A video on TikTok showing how to test yourself for dehydration has been widely shared over the last few days, causing people to believe that they are lacking fluids.
The test, according to the video, is simple. Take your hand, place it in front of you and pinch the skin on your knuckles.
"To see how dehydrated you are you have to squeeze your fingertip right [on the knuckle], and if it goes back down, you're hydrated," the video claims. "If you squeeze it and it goes up like this, you're dehydrated."
So, will this test tell you if you're dehydrated? No. Well, not in the body location that the video says. The skin pinch test (or skin turgor test, if you want to sound more doctory) is used by physicians as a quick check for dehydration.
"The more hydrated you are, the more elastic your skin will be and it'll bounce back immediately after pinching it," Dr Karan Raj explained in an Instagram video, fact-checking the initial viral video above. If you're dehydrated the skin loses elasticity and it takes a while to return to normal and it's more likely to tent up."
However, doctors will generally not perform this test on the knuckles, for several reasons.
"The technique shown in this video isn’t quite accurate," Dr Raj wrote in a comment. "[You] should ideally pinch skin on back of the hand not the knuckles! Also the effect can vary depending on age too (less elastin as you grow older)."
The skin on your knuckles doesn't spring back that quickly when you're hydrated, especially in older patients with looser skin. Your physician is more likely to perform the test on the back of your hand (for an adult), lower arm, or abdomen for a child.
Lack of skin turgor (when your skin remains tented for too long) happens during moderate to severe dehydration, where you have lost 5–10 percent of your body weight through dehydration, so this isn't a test you should conduct on yourself merely to find out if you're getting enough water. It is for physicians to test whether medical intervention – such as putting you on a drip – is necessary.
Of course, there are several other ways to check if you're dehydrated. One is to check the color of your urine. Should it be a darker yellow than is normal, you are likely a little dehydrated. Feeling tired, dizzy, or if you are peeing fewer than four times a day are also good indicators.
If all of those sound too time-consuming, having a dry mouth or merely feeling thirsty is a pretty good indicator, too.