2017 is on track to be the second hottest year on record, according to Climate Central, and it’s only expected to get hotter from here on out. One simple way to beat such heat is to never set foot outside ever again—an option that’s been considered by many of us after purchasing an air conditioner. But what would actually happen to you if you never saw the light of day again? Turns out: A lot, none of it good.
First off, you’d experience a serious vitamin D deficiency, which can be damaging for a few reasons. When sunlight hits the skin, it reacts with cholesterol (which is also found in the skin) to create a new molecule called calcitriol, or “activated” vitamin D. Calcitriol is vital for absorbing calcium from the food you consume, ultimately leading to bone growth and strength. But without sunlight, this reaction would never occur, and you’d likely experience osteoporosis (a condition in which the bones become weak and brittle) and decreased immune function as a result.
Furthermore, studies also suggest that vitamin D helps prevent cancer, cardiovascular disease and depression, which is why people living in colder climates are more likely to suffer from SAD, otherwise known as the “winter blues.”
But, sure, maybe you bought a giant vat of Vitamin D pills. It’s not only the sun your body would miss if you became a recluse, though: A 2016 study found that spending just 30 minutes in nature (a park or backyard will do—anything that’s not concrete) per week significantly reduces high blood pressure and depression. In fact, other studies found that just looking at the color green has psychological benefits—namely, improved mental clarity.
Contrary to what you may think, you’d also be more exposed to illnesses if you became a permanent homebody, since you’d be constantly breathing recycled air. That’s why people tend to come down with colds during winter—they’re cooped up indoors breathing recirculated (germ heavy) air.
To sum it up, while staying indoors forever might sound appealing for any number of reasons—it’s a tough world out there—you’re surprisingly better off outside than inside.