Have you ever heard how hot and humid it is in the recent Japanese summer season?
Fire and Disaster Management Agency of Japan reports,
95,710 people were taken to hospitals due to heatstroke or heat-related illness in 2018, 71,317 in 2019, and 64, 897 in 2020. The number of patients who are older than 65 years still has been increased every year.
Moving towards the 2021 Tokyo Olympics and 2025 Osaka World Expo, and also for preparation for the recent increase of tourists from overseas, the Japanese government and sightseeing organization prompt cautions of Japanese extreme hot and humid summer for especially foreign tourists.
Fatal summer heatwaves in Japan are becoming common in recent years, so you should warn yourself of heat-related diseases and heatstrokes if you want to travel to Japan.
- What Is Heatstroke?
- The Symptoms Of Heatstroke
- The Heatstroke Prevention
- 9 Tip For Heatstroke Prevention
- Drink Plenty Of Water (or Sports Drinks or *Barley Tea ) Frequently
- Wear Effective Outfits In Prevention Heatstroke
- Use The UV Protection Umbrella
- Avoid Outside Activities During The Hottest Part Of A Day
- Check The Weather And Information Before Starting A Day
- Take A Rest Immediately In A Cool Place
- Improve Your Health
- Heatstroke In Children And Elders
- Under COVID-19 Regulations
- 9 Tip For Heatstroke Prevention
- First Aid Of Heatstroke
- The Bottom Line
What Is Heatstroke?
Heatstroke, heat exhaustion is a condition caused by your body overheating, which is most likely occur in which your body cooling system can’t regulate body temperature due to the hot and humid environment.
In the worst case when the body temperature reaches 40 Celsius (105 Fahrenheit) and higher, emergency treatment will be required. If the treatment is delayed, it will be increasing your risk of serious complications or death.
Heatstroke occurs likely from July to August every year in Japan. Especially in July right after the rainy season and the temperature rapidly gets higher, the number of emergency cases of heatstroke increases.
Our body expands blood vessels to radiate heat from the body and sweats to evaporate to prevent a rapid rise in body temperature. However, when the weather is very hot and humid, the body heat is not dissipated, the sweat does not evaporate.
Heatstroke can be caused by the lack of body temperature regulation function and the imbalance of water and sodium levels in the body.
During the summer in Japan, average temperatures exceed 30 degrees Celsius all the time, not one day. Not only is the temperature high, but the humidity also is high, the sunlight is strong, and the wind is not strong. In particular, please note that small children, the elderly, those who are in poor physical condition, those who are obese, and those who do not exercise normally are prone to heatstroke.
The Symptoms Of Heatstroke
- Muscle cramps
- Abdominal cramps
- Heavy sweat or a lack of sweat
- Abnormal skin condition
- Mental confusion
The Heatstroke Prevention
Anyone has a risk of heatstroke, at any time, and in any location under a heat and humid environment.
You can’t be relieved even when you are indoors.
National Institute for Environmental Studies in Japan reports 76% of patients in 23 wards of Tokyo who lost their lives in 2018 became heatstroke indoors. Indeed, the number of cases that heatstroke occurred inside of the building has been increased every year since 2017.
There are reports that international visitors were required emergency treatments during their trip due to heat-related illness.
If you don’t get used to a sticky humid hot climate, (even the Japanese haven’t get used to it obviously,) you have a risk of heatstroke more.
So, what you can do to prevent heatstroke during traveling in Japan?
9 Tip For Heatstroke Prevention
Drink Plenty Of Water (or Sports Drinks or *Barley Tea ) Frequently
If you sweat a lot due to activities exceed 30 minutes indoors or outdoors in hot and humid weather, you will be deprived of sodium and minerals as well as water in your body. Hydration is the basic prevention for heat stroke, instead of just hydrating, intake sodium is also important to replenish with it.
Rehydration with water-only can impact the balance of sodium level and mineral concentration in your body, which will cause various symptoms of heatstroke. Sports drinks contain well-balanced sodium and minerals to replenish energy is more effective because it improves the absorption of water and sodium and also helps to recover from fatigue. Avoid drinks containing caffeine as they have a strong diuretic effect.
Barley tea is also recommended for hydration, which is expected to prevent heatstroke in Japan. It doesn’t contain sodium but adding a pinch of salt can help as well.
*Why Barley Tea is good for prevention from heat stroke?
Wear Effective Outfits In Prevention Heatstroke
It is also important to consider your outfits to choose one that reduces the risk of heatstroke by materials that allow the body heat to escape easily and by using summer accessories. The effective materials in preventing heat stroke have “water absorption (or hygroscopicity)” that absorbs sweat and “quick-drying” that dries out sweat quickly such as Cotton, Silk, Linen, Nylon, polyester, Rayon.
Also, check out outfits that have good breathability. Fit tightly have poor breathability and the body heat will be hard to escape. Pack loose-fitting clothes for Japan’s summer vacation. The open neck and fluffy cuffs are better than the tight-fitting clothes to prevent heatstroke.
Use The UV Protection Umbrella
*According to the measurement by the Ministry of the Environment, the UV protection umbrella had a WBGT reduction effect of about 1 to 3 Celsius degrees.
In an artificial weather simulation room (30 ℃, humidity 50%, solar radiation 1.2kW/㎡, wind speed 0.5m /s), two 15-minute walkings were performed, with six men wearing only hats and UV protection umbrellas. The case of using 99% cut UV protection umbrellas has been confirmed that the amount of sweat is reduced by about 17%, and the effect of reducing human heat stress is also confirmed.
Therefore, the UV protection umbrella will be the must item to pack.
Avoid Outside Activities During The Hottest Part Of A Day
The heat peak is around 2 p.m. in July and August in Japan. but, the temperature starts to rise after 11 p.pm and the heat remains until around 5 p.m. Moreover, even September is still hot and humid in Japan due to climate change worldwide, you still need to be careful in September, and could be early October.
Check The Weather And Information Before Starting A Day
Check the weather forecast and related information such as the temperature, humidity, WBGT, and heat stroke index. In Japan, there is also a heatstroke alert on the weather forecast during the summer season. If you download applications such as “safety tip” and “Japan official Travel,” you will get the heatstroke alert as soon as possible.
If you want to download apps, read this post.
When you go out, check the weather forecast and the “heat index (*WBGT),” and decide on activities with a flexible itinerary.
Go to this site to check WBGT in Japan. https://www.wbgt.env.go.jp/en/
*The WetBulb Globe Temperature (WBGT) is a measure of the heat stress in direct sunlight, which takes into account: temperature, humidity, wind speed, sun angle, and cloud cover (solar radiation). (National Weather Service)
Take A Rest Immediately In A Cool Place
If you feel any change in your physical condition, moving to a cool place immediately is effective in preventing heatstroke. Move to a shaded or well-ventilated place, even outdoors.
Improve Your Health
Take body temperature regularly and check your health every morning. Knowing normal body temperature is the easy and quick way to know that you have a fever. Improve your health management for Japan’s summer vacation. When you feel sick, better to rest at a hotel.
The physical condition of the day affects the occurrence of heatstroke. Avoid outside activities under Japan’s hot summer weather with the condition such as too much drink alcohol the night before or skipping breakfast.
People who have a fever due to a cold, dehydration due to diarrhea, small children and the elderly, obese people, and people with impaired cardiopulmonary and renal functions are prone to heat-related illness, so it might be considered to traveling to Japan in the hot summer season.
Get Better Sleep
Also, it is important to get good sleep.
Note that the heat and humidity remain even nighttime in Japan. Indeed, there are many cases of heatstroke during the night.
Be sure the room is enough cool and use a dehumidification function if it’s available. A standard Japanese air conditioner has it.
Also, make sure your Airbnb has an air conditioner because there is a possibility some old houses and apartment houses don’t furnish it.
Heatstroke In Children And Elders
Children are affected by heat from the ground and are more susceptible to heatstroke than adults. If your child’s face turns red or sweats, it’s likely that their body is over-heated considerably, so rest them well in a cool place. To prevent heatstroke for your children, dress them effectively as I mentioned, and let them drink water frequently.
Older people have different sensations of heat and are less likely to sweat, which plays an important role in thermoregulatory function. Also, they are less thirsty, which can lead to heat-related illnesses.
Under COVID-19 Regulations
According to the Japanese government guideline,
Wearing a face mask in a hot and humid environment can increase the risk of heatstroke. For this reason, if you can keep the social distance (at least 2 meters/6.56 ft and more), take off the mask as a consideration for heatstroke.
When wearing a face mask, avoid hard activities, and hydrate frequently even if you are not thirsty. It is also necessary to take a rest keeping a social distance to take off the mask.
First Aid Of Heatstroke
Let’s talk about symptoms more when you have a heat stroke or heat-related illness. The Japanese Society of Emergency Medicine categorized into three levels of symptoms of heat stroke depending on the severity.
If heat exhaustion is untreated, it may progress to heatstroke. Urgent care is essential to save your life.
|The Severity Level|
|I||On-site First-aid is possible||Dizziness, fainting, muscle pain, |
muscle stiffness (leg cramps),
|II||Need to be transported to the hospital||Headache, mood discomfort, |
nausea, vomiting, fatigue
Need for hospitalization / intensive care
|Loss of consciousness, |
convulsions, inability to walk,
strange response to stimuli,
If you find a person who has any heatstroke symptoms, seek immediate medical help.
Call 119 (Not 911) or ask someone for help near you.
- Get the person into shade or indoors.
- Remove unnecessary clothing, and loosen a person’s belts, ties, and hooks.
- Cool the person down with whatever available — splashing water, blowing cool air, place ice packs, cold wet towels on the person’s head, neck, armpits, and groin.
Here is the guide about what to do in case you have emergency issues includes how to call an ambulance in Japan.
The Bottom Line
The summer season in Japan is beautiful and fun, and there are many things to do, such as traditional summer festivals and fireworks being held all over the country, and nature is brilliantly beautiful.
However, if you are concerned about yourself, your kids, and your family, you can also think about visiting Japan in other seasons to avoid crazy hot and humid summer.
Japan has four seasons,
- Spring (March-May)
- Summer ( June – Early September) * June, sometimes July has a rainy season.
- Fall (Mid September – November)
- Winter (December – February)
Spring and Fall seasons have comfortable weather and beautiful flowers and trees. The winter season is cold but you can enjoy spectacular winter scenery and comfort foods.
You can find out many interesting things to do in any season of Japan, but just be careful of dehydration, heat, and humidity if you travel in the Japanese summer.