The Science of Summer
The Physiology Behind Why Our Pace Slows Down In The Summer & What We Can Do About It
By Alyssa O’Krent of AOK PT
Welcome Summer Warriors!
As the summer months bring higher temperatures, many runners find their performance affected by the heat. Understanding the physiological reasons behind this can help you better prepare, adjust your training, and most importantly, your mindset.
My friends at Trail Roots created an insightful blog post about acclimatizing to the Texas Heat. This was incredibly useful information. At AOK PT, patient education is one of our top priorities which is why we’re excited to share the why behind the summer slogginess.
Running in the heat can significantly affect a runner's performance due to several physiological factors:
Thermoregulation: The human body needs to maintain a core temperature within a narrow range for optimal function. Running generates heat, and in hot conditions, the body works harder to dissipate this excess heat. Sweating and increased blood flow to the skin are the primary mechanisms for cooling down. However, these processes are less efficient in high temperatures, leading to an increase in core temperature.
Cardiovascular Strain: To dissipate heat, more blood is directed to the skin for cooling. This reduces the amount of blood available to transport oxygen to the muscles. The heart compensates by pumping more blood, increasing heart rate. This added cardiovascular strain can lead to earlier fatigue and slower running speeds.
Dehydration: High temperatures increase sweating, which can lead to significant fluid loss. Dehydration reduces blood volume, making it harder for the cardiovascular system to supply oxygen. It also makes it more difficult to remove metabolic waste, which is the culprit of most heat-related illnesses.
Electrolyte Imbalance: Along with fluids, sweating causes a loss of electrolytes like sodium, potassium, and magnesium. These electrolytes are crucial for muscle function, and their imbalance can result in muscle cramps, weakness, and reduced performance.
Metabolic Changes: In the heat, the body’s metabolism may shift. Glycogen, the stored form of glucose in muscles, is used up more quickly, leading to earlier onset of fatigue.
Neurological Factors: The brain also plays a role in regulating performance in the heat. As core temperature rises, the brain may signal the body to slow down to prevent overheating, a protective mechanism against heat-related damage.
I know you might be thinking, that’s fascinating Dr. Alyssa, but what can I do about this?
Find a running community. Groups like Trail Roots that have coaches leading their pack will help normalize the adjustment your body will go through as you run together.
Nerd out, just a liiiittle more! Use a race equivalency calculator to determine your adjusted pace based on the heat and humidity. You’ll be amazed at how much slower your adjusted pace may be.
Hydrate like an athlete. Incorporate electrolytes and intake adequate fluid (⅔ body weight in ounces is a good goal to get started).
In summary, running in the heat imposes additional stress on the body’s systems, from thermoregulation and cardiovascular function to fluid balance and metabolism, all contributing to slower running speeds.
