What to do if heat makes you feel unwell on your Japan trip

Heat illness refers to various symptoms that occur when heat stops the body from regulating its temperature properly. It is the condition called 「熱中症」 in Japan. It can happen not only under the sun but also while resting in a hot, humid room.

Watch out too if you're sweating a lot or your hands and feet feel weak. Don't diagnose yourself or decide you're fine based only on body temperature or whether you're sweating. Check whether the person is fully conscious, whether their responses and walking are normal, and whether they can drink on their own. If anything seems off, cool them down right away and ask for help.

Before leaving and before going out at your destination, check the announcement time, target dates, and areas. The heat index isn't the same number as the temperature in a weather app or your body temperature. Look at the value from a nearby observation point, but sunshine and wind where you're actually staying can differ from that point, so check your surroundings and how you feel too.

The general heat illness alert 「熱中症警戒アラート」 is issued when the day's highest WBGT at any point in the target area is forecast at 33 or above. This 33 doesn't mean an air temperature of 33℃. Heat illness can still occur depending on your condition, activity, and surroundings even without an alert.

The 「熱中症特別警戒アラート」 is a special alert that dangerously hot weather is expected across several areas and there's a risk of serious harm to health. Stay somewhere cool and check on the people with you too. If you're planning to go to an event, first check whether the organizer cancelled it or changed the date or venue before setting out.

On hot days, cut down on going outside at midday as much as you can. The Ministry of Health, Labour and Welfare also advises resting in the shade often and avoiding the heat. Indoors too, control the temperature with air conditioning and drink fluids often.

It's good to cut first the plans that involve long walks or queuing outdoors. After seeing one place, build in rest time at your accommodation or somewhere air-conditioned. Even if you move plans to the morning or evening, check the heat index and how you feel at that time before moving.

Children and older people need extra care because their ability to regulate body heat differs. Ask the people with you whether they feel very hot or unwell. If they're less energetic than usual or responding differently, stop the activity. If it's a long walk to somewhere to rest, it's better to shorten the plans.

A cooling shelter is an air-conditioned facility designated by the local government as a place to escape the heat; in Japanese it's called 「クーリングシェルター」. When a special heat illness alert is issued, they're supposed to open at set hours. The city or ward office of the area announces details like the available dates and hours.

Even if it's on the list, check separately whether you can enter now. Check the facility guide's available dates and hours, and when you arrive ask staff where you can rest. If you can already stay somewhere air-conditioned, you don't have to move to a cooling shelter.

Rather than walking far down hot roads to find a specific facility, ask for help nearby first. When consciousness or walking looks strange, or the person can't drink on their own, don't spend time searching for facilities — call 119 and cool the body down.

Going inside a room doesn't make the heat danger go away. Heat illness can happen indoors too, so control the temperature with air conditioning. If dizziness or a headache continues, get medical care. Call 119 if someone is unconscious or can't drink on their own.

If the air conditioning is broken or there's a power outage, ask staff whether there's somewhere cool to rest, whether you can move to another room, and when the air conditioning might work again. If you have to move to other accommodation, ask the accommodation and the company you booked with separately about change fees and conditions. Don't assume in advance that you can change rooms or cancel for free.

Even when you've evacuated because of an earthquake or similar, the shelter may have no air conditioning or it may be unusable in a power outage. If heat makes you feel unwell, tell staff right away and ask for help resting somewhere cool.

The Ministry of the Environment's first aid materials also advise resting and taking it easy after recovering. If nausea or vomiting keeps you from drinking water, or your condition gets worse, call 119.

While recovering, drop sightseeing that involves long walks or waiting outdoors, and first decide with the people with you where you can rest. Don't push yourself to travel while unwell just to catch a booked train or flight.

Once you're well enough to move, check separately whether the trains and buses from your accommodation to the station or airport are running and whether your booked flight is operating. Transport can still be stopped even after you feel better. If you need to change a booking, ask the operator, airline, or company you booked with about how to change it and what it costs. A heat alert doesn't mean every booking can be changed or cancelled for free.

Show people nearby 「救急車を呼んでください。」 — it means “Please call an ambulance.” Also tell them the name and location of the facility you're in. In an emergency, don't wait for a consultation in your language to connect — call 119 first.

The JNTO Japan Visitor Hotline helps foreign travellers in Japan who are struggling because of illness or a disaster. It's available 24 hours a day, every day, in Korean, English and Chinese. Within Japan call 050-3816-2787; from overseas call +81-50-3816-2787. If you need an ambulance, call 119 before this hotline.

If it's not an emergency and you need to find a hospital, choose your area and language in the JNTO medical institution search. Ask the hospital about consultation hours, whether they can explain things in the language you need, and whether you can be seen now. JNTO generally doesn't interpret between patients and hospitals or book appointments for you. Finding the information doesn't guarantee interpretation, treatment, or a booking.