Temperatures are rising, and we’re feeling more and more excited for summer sports here in Colorado. But with summer heat comes some concerns all you athletes would benefit from learning a little bit more about heat-related illnesses.
Don’t be fooled—it doesn’t take Mississippi-level humidity and 90 + degrees to lead to these illnesses; anyone participating in intense training or outdoor activity during the summertime is at risk for developing any number of heat-related ailments.
Join me as I dive into this hot topic, exploring the most common heat illnesses in athletes and cool strategies to beat the heat!
The Heat is On: What Are Heat Illnesses?
Heat illness is a broad term that refers to a variety of conditions including exercise-associated collapse, exercise-associated muscle cramps (“heat cramps”), heat exhaustion, and exertional heat stroke (among others)1. These conditions occur as a result of increased stress on your body, and often threaten the body’s internal temperature regulation system.
Your body has various ways of regulating body temperature, but in the hotter seasons or even just with increasing exercise intensity, your body begins to rely more on evaporation through sweating (or, as I like to call it, “glistening”).
When things like decreased air circulation, poorly ventilated clothing, increased exercise intensity/duration, dehydration, or underlying medical conditions come into play, your body’s ability to dissipate heat diminishes, and your core temperature begins to rise. This is when things can get spicy.
But first let’s consider the milder side of things: Exercise-associated-collapse and heat cramps
Two Milder Forms of Heat Illness
Ever run a race and seen the person next to you collapse right after crossing the finish-line? (Or ever BEEN that person?) Odds are, this is a classic case of exercise-associated collapse. It’s considered a “milder” form of heat illness because it doesn’t involve a rise in core body temperature.
The long and short of why this happens has to do with training adaptations that many endurance runners undergo, including a higher cardiac output and lower resting heart rate. When you exercise, your muscles act as a “second heart” to pump blood back to your heart. But with a sudden cessation in exercise, like at the end of a race, the blood may pool in your lower extremities and result in lightheadedness, dizziness, and ultimate collapse.
Heat cramping, on the other hand, often has to do with an imbalance in electrolytes and improper hydration. Heat cramps commonly occur in the beginning of training, when your body has not been properly conditioned. To dissipate heat, your body sweats, but sweating occurs at a higher rate than re-hydration. The loss of salt in sweat can lead to electrolyte imbalances, causing intense, painful cramping in the abdomen, legs, or upper body. The good news is, once replenished with proper nutrition and hydration, you can usually resume your sport.
Both exercise-associated collapse and heat cramps can be quickly mitigated with cooling efforts, such as rehydration, ice massage, and getting into a cooler environment. For collapse, also try elevating the feet above heart level. For cramping, stretch out the affected muscle.
Now onto the spicier side of heat illness: Heat Exhaustion and Exertional Heat Stroke
Heat exhaustion and exertional heat stroke differ from heat cramps and collapse because they result in an increase in your core body temperature. Your body’s temperature regulation system becomes overwhelmed and cannot efficiently disseminate heat to cool itself.
Your body usually stay at around 36.1-37.2 degrees Celsius (for those of you who find Celsius a foreign concept like me, that’s about 97-99 degrees Fahrenheit2).
So let’s return to the fact that in hotter environments, or when your body start producing more heat, you rely on sweating (glistening) as the main source of heat loss. This occurs when body temperatures reach about 37 deg C (98.6 deg F).
Loss of sweat leads to dehydration. Dehydration causes decreased sweat output in order to retain fluid. Now, you aren’t able to lose heat and your core temperature continues to rise.
Organs begin to feel the effect of reduced blood flow. Blood pressure decreases and the heart can’t pump blood efficiently. In heat exhaustion, your core body temperature reaches up to, but not over, 40 deg C/104 deg F3.
Symptoms of heat exhaustion include the following3:
- Increased heart rate and decreased blood pressure
- Extreme weakness
- Dehydration and loss of electrolytes
- Lightheadedness, fainting
- Coordination impairments
- Headache
- Persistent muscle cramping
- Abdominal cramps, nausea, diarrhea
What differentiates heat exhaustion from heat stroke is:
1. Heat stroke results when your core body temperature increases over 104 degrees F leading to:
2. Central nervous system symptoms
Heat stroke is considered a medical emergency and can be fatal if left untreated.
Symptoms of heat stroke include those of heat exhaustion as well as3:
- Disorientation, confusion
- Irritability
- Emotional instability
- Altered consciousness
- Coma or seizure
Treatment of heat exhaustion and heat stroke includes immediate cooling of the body, using full-body immersion, removal from hot environments, rehydration, monitoring of symptoms and rectal body temperature, and in the case of heat stroke, alerting emergency medical services.
Whew-that’s a lot! So how do you keep your cool knowing all of this?
Six Sizzling Solutions for Preventing Heat Illness:
- Practice HEAT ACCLIMATIZATION: gradually increase exercise duration and intensity over 10-14 days in the heat.
- Stay HYDRATED: not only does dehydration lead to heat-related illness, but even performance declines with as low as a 2-3% decrease in body weight from sweat loss4.
- Wear sweat-wicking, loose clothing
- Get enough sleep and proper nutrition
- Avoid training during the hottest times of the day when possible
- Avoid certain medications and substances, like stimulants and caffeine, that increase heart rate
So, what do you think? Are you ready to beat the heat? Keep in mind that these tips also apply to any kind of intense exercise in “normal” environmental conditions—heat illness can occur despite higher temperatures and high humidity. If you want more help and advice knowing how to mitigate the effects of heat illness, feel free to check in with your friendly physical therapists here at Alpine Fit PT!
If you’re curious about more ways to prevent heat illness, talking with a Doctor of Physical Therapy is a great place to start. Click here to apply for your 30-minute free discovery visit today
Sources:
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4596225/
- https://www.ncbi.nlm.nih.gov/books/NBK499843/#:~:text=The%20normal%20core%20body%20temperature,40%20C%20(104%20F).
- https://www.uptodate.com/contents/exertional-heat-illness-in-adolescents-and-adults-epidemiology-thermoregulation-risk-factors-and-diagnosis
- https://ncaaorg.s3.amazonaws.com/ssi/nutrition/SSI_PerformanceHydrationFactSheet.pdf
- https://journals.lww.com/acsm-msse/Fulltext/2007/03000/Exertional_Heat_Illness_during_Training_and.20.aspx
- https://www.nata.org/sites/default/files/Heat-Illness-Task-Force-Consensus-Statement.pdf
- https://www.ncaa.org/sports/2016/7/20/heat-and-hydration.aspx
