Japan is dangerously hot this summer, and dehydration can sneak up on you without warning, so stay safe with this easy tip.
Summer in Japan is almost always hot, but this year it’s on a whole other level. How hot is it? It’s hot to cook a meal on the roof of your car, and also hot enough that one man figured he’d go without clothes for the day as a last-ditch effort to stay cool.
But it’s not just laughably hot, but dangerously so. In these conditions, the threat of heat stroke is something you have to be aware of, especially if you’re in Japan on vacation and not acclimated to the weather. What’s worse is that the signs of dehydration can be easy to miss if you’re swept up in the excitement of your visit to Japan, and often by the time symptoms become severe enough to really grab your attention, there’re at the point where they pose a significant health risk.
So to help you avoid having to spend a day laid out recovering in your hotel room (or the hospital), Japanese Twitter user and nurse @snow_belltree has an incredibly simple self-check that literally takes only a few seconds to alert you that you’re suffering from dehydration.
今日、脱水になっていないかスタッフ全員、上司にチェックされた
— ⛩ユキ⛓️ (@snow_belltree) July 18, 2018
手背を軽くつまみ2秒以内に元に戻らないと脱水状態の可能性
今日は3人アウトでした
上司「忙しくても何度でも何度でも水分取って!トイレに行く回数が少ないのもあかんよ!」 pic.twitter.com/QwPnJTZrKp
All you have to do is:
1. Lightly pinch the skin on the back of your hand.
2. Let go.
3. Count how long it takes for the pinched area to return to its normal appearance.
That’s it. According to @snow_belltree, the skin’s turgor, or elastic resilience, is a good indicator of your hydration level, and if it takes more than two seconds for your skin to recover, that’s a sign that your body is becoming dried out, and you should get out of the sun and rehydrate as soon as possible.
As an example of how dehydration can sneak up on people, @snow_belltree says that her hospital’s head nurse recently performed spot checks on the facility’s employees, who, as medical professionals, you’d expect to be especially attuned to the need to stay hydrated in periods of intense heat. Nevertheless, three employees failed the skin pinch test, including a nurse and the hospital’s director.
@snow_belltree goes on to remind us that this is just one possible symptom of dehydration, and that even if your skin returns to normal in under two seconds, there’s still a chance that you’re becoming dehydrated, so listening to your body (especially if it’s telling you it needs fluids and shade) is always the most important thing to do. Still, with its easily measurable criteria, the skin pinch test provides easier-to-understand results than subjective dehydration symptoms such as “dry mouth” or “heavy sweating,” so it’s something to try periodically this summer as you explore Japan (a country in which, remember, you’re almost never far from a vending machine or convenience store stocked with cold drinks).
Source: Twitter/@snow_belltree via Jin
Follow Casey on Twitter, where he could really go for a Pocari Sweat right about now.

Komachi Shokudo: Japanese mum’s-style cooking for breakfast, lunch and dinner in Tokyo
Virtual idol Hatsune Miku redesigned with look that adds new elements and brings back old ones
Sushi Push Pops aiming to be Japan’s newest sakura season snack sensation
The top 10 graduation songs in Japan as chosen by current Japanese high school students
Starbucks Japan opens new Kyoto store in Place of Scenic Beauty
Komachi Shokudo: Japanese mum’s-style cooking for breakfast, lunch and dinner in Tokyo
Virtual idol Hatsune Miku redesigned with look that adds new elements and brings back old ones
Sushi Push Pops aiming to be Japan’s newest sakura season snack sensation
The top 10 graduation songs in Japan as chosen by current Japanese high school students
Starbucks Japan opens new Kyoto store in Place of Scenic Beauty
Say hello to Japan’s new generation of adults, fresh from Kitakyushu’s 2023 seijinshiki ceremony
Neo Shinjuku Atsushi: New cyberpunk restaurant bar serves post-apocalyptic food in Tokyo
Studio Ghibli releases Catbus pullback keychain that runs like the anime character
We followed Tokyo’s mystery walking map and ended up creating our own bar-hopping adventure
Häagen-Dazs Japan releases new ASMR ice cream called “Rocky Crunchy!”
Nine great places to see spring flowers in Japan, as chosen by travelers (with almost no sakura)
Starbucks Japan releases a new Cream Puff Frappuccino for a limited time
Starbucks Japan opens new cafe and art gallery in top Tokyo tourist neighbourhood
Is Japan’s Crab-shaped Cup Ramen Timer worth the hype?
Pizza Hut Japan teams up with creator of one of the country’s best kinds of ramen for ramen pizza
Starbucks Japan unveils new sakura cherry blossom collection for hanami season 2026
Silicone testicle covers banned from Japanese sauna following cups being left behind and on shelves
Japanese government planning higher ticket prices for foreign tourists at Tokyo National Museum
Pikachu and Eevee become handmade Lladró porcelain sculptures to celebrate Pokémon’s 30th birthday
Starbucks Japan releases new sakura goods and drinkware for cherry blossom season 2026
Super-salty pizza sends six kids to the hospital in Japan, linguistics blamed
Starbucks Japan unveils new sakura Frappuccino for cherry blossom season 2026
Foreign tourists in Japan will get free Shinkansen tickets to promote regional tourism
The 10 most annoying things foreign tourists do on Japanese trains, according to locals
Naruto and Converse team up for new line of shinobi sneakers[Photos]
Take a trip to Japan’s Dododo Land, the most irritating place on Earth
Survey asks foreign tourists what bothered them in Japan, more than half gave same answer
Japan’s human washing machines will go on sale to general public, demos to be held in Tokyo
Starbucks Japan releases new drinkware and goods for Valentine’s Day
We deeply regret going into this tunnel on our walk in the mountains of Japan
Studio Ghibli releases Kodama forest spirits from Princess Mononoke to light up your home
Japan’s newest Shinkansen has no seats…or passengers [Video]
Major Japanese hotel chain says reservations via overseas booking sites may not be valid
Put sesame oil in your coffee? Japanese maker says it’s the best way to start your day【Taste test】
No more using real katana for tourism activities, Japan’s National Police Agency says
Say hello to Japan’s new generation of adults, fresh from Kitakyushu’s 2023 seijinshiki ceremony
Neo Shinjuku Atsushi: New cyberpunk restaurant bar serves post-apocalyptic food in Tokyo
Studio Ghibli releases Catbus pullback keychain that runs like the anime character
We followed Tokyo’s mystery walking map and ended up creating our own bar-hopping adventure
Häagen-Dazs Japan releases new ASMR ice cream called “Rocky Crunchy!”
Pizza Hut Japan teams up with creator of one of the country’s best kinds of ramen for ramen pizza
Japanese manhole covers become a hit with foreign tourists in off-the-beaten path Tokyo area
13 surprising Japanese translations of American movie titles
Starbucks Japan opens new cafe and art gallery in top Tokyo tourist neighbourhood
Man in Japan falls into hole with a bear in it
23 flavors, five top recommendations for the wide world of Kikkoman soy milk【Taste test】
Furious train otaku in Japan confront foreign bicyclist after he gets in the way of their cameras