Survey of 814 Parents: The 'Invisible Heatstroke Risk' in Children Playing Sports - Explained by Expert Dr. Hideki Taniguchi
A survey by Taisho Pharmaceutical reveals the reality of breakfast habits and heatstroke prevention for children in sports. Experts highlight the risks of skipping breakfast and the importance of proper hydration.
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- 📰 Published: June 1, 2026 at 11:00
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With the increasing severity of extreme heat in recent years, the risk of heatstroke among elementary, junior high, and high school students participating in sports during the summer has become a significant social issue. In this context, Taisho Pharmaceutical Co., Ltd. conducted a survey in April 2026 targeting 814 parents of students across Japan to understand their children's breakfast habits and heatstroke prevention measures on days they participate in sports.
The results showed that about 60% of parents (502 respondents) said they "always make sure their child eats breakfast" on sports days. Including those who said "almost always" (133 respondents), about 80% are conscious of breakfast on these days. However, responses such as "sometimes" (55), "not sure" (45), and "rarely" (31) indicate that breakfast habits vary by household.
Regarding concerns about heatstroke, the top five responses were: "no particular anxiety or concern" (216), "child does not hydrate frequently" (187), "child is sensitive to heat/prone to feeling unwell" (116), "child pushes themselves too hard" (109), and "child cannot eat a proper breakfast" (106).
A survey on the implementation of heatstroke prevention measures revealed that many parents do not thoroughly implement measures such as pre-cooling or ensuring children do not skip meals.
Only 527 out of 814 parents ensure "frequent hydration," and only 340 provide "ice slurries" (fluid-like ice drinks) for pre-cooling, which is recommended by the Ministry of Health, Labour and Welfare. Other measures included "ensuring a proper breakfast" (292), "not letting them push themselves when unwell" (255), "ensuring sufficient sleep" (246), and "providing sports drinks/oral rehydration solutions" or "providing salt" (241 each).
Heatstroke can happen to anyone, anytime, anywhere. Recognizing symptoms early can be a matter of life and death. Children, in particular, often struggle to communicate their physical condition or tend to push themselves, making proactive measures essential.
Dr. Hideki Taniguchi, an expert on heatstroke, explains the key points for preventing heatstroke in children.
[Supervision] Dr. Hideki Taniguchi, Director of the Patient Support Center and Head of the Nutrition Department at Saiseikai Yokohamashi Tobu Hospital.
An expert in anesthesia, intensive care, oral rehydration therapy, clinical nutrition, and perioperative fluid/nutrition management. He graduated from Fukushima Medical University in 1991. His doctoral thesis focused on "Research on preoperative fluid management using oral rehydration therapy." He authored "Protecting Lives from Heatstroke" (Hyogensha, May 2024) and other books. His new book, "The Science of Drinking Water to Protect Life," will be released on April 21, 2026.
Heatstroke is the failure of thermoregulation due to water and electrolyte imbalance.
Heatstroke is not just a physical ailment caused by "heat"; it occurs when the balance of water and electrolytes in the body is disrupted, causing the thermoregulatory function through sweating to fail. Normally, our bodies release heat through sweat to maintain a constant temperature. However, as dehydration and electrolyte deficiency progress, sweating fails, leading to heat retention.
Children are at higher risk than adults because, while they have a higher water content, their thermoregulatory and sweating functions are immature, and they struggle to judge when to hydrate. They are also more susceptible to environmental factors due to a larger body surface area relative to weight. Their insensible water loss is 2-3 times higher per body weight than adults, making them prone to dehydration.
About 60% of the human body is water, which is not just "water" but exists as blood and extracellular/intracellular fluid, transporting oxygen and nutrients, removing waste, and regulating temperature. When water and sodium are lost simultaneously through sweating, this balance is disrupted, affecting circulatory and neurological functions.
If this progresses, it leads to circulatory failure, organ stress, and even loss of consciousness, culminating in heatstroke.
Heatstroke prevention parents should be aware of.
It is important to eat breakfast, even if it's just a jelly drink.
Parents must understand the risk of "skipping breakfast." Skipping breakfast means starting the day in a state of mild dehydration and energy deficiency.
During sleep, a certain amount of water is lost through insensible water loss. Starting exercise without replenishing water, sugar, and electrolytes leads to rapid dehydration. A lack of electrolytes like sodium changes blood osmotic pressure, making it difficult for the body to retain water.
Furthermore, reduced blood volume lowers oxygen and nutrient supply to the brain and muscles, leading to decreased concentration, slower reaction times, and increased risks of falls or accidents.
It is crucial not to skip breakfast. Aim for a balance of water, electrolytes, carbohydrates, protein, and vitamins.
Nutrients to focus on in breakfast and examples of food:
Water: Water, miso soup, soup, milk, yogurt, fruits (watermelon, orange, etc.)
Electrolytes: Miso soup, pickled plums, pickles, salted rice balls, sports drinks.
Carbohydrates: Rice, bread, bananas, oranges, honey, jelly-type nutritional supplements.
Protein (BCAA, etc.): Chicken, pork, beef, fish (salmon, tuna), eggs, milk, yogurt, natto, tofu.
BCAA (branched-chain amino acids) are essential for muscle building and energy during exercise.
Vitamin B group: Pork, eggs, natto, brown rice, whole grain bread.
Citric acid: Lemon, orange, grapefruit, pickled plums.
Taurine: Fish, squid, octopus, shellfish.
Breakfast Menu Examples:
Japanese style: Rice (carbs), miso soup (water/electrolytes), grilled fish (protein/BCAA/taurine), egg or natto (protein/Vitamin B), fruit (citric acid/water).
Western style: Toast (carbs), milk or yogurt (water/protein/BCAA), egg or ham (protein), banana or orange (carbs/citric acid).
If you are busy or have no appetite: Jelly-type nutritional supplements are effective. Those labeled for "heatstroke prevention" are designed with appropriate sodium and sugar balances, making them effective for water retention and absorption.
Hydration during exercise.
Drinking a large amount of water at once is not efficient as the body will excrete it. It is important to hydrate in small amounts before, during, and after exercise.
During exercise, electrolytes and sugar are essential alongside water. Drinking only water can dilute blood electrolyte concentration, leading to "dilutional hyponatremia." Sugar is necessary for muscle energy and maintaining blood glucose levels.
In my "Drinking Water Science," I categorize hydration into "daily," "during exercise," and "during dehydration."
Daily, meals and water/tea are sufficient. During exercise, especially in hot environments, water/tea is insufficient. Electrolyte-containing drinks are recommended.
For light exercise, water or barley tea is fine, but for exercise over 30 minutes or in high temperatures, sports drinks are effective. If dehydration occurs, oral rehydration solutions are recommended.
Use ice slurries to cool body temperature.
Ice slurries, which contain fine ice particles, are increasingly used. Because they have a large surface area, they absorb more heat when melting, cooling the body more efficiently than regular cold drinks. If they contain electrolytes, they support both hydration and core temperature control.
Don't let your guard down after returning home!
Check if children are lethargic or have flushed faces after returning home, as there is a risk of "delayed heatstroke."
"Delayed heatstroke" occurs several hours to a day after exposure to heat. Symptoms include headache, fatigue, and nausea. If these occur, rest in a cool place, loosen clothing, and provide water and electrolytes slowly. If symptoms persist, seek medical attention immediately.
What sports instructors should manage.
Instructors must manage three aspects: environment, behavior, and physical condition.
Environment: Check the WBGT index and adjust practice intensity accordingly. Use shade and ventilation.
Behavior: Encourage hydration "before feeling thirsty." Use electrolyte/sugar-containing drinks, jellies, and ice slurries.
Physical condition: Observe for early signs like flushed faces, lethargy, or slow movement. Prioritize rest for those who are sleep-deprived or skipped breakfast.
Heatstroke prevention is about "preventing before it happens," not "responding after it happens."
The results showed that about 60% of parents (502 respondents) said they "always make sure their child eats breakfast" on sports days. Including those who said "almost always" (133 respondents), about 80% are conscious of breakfast on these days. However, responses such as "sometimes" (55), "not sure" (45), and "rarely" (31) indicate that breakfast habits vary by household.
Regarding concerns about heatstroke, the top five responses were: "no particular anxiety or concern" (216), "child does not hydrate frequently" (187), "child is sensitive to heat/prone to feeling unwell" (116), "child pushes themselves too hard" (109), and "child cannot eat a proper breakfast" (106).
A survey on the implementation of heatstroke prevention measures revealed that many parents do not thoroughly implement measures such as pre-cooling or ensuring children do not skip meals.
Only 527 out of 814 parents ensure "frequent hydration," and only 340 provide "ice slurries" (fluid-like ice drinks) for pre-cooling, which is recommended by the Ministry of Health, Labour and Welfare. Other measures included "ensuring a proper breakfast" (292), "not letting them push themselves when unwell" (255), "ensuring sufficient sleep" (246), and "providing sports drinks/oral rehydration solutions" or "providing salt" (241 each).
Heatstroke can happen to anyone, anytime, anywhere. Recognizing symptoms early can be a matter of life and death. Children, in particular, often struggle to communicate their physical condition or tend to push themselves, making proactive measures essential.
Dr. Hideki Taniguchi, an expert on heatstroke, explains the key points for preventing heatstroke in children.
[Supervision] Dr. Hideki Taniguchi, Director of the Patient Support Center and Head of the Nutrition Department at Saiseikai Yokohamashi Tobu Hospital.
An expert in anesthesia, intensive care, oral rehydration therapy, clinical nutrition, and perioperative fluid/nutrition management. He graduated from Fukushima Medical University in 1991. His doctoral thesis focused on "Research on preoperative fluid management using oral rehydration therapy." He authored "Protecting Lives from Heatstroke" (Hyogensha, May 2024) and other books. His new book, "The Science of Drinking Water to Protect Life," will be released on April 21, 2026.
Heatstroke is the failure of thermoregulation due to water and electrolyte imbalance.
Heatstroke is not just a physical ailment caused by "heat"; it occurs when the balance of water and electrolytes in the body is disrupted, causing the thermoregulatory function through sweating to fail. Normally, our bodies release heat through sweat to maintain a constant temperature. However, as dehydration and electrolyte deficiency progress, sweating fails, leading to heat retention.
Children are at higher risk than adults because, while they have a higher water content, their thermoregulatory and sweating functions are immature, and they struggle to judge when to hydrate. They are also more susceptible to environmental factors due to a larger body surface area relative to weight. Their insensible water loss is 2-3 times higher per body weight than adults, making them prone to dehydration.
About 60% of the human body is water, which is not just "water" but exists as blood and extracellular/intracellular fluid, transporting oxygen and nutrients, removing waste, and regulating temperature. When water and sodium are lost simultaneously through sweating, this balance is disrupted, affecting circulatory and neurological functions.
If this progresses, it leads to circulatory failure, organ stress, and even loss of consciousness, culminating in heatstroke.
Heatstroke prevention parents should be aware of.
It is important to eat breakfast, even if it's just a jelly drink.
Parents must understand the risk of "skipping breakfast." Skipping breakfast means starting the day in a state of mild dehydration and energy deficiency.
During sleep, a certain amount of water is lost through insensible water loss. Starting exercise without replenishing water, sugar, and electrolytes leads to rapid dehydration. A lack of electrolytes like sodium changes blood osmotic pressure, making it difficult for the body to retain water.
Furthermore, reduced blood volume lowers oxygen and nutrient supply to the brain and muscles, leading to decreased concentration, slower reaction times, and increased risks of falls or accidents.
It is crucial not to skip breakfast. Aim for a balance of water, electrolytes, carbohydrates, protein, and vitamins.
Nutrients to focus on in breakfast and examples of food:
Water: Water, miso soup, soup, milk, yogurt, fruits (watermelon, orange, etc.)
Electrolytes: Miso soup, pickled plums, pickles, salted rice balls, sports drinks.
Carbohydrates: Rice, bread, bananas, oranges, honey, jelly-type nutritional supplements.
Protein (BCAA, etc.): Chicken, pork, beef, fish (salmon, tuna), eggs, milk, yogurt, natto, tofu.
BCAA (branched-chain amino acids) are essential for muscle building and energy during exercise.
Vitamin B group: Pork, eggs, natto, brown rice, whole grain bread.
Citric acid: Lemon, orange, grapefruit, pickled plums.
Taurine: Fish, squid, octopus, shellfish.
Breakfast Menu Examples:
Japanese style: Rice (carbs), miso soup (water/electrolytes), grilled fish (protein/BCAA/taurine), egg or natto (protein/Vitamin B), fruit (citric acid/water).
Western style: Toast (carbs), milk or yogurt (water/protein/BCAA), egg or ham (protein), banana or orange (carbs/citric acid).
If you are busy or have no appetite: Jelly-type nutritional supplements are effective. Those labeled for "heatstroke prevention" are designed with appropriate sodium and sugar balances, making them effective for water retention and absorption.
Hydration during exercise.
Drinking a large amount of water at once is not efficient as the body will excrete it. It is important to hydrate in small amounts before, during, and after exercise.
During exercise, electrolytes and sugar are essential alongside water. Drinking only water can dilute blood electrolyte concentration, leading to "dilutional hyponatremia." Sugar is necessary for muscle energy and maintaining blood glucose levels.
In my "Drinking Water Science," I categorize hydration into "daily," "during exercise," and "during dehydration."
Daily, meals and water/tea are sufficient. During exercise, especially in hot environments, water/tea is insufficient. Electrolyte-containing drinks are recommended.
For light exercise, water or barley tea is fine, but for exercise over 30 minutes or in high temperatures, sports drinks are effective. If dehydration occurs, oral rehydration solutions are recommended.
Use ice slurries to cool body temperature.
Ice slurries, which contain fine ice particles, are increasingly used. Because they have a large surface area, they absorb more heat when melting, cooling the body more efficiently than regular cold drinks. If they contain electrolytes, they support both hydration and core temperature control.
Don't let your guard down after returning home!
Check if children are lethargic or have flushed faces after returning home, as there is a risk of "delayed heatstroke."
"Delayed heatstroke" occurs several hours to a day after exposure to heat. Symptoms include headache, fatigue, and nausea. If these occur, rest in a cool place, loosen clothing, and provide water and electrolytes slowly. If symptoms persist, seek medical attention immediately.
What sports instructors should manage.
Instructors must manage three aspects: environment, behavior, and physical condition.
Environment: Check the WBGT index and adjust practice intensity accordingly. Use shade and ventilation.
Behavior: Encourage hydration "before feeling thirsty." Use electrolyte/sugar-containing drinks, jellies, and ice slurries.
Physical condition: Observe for early signs like flushed faces, lethargy, or slow movement. Prioritize rest for those who are sleep-deprived or skipped breakfast.
Heatstroke prevention is about "preventing before it happens," not "responding after it happens."
FAQ
What should be prioritized for sports in Taiwan's hot and humid climate?
Due to high humidity, sweat evaporation is less efficient, making electrolyte replenishment alongside hydration critical.