With millions in the U.S. under heat advisories, and as extreme heat continues to claim more lives, it's more important than ever to stay hydrated.
In high temperatures, it's easy to get dehydrated, and the standard recommendation of drinking eight, 8-ounce cups of water a day may not be enough, especially if you're exercising outside in the heat or doing other physical activity.
When it comes to being dehydrated, a quick skin pinch can be one way to find out if you’re losing more fluids than you’re taking in. Dehydration means your body doesn’t have enough fluids to work properly, a potentially life-threatening condition, according to the National Library of Medicine.
It can sneak up on you, so a verified TikTok user who identifies himself as Dr. Karan Raj, a surgical doctor with the U.K.'s National Health Service, posted a video pointing to the skin pinch, or skin turgor test, as a way of checking.
What is the skin pinch test?
Simply squeeze the skin on one of your finger knuckles for a moment, then let go.
If you’re well hydrated, the skin will return to its original position immediately, Raj said. But if you’re dehydrated, it loses its elasticity and will stay in a pinched or “tented up” position for a moment, he added.
Can the skin pinch test tell you if you're dehydrated?
Samantha Cassetty, a registered dietitian who is a nutrition and wellness expert in New York, recommends pinching the skin for about 3 seconds. When let go, it should snap back into place within a couple of seconds, she adds.
That’s because skin retains water — a factor in its turgor, or ability to change shape and return to normal.
If skin becomes less elastic, “it can be a way to tell if you’re dehydrated, but it’s not foolproof … (and) isn’t helpful for everyone,” Cassetty tells TODAY.com.
“One issue with this test is that older people have less elastic skin, so when pinched, it remains tented for a more extended period of time. This doesn’t necessarily indicate dehydration.”
The skin pinch test is not as reliable in children, either, she notes. Other conditions that may cause poor skin turgor include dysautonomia — a dysfunction of the autonomic nervous system that affects about 70% of people with long COVID-19 — in which patients may have low blood volume, a factor in skin elasticity, Cassetty says.
Per the National Library of Medicine, a “lack of skin turgor” can be a sign of “moderate to severe fluid loss.” Mild dehydration is defined as fluid loss equal to 5% of body weight; moderate is 10% and severe is 15%.
How to tell if you're dehydrated
The skin pinch method is considered a “preliminary measure” to screen for dehydration, studies have noted.
It’s most commonly performed on the back of the hand, but that’s a rule of thumb, not necessarily a gold standard, Cassetty says. Skin on the lower arm or abdomen can also be checked, according to the National Library of Medicine.
Bottom line: Skin pinching can detect dehydration, but usually at a later stage, Cassetty says.
Another way to tell if you need more fluids is to check the color of your urine. “You want it to be pale yellow. If it’s darker yellow, it’s a sign to have a big glass of water,” she advises.
“If there’s a chance you’re even slightly dehydrated, it’s a good idea to drink more fluids," she says. "If you’re significantly dehydrated, you might benefit from an electrolyte drink designed to help you absorb and retain fluid better than drinking plain water.”
