When the mid-summer heat sets in, taking your run or walk outdoors can feel like stepping into a furnace. To escape the heat, you might find yourself weaving from one side of the street to the other, wanting to be in the shade at all times.
But does staying in the shade actually make a measurable, scientific difference to your body? Or is it just a mental trick?
The short answer: It absolutely makes a massive difference. Choosing a shady trail over a sun-baked road can make a huge difference. Here is the scientific breakdown of sun versus shade.
The 15-Degree Heat Index Deception
We’ve all checked our weather apps before heading out and seen a warning for a “Feels Like” temperature (or Heat Index) of 105°F.
What most people don’t realize is a critical caveat from the National Weather Service: The Heat Index is calculated assuming you are in the shade with a light wind. Because the mathematical formulas used to determine the heat index don’t account for direct solar radiation, stepping into full; direct sunlight can add up to 15°F to the felt temperature.
Solar Radiation: The Heavy Backpack You Didn’t Know You Were Wearing
Why does the sun make such a difference? It all comes down to radiant heat transfer. When you exercise in direct sunlight, your body has to manage heat from two different sources:
So, the next time you want to go on a walk/ run in the summer heat, find the shade!
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