Temperatures are expected to soar into the mid 90s over the next couple of days, with afternoon heat indices exceeding 100 degrees in much of Tennessee. The National Weather Service’s Morristown weather forecast office has extended a Heat Advisory for Scott County and the rest of East Tennessee through Friday evening.
In the Heat Advisory, the NWS offers several tips from the federal Occupational Safety & Health Administration (OSHA): Take frequent breaks in shaded or air-conditioned environments, drink plenty of water, stay out of the sun, and check up on relatives and neighbors.
The NWS also advises calling 911 if you suspect someone might be suffering from heat stroke, reminding that it is considered a medical emergency.
Heat stroke is the most severe form of heat-related illness. Unlike heat exhaustion, which often improves with rest and cooling, heat stroke is a medical emergency that requires immediate treatment. Without rapid intervention, it can permanently damage the brain, heart, kidneys, and muscles, and even become fatal.
What is heat stroke? In a nutshell, it occurs when the body’s natural cooling system fails. Normally, sweating helps regulate body temperature. But during prolonged exposure to extreme heat or strenuous activity in hot weather, the body can no longer cool itself effectively. As a result, the body’s core temperature rises rapidly — typically to 104 degrees or higher. At that point, organs begin to suffer damage.
Because heat stroke occurs when the body’s natural cooling system — sweating — fails, someone who is suffering from heat stroke may have hot, dry skin. Other symptoms can include: Altered mental state, such as confusion, agitation or irritability, slurred speech, or even unconsciousness; nausea or vomiting; rapid breathing; racing heart rate; and headache.
While heat stroke receives less attention than hurricanes or tornadoes, extreme heat kills more Americans in an average year than any other weather-related hazard. The risk increases dramatically during prolonged heat waves, especially when overnight temperatures remain warm and the body never has a chance to recover.
That’s precisely what the region is dealing with this week. The NWS’s Heat Advisory was not issued simply because daytime heat indices are expected to reach or exceed 100 degrees, but also because nighttime temperatures are stuck in the low to mid 70s each night, offering no chance for relief after the sun goes down.
Who is at risk of heat stroke? Pretty much anyone, but some people are more susceptible than others. Those include adults over age 65, infants and young children, people with heart disease, diabetes or obesity, people taking certain medications, such as diuretics, antihistamines and some psychiatric medications, and of course, outdoor workers and athletes. People without air conditioning are also at a greater risk, as is anyone who becomes hydrated.
There isn’t one specific air temperature that causes heat stroke. However, meteorologists use the heat index as an indicator, because humidity prevents sweat from evaporating. The heat index combines temperature and humidity for a “feels like” temperature — similar to the wind chill index in the winter. The high humidity is why the heat index is expected to exceed 100 degrees each day this week even on the Cumberland Plateau, although the actual temperature will be in the low 90s.
As a general rule, heat stroke is unlikely when the heat index is below 80, but heat-related illnesses begin to become more common during prolonged exertion once the heat index reaches 80 or above. At 90 degrees or higher, heat exhaustion becomes increasingly likely for anyone who doesn’t take frequent breaks and stay hydrated. When the heat index exceeds 103 degrees is when heat stroke becomes a significant risk, especially with physical activity or prolonged exposure.
And an important reminder: Direct sunlight does not factor into the heat index, but can make conditions feel another 10 to 15 degrees hotter.
Heat stroke is dangerous. The U.S. Centers for Disease Control & Prevention (CDC) recommends calling 911 if heat stroke is suspected. While waiting for help to arrive, move the person to a cooler area, remove excess clothing, and use any available means to cool them down, such as applying cold water or ice packs. One of the best ways to rapidly cool down someone suffering from heat stroke is to immerse them in cold water, if possible. However, experts warn not to force fluids if a person is confused or unconscious.
Untreated heat stroke can lead to serious complications, including organ damage or death. Medical experts often refer to the “golden 30 minutes.” Research has shown that rapidly cooling a person’s body within 30 minutes of collapse dramatically improves survival and reduces the risk of permanent disability.
Even with treatment, studies have found mortality rates ranging from 10% to 30% with heat stroke, depending on age, overall health, and how quickly cooling begins. Without prompt treatment, mortality can exceed 50%, and severe cases may approach 80%.
In addition to the aforementioned precautions, experts suggest drinking water throughout the day, even if you don’t believe you are thirsty; wear lightweight, light-colored clothing; and, of course, never leave children or pets in parked vehicles.
The bottom line: heat stroke isn’t simply “getting too hot.” It is a rapidly progressing medical emergency that can become fatal in less than an hour. If someone becomes confused, collapses, or develops signs of heat stroke during hot weather, call 911 without hesitation and begin cooling them immediately. Fast action can mean the difference between a full recovery and a tragedy.
