How to prevent heatstroke (sunstroke)

• First Aid
• How to Prevent Heatstroke
• Links
• In Case of Heatstroke（PDF）

Two major physiological changes occurring when we stay in an environment with a high temperature for a long time are the dilatation of skin blood vessel and sweating.. The former increases skin temperature via an increase in its blood flow and the latter increases the dissipation of the evaporation heat. Both contribute to keep our body temperature, especially those of internal organs, stable.

It must be noted that we may suffer from heatstroke even when we are in a shaded area such as a gym or classroom, or on a relatively cool day. Heatstroke occurs due to failures of the thermoregulation mechanisms above mentioned, but it is preventable as far as we have proper knowledge. Furthermore, it is good idea for us to know how to give first aid for patients suffering from heatstroke.

【First Aid】

Have the patient carried to cool and shaded area, elevate his/her feet, and hydrate with a “sports drink” or water which is rich in minerals, if they are available. If the patient has difficulty to drink due to nausea, or if the person exhibits symptoms such as confusion or coma, notify emergency services immediately. Cool the person’s body while waiting for the ambulance. Remove outer clothing, spray the body with water, or wrap in a wet towel. Place ice packs or a wet towel under armpits and around groin, neck and ankles, as these areas are close to large blood vessels. Massage hands and feet upward, toward the heart, to promote circulation. The key to lifesaving in case of heatstroke is to reduce body temperature.

How to Prevent Heatstroke

Light and Loose Clothes

Avoid dark-colored clothes which absorb the sun’s heat and get hotter and wear light-colored clothes, instead. Choosing loose fitting clothing and loosening ties are helpful to keep air circulation good.
A hut, a cap, and/or an umbrella are helpful to cut off sunlight. We can also do things like keeping the curtain closed, walking in shaded areas.

Hydration

Drink water regularly: don’t wait to become too thirsty. Although 53% of the body is consist of water, it becomes dehydrated when we lose　its just 2%. Taking 1000-2000ml of water a day is optimal. Since alcohol beverages causes dehydration because they promote urination. It is not appropriate to drink them for the purpose of hydration.

Enough Rest

Exhaustion is a common cause of heatstroke. For the prevention of heat stroke, enough rest is necessary.

Special cares for chronic diseases

Individuals suffering from cardiovascular diseases or diabetes should be especially careful for heatstroke, because they may have problems with thermoregulation. If you are administered with some medication, please ask the doctor if it causes dehydration..

Habituation to Heat

Humans are susceptible to rapid changes in temperature, so it mast be noted that we tend to have heatstroke in hot and humid weather, just after the rainy season.

Links (Japanese only)

Information about heatstroke (Ministry of the Environment)

This website offers the information about Wet Bulb Globe Temperature and the annual numbers of heatstroke victims.

How to Prevent Heatstroke (Japan Sports Organization )

This organization has an ongoing campaign to prevent heatstroke.

Prevention of Heatstroke in Offices (Ministry of Health Labor and Welfare)

The Ministry of Health Labor and Welfare urges countermeasures against heatstroke.