"Be Cautious if They Talk Less"—The Complete Guide to Overlooked Signs of Heatstroke in Children 2025

Table of Contents

1. Introduction

2. Reasons Why Children Are Prone to Heatstroke

3. Early Signs That Are Easy to Miss

4. Age-Specific Points of Caution

5. Risk and Countermeasures by Situation

6. Early Detection Checklist

7. Preventive Measures in Daily Life

8. Hydration Based on the Latest Guidelines

9. Technology Utilization Techniques

10. Emergency First Aid

11. Collaboration Among Parents, Schools, and Communities

12. Frequently Asked Q&A

13. Conclusion
    
    

1. Introduction

As of June 2025, emergency transport data from across Japan shows that the proportion of children transported for heatstroke in May and June accounts for nearly 20%, which is as high as in midsummer.newsdig.tbs.co.jp Children have immature body temperature regulation functions and a high water content ratio per body weight, making them more susceptible to dehydration, thus increasing the risk. This document comprehensively outlines the actions that parents and educational institutions should take based on the latest medical guidelines and government directives.cfa.go.jpjaam.jp

2. Reasons Why Children Are Prone to Heatstroke

2-1 Immaturity of Temperature Regulation Functions

Infants have underdeveloped sweating functions and fewer sweat glands, causing their core body temperature to rise rapidly. Additionally, their shorter height makes them more susceptible to the effects of radiant heat from the ground.

2-2 Differences in Water Retention Ability

Compared to adults, children have a higher body water content per body surface area, yet their immature kidney functions make it difficult to produce concentrated urine, leading to faster dehydration.who.int

3. Early Signs That Are Easy to Miss

One Point

• "Toilet frequency + conversation volume" are the easiest indicators to monitor at home.

• Set alerts for step count and heart rate abnormalities using a smartwatch or mobile app to improve accuracy.
  
  
  
  

4. Age-Specific Points of Caution

Infants (0-2 years)

The temperature reflected from the ground can exceed 40℃ in a stroller. Frequent lifting and moving to shaded areas are recommended.

Preschool Children (3-6 years)

They may not express thirst when engrossed in play. Teachers and guardians should ensure hydration by prompting every 30 minutes.

School Age (7-12 years)

Extended periods of club activities and outdoor play. It is recommended to stop activities if the WBGT value exceeds 28.wbgt.env.go.jp

5. Risk and Countermeasures by Situation

Commuting to and from School

• Use a mesh pad with ice packs on the back of the school bag.

• Implement a "morning hydration" rule by having them drink 1/3 of their water bottle immediately upon arriving at school.
  
  
  

Outdoor Activities & Club Activities

• Take a 10-minute break and cool the neck if the WBGT meter exceeds 28.

• Use a shock-absorbing helmet without removing the hat (for cycling clubs, etc.).
  
  
  

Indoors & In Vehicles

• Even if the room temperature is below 28°C, using only a fan is dangerous if humidity exceeds 70%. Use with air conditioning, aiming for a relative humidity of 50%.
  
  
  
  

6. Early Detection Checklist (Print and stick on the refrigerator)

1. Urination frequency — No urination for half a day / Dark urine color

2. Conversation volume — Few responses / Lack of expression

3. Skin — Sweating stops and becomes dry

4. Body temperature — 37.5°C or higher

5. Behavior — Staggering / Sitting down
   
   
   
   

7. Preventive Measures in Daily Life

• Drink a glass of water with a small amount of salt after waking up and before going to bed.

• Include miso soup or fruits in breakfast to balance electrolytes and carbohydrates.

• Habitualize "finding cool places" like a shade-seeking game.
  
  
  
  

8. Hydration Based on the Latest Guidelines

According to the 2024 revised guidelines of the Japanese Association for Acute Medicine, oral rehydration solutions (Na 40-50 mEq/L) are recommended for mild cases.jaam.jp Choose sports drinks with around 6% sugar content, and drink 150 mL 30 minutes before exercise, then 100 mL at 20-minute intervals.

9. Utilization of Technology

• WBGT Meter: Easily usable at schools and parks. Alerts parents via app integration.

• Smartwatch: Notifies when heart rate exceeds 120.

• Monitoring Service: Sends email notifications of abnormalities via home Wi-Fi temperature and humidity sensors.
  
  
  
  

10. Emergency First Aid

1. Move immediately to a cool place

2. Loosen clothing and cool the neck, armpits, and groin

3. If conscious and able to drink, provide small amounts of cold oral rehydration solution

4. If there is impaired consciousness or vomiting, request emergency assistance and transport to a medical facility
   
   
   
   

11. Collaboration between Parents, Schools, and Community

• Distribute the "Toilet Frequency Sticker Chart" via class communication and share it between home and classroom.

• PTA organizes a "Heatstroke Watch Team" to patrol school routes.

• Collaborate with local governments to open public facility lobbies as "cool shelters."
  
  
  
  

12. Frequently Asked Q&A

Q. Should the contents of the water bottle be barley tea or sports drink?
A. Barley tea is recommended for school, and a sports drink with about 40 mEq/L of sodium is recommended during exercise.

Q. Is it okay to turn off the air conditioner at night?
A. If the room temperature exceeds 26°C and humidity exceeds 50%, it is safer to keep it on. Control with temperature settings rather than a timer.

13. Summary

Small changes such as "fewer toilet visits" or "less talkative" are SOS signals from children. By collaborating among families, schools, and communities to thoroughly implement the four pillars of ① visualizing early signs, ② action restrictions based on WBGT, ③ appropriate hydration and salt intake, and ④ prompt first aid, heatstroke can be reliably prevented. Let's protect children this summer with the "power of awareness."

List of Reference Articles

• TBS NEWS DIG "What are the hard-to-notice signs of 'children's heatstroke'?" (2025-06-19) newsdig.tbs.co.jp

• Children and Families Agency "Let's all watch over and prevent 'children's heatstroke'!"」 cfa.go.jp

• Japanese Association for Acute Medicine 'Heatstroke Treatment Guidelines 2024' jaam.jp

• WHO "Heat and health" Fact Sheet (2024) who.int