when hot is too hot – The single biggest mistake that people, managers and coaches make is not taking the heat and humidity seriously. There is often a stigma attached to taking it easy, even when it’s hot outside. This is a dangerous stigma to abide by, as the chances of rapid heatstroke increase as the temperature rises. It’s not enough to just look at the thermometer either, as high humidity can greatly increase the heat index, or the perceived outdoor temperature. On a humid day, heat indexes can run up to 10-15 degrees hotter than the listed temperature, and indexes above the 100s mean dangerous conditions for outdoor workers and athletes. When the temperature gets this hot, consider bringing activities indoors, if possible.
  2. Enforce mandatory rest periods – If work or play cannot be brought inside, then workers should be required to rest a certain amount of time every hour. For example, if temperatures are above 100 degrees outside, workers should be required to rest at least 20 minutes out of every hour, and ideally inside. As temperatures climb, rest periods should be lengthened and workers monitored to ensure they are getting enough downtime.
  3. Dress codes that emphasize heat regulation – Impaired heat loss mechanisms are a key cause of heatstroke, but this can be addressed to an extent by promoting a safe dress code. This should include light fitting clothes that allow for better ventilation, lightly colored clothing that does not absorb as much sunlight and wider brimmed hats that block sunlight from reaching the face and neck.
  4. Ready access to rehydrating fluids – Dehydration is a ubiquitous feature of heatstroke, which suggests that many people who suffer from it did not hydrate adequately prior to symptoms. The problem is that most people don’t hydrate until they become thirsty, but thirst is an inadequate measure for determining when someone has lost too much fluid. For this reason, water or electrolyte drinks should be available at all times, and workers encouraged to rehydrate regularly, even when not thirsty.
  5. Carry helpful temperature indicators like heat cards – Heat cards equipped with liquid crystal thermometers (also called thermochromic liquids) are easily portable and can provide continuous monitoring of ambient temperature. With a heat card, safety personnel and workers know exactly when exterior temperatures are entering unsafe territory.

If worksites and sports teams rigorously apply these prevention methods, the chances of anyone suffering from heatstroke will be extremely low. However, if someone is suspected of experiencing heatstroke, treatment must be applied without hesitation. The goal of treatment is to reduce the patient’s core temperature to 102 degrees Fahrenheit as quickly as possible. At this temperature, the patient is unlikely to experience further damage due to heatstroke and is also unlikely to experience “rebound” hyperthermia.

There are two methods of treatment that are generally considered to be the most effective. They include:

  1. Ice water bath immersion – Full body ice water immersion is considered to be the fastest method of temperature reduction possible. Ice water is able to bring core temperature down to 102 degrees within 20-40 minutes, which is typically fast enough to guarantee a positive prognosis. The problem with ice water bath immersion is that it is particularly uncomfortable and possibly dangerous if the patient is unconscious, as they may slip below the water and drown. Close monitoring of the patient is therefore necessary.
  2. Evaporative heat loss methods – This involves spraying the patient with water and placing a high powered fan next to the patient to wick away excess heat. Water is capable of absorbing a lot of heat in a short amount of time, so constant reapplication of water can also reduce core temperatures in a hurry. Although it is completely safe to use in unconscious patients and generally makes it easier to resuscitate the patient, if need be, it is not as effective as ice bath immersion. However, evaporative heat loss is usually easier to execute, as an ice bath is not always a feasible option.

There are other methods of reducing temperatures, including delivery of intravenous cold fluids, gastric or rectal lavage and application of cold, wet towels. None of these rival ice water bath immersion or evaporative heat loss in terms of effectiveness.

Heatstroke can be a killer, and even when it doesn’t result in death, it can leave the sufferer in poor shape for the rest of their life. To guarantee the near and long-term safety of workers or athletes, safety personnel must take heatstroke seriously and avoid it at all costs.