Heat Related Illness and Risk

Not to state the obvious, but it’s hot out and there is a real heat related illness risk. Summer has swept the country bringing high temperatures, storm systems and often high humidity. Additionally, with this hot weather also comes a desire to enjoy the longer hours of sunshine and be outside.  We all associate summer with those outdoor activities like baseball, golf (a personal favorite of mine and Sue’s!), and being on the water.  

So, this begs the question – how hot is too hot?  When should sports practices be cancelled? When should we try to squeeze in 18 holes?  When are we better off to just head to the air conditioned movie theatre and hibernate inside?  What is the risk of heat related illness?

According to the National Weather Service, it is not enough to just consider the outside temperature, we need to be looking at the Heat Index.  The heat index is the “real feel” or apparent temperature – what the temperature feels like to the human body when relative humidity is combined with the air temperature.  As humidity levels and temperature both increase, our body’s ability to cool itself off through evaporating perspiration goes down, and we feel warmer.  For example, if the air temperature is 100°F and the relative humidity is 55%, the heat index will be 124°F.  Alternately, if the air temperature is 100°F and the relative humidity is 15%, the heat index is 96°F.  This is where that saying, “but it’s a DRY heat” comes from!  There is real heat related illness risk at these temperatures.

According to new research from the University of Roehampton in England, the human body may lose the ability to rid of excessive heat and stop functioning optimally when outside temperatures reach beyond 104 degrees Fahrenheit.  Ideally, we would be able to stay in the thermoneutral zone – the range of temperatures in which the body doesn’t have to increase its metabolic rate or exert more energy to maintain its ideal core temperature of 98.6 degrees Fahrenheit.  We drop below the thermoneutral zone at approximately 82 degrees Fahrenheit, when our body must start exuding more energy to maintain the ideal body temperature.  It is also important to note that in the study there was evidence that resting metabolic rate was higher at higher humidities, even at the same temperature, meaning that humidity also plays a large role in the metabolic rate.  

Because the human body is amazing, we actually can adapt to how our body’s handle the heat based on where we live.  For example, people living in warm climates tend to acclimatize and not increase their body temperature and in turn their metabolic rate as much. Likewise, people living in cool-freezing temperatures may get more of a response to heat exposure as they are not acclimatized to the heat.  This occurs as the body tries to maintain homeostasis, or the regulation of physiological processes that allow for our systems of organs and tissues to function efficiently and properly.  

If you do need to be out in the heat, it is critically important that you remain vigilant to how your body is responding to the temperature.  According to GoodRX.com, young children or babies, adults over 65, pregnant women, people who work outside, and people with underlying medical conditions or who take different medications are especially vulnerable to developing heat-related injuries.  

When spending time outdoors, it is also important to consider if you will be spending time in direct sunlight or have access to shade, if you will be exposed to cooling effects from the wind, and if you are exerting yourself by working or exercising outdoors.  

If you do need to be outdoors during high heat index, please consider the following recommendations, courtesy of the Centers for Disease Control and National Public Radio:

• Limit outdoor activity, especially during the middle of the day when the sun is hottest if possible.
• Wear and reapply sunscreen as indicated on the package.
• Schedule workouts and practices earlier or later in the day when the temperature is cooler.
• Pace activity. Start activities slow and pick up the pace gradually.
• Hydrate, hydrate and hydrate some more!  Drink more water than usual, and don’t wait until you’re thirsty to drink more. Muscle cramping may be an early sign of heat-related illness.
• Monitor the condition of your companions, and have someone do the same for you
• Eat at least one hour before physical activity – the digestion process actually creates more body heat!
• Wear loose and lightweight clothing, as well as a hat.  Materials like sweat-wicking athletic wear allow your skin to perspire and cool itself.  Materials like wool or cotton will keep heat close to your body. 
• These will all help reduce heat related illness and risk

It is critical that you consider your environment and overall health when planning your outdoor activities – activities like swimming are a great option.  Water is a great way to manage hot weather, and causes less stress on the body. Yoga is also a good alternative to cycling or running for a full body workout.  

We hope you are able to find some fun activities this summer to enjoy the great outdoors, but also stay cool and comfortable!  

All the best, 

Brian