The number of deaths due to heat stroke is increasing. Most of the ambulances are transported during the day, but more deaths occur at night, so we should be aware of the risk of heat stroke becoming more severe during sleep. We will explain the causes of heatstroke at night, the symptoms that appear as precursors, and effective preventive and countermeasure methods.
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Increase in deaths due to heat stroke… Be cautious of the severity of the late summer heat
These days, not a day goes by without news about COVID-19. In addition to that, as it gets hotter, the topic of heat stroke is gradually increasing. What is especially heartbreaking is that many people die from heatstroke. Since 2018, more than 100 people have died each year. I am very worried because we are expecting another hot summer this year.
It is important to take measures against the new coronavirus infection, but in the summer when you have to wear a mask, you also need to be careful about heatstroke. Failure to do so can not only make you sick, but it can also be life-threatening. Recently, it has been noticed that heatstroke occurs not only during the daytime but also at night.
Is the rate of aggravation higher at night? Risk of death due to heat stroke during sleep
According to the Tokyo Fire Department, 5,634 people were transported by ambulance due to heatstroke in 2019. Of these, 212 people were transported by ambulance between midnight and 6 am, which is about 4% of the total. Looking at this number alone, I think, “Heat strokes are more common during hot days, and not so at night.”
However, during the same period, the number of people who were determined to have died of heat stroke at the Tokyo Metropolitan Medical Examiner’s Office was 38 during the daytime and 40 at nighttime, which is higher at nighttime than during the daytime. . The fact that the number of fatalities is high compared to the low number of people transported by ambulance may indicate that heatstroke tends to become more severe at night.
Causes and tendencies of heatstroke during sleep: Temperature, bedroom environment, age, physical condition, etc. affect
Let’s take a look at the factors that make it easier to get heatstroke during sleep.
■Hot and humid daytime When the
temperature is high, we sweat to cool down. When the heat continues, you sweat a lot and your body loses water and salt. Even if the temperature is not too high, you still sweat a lot because sweat cannot evaporate when the humidity is high. If you sweat more than 2% of your body weight without replenishing water and salt, your ability to exercise and regulate your body temperature decreases.
It is necessary to be careful not only on days when the temperature is particularly high, but also when it suddenly becomes hot after a series of relatively cool days, or when the heat continues for many days. When your body is not accustomed to the heat, or when the heat continues and you lose your physical strength, you are more likely to get heatstroke. Even though you have symptoms of heat stroke during the day, if you take it lightly and say, “Well, it’s okay,” the heat stroke may get worse during sleep, when you can’t rehydrate.
■The heat and humidity continues even at night
Many people find it difficult to sleep on tropical nights when the temperature exceeds 25 degrees Celsius. I feel sleepy when my body temperature drops, but I can’t sleep well on tropical nights because my body temperature doesn’t drop well.
The sensible temperature is related not only to air temperature, but also to radiant heat. Radiant heat is the heat emitted from the walls, ceiling, and floor of the bedroom. Roofs and walls heated by sunlight during the day dissipate heat at night. When heat is dissipated in the room, the sleeping person feels hot and sweats.
It is said that we sweat more than 500mL in one night in summer. If you don’t replenish the fluids that you lose while you sleep before you fall asleep, you may become dehydrated or heat stroke while you sleep.
■ Bedroom environment without air conditioning
It may be hard to imagine now, but the Showa era often had “cold summers.” Some people going through this period say, “I can’t imagine using the air conditioner while I’m asleep.” Also, some people turn off the air conditioner when they go to sleep because they don’t like the wind from the air conditioner.
But now it’s time for the “hot weather”. In fact, there is also data that 85.2% of the people who died indoors due to heat stroke did not use the air conditioner. Air conditioning at night is a necessity to protect lives.
Elderly people account for 50% of emergency transportation and 80% of deaths due to heatstroke. There are three reasons why the elderly are more susceptible to heatstroke.
The first is that the reaction of the body’s sensors is becoming dull due to aging. Therefore, it is difficult to feel the heat and thirst, so cooling the room and drinking water tend to be delayed.
The second is that the elderly naturally have less water in their bodies. The amount of water in the body decreases with age. Water accounts for about 75% of body weight in newborns, about 70% in children, and about 60-65% in adults, but only 50-55% in the elderly. Therefore, compared to young people, elderly people are more likely to get sick if the amount of water in the body decreases even a little.
The third is that many people do not want to drink water at night. When I was younger, I slept soundly and rarely woke up during the night. After the age of 60, it becomes normal to wake up once or twice during sleep to go to the bathroom. Many people are reluctant to drink water because they believe that drinking water before bed will increase the number of trips to the bathroom.
■ Poor physical condition, lack of sleep, etc.
People who are in poor physical condition due to colds, etc., or those who are weak due to lack of sleep are more likely to get heatstroke. People who take diuretics (drugs that excrete water from the body as urine) to treat congestive heart failure or swollen legs can also suffer from dehydration and heatstroke if they do not drink enough water. .
Signs and tendencies of heatstroke at night: dizziness, lightheadedness, numbness, etc.
At the beginning of heatstroke, symptoms such as dizziness, lightheadedness, feeling sick, muscle spasms, and numbness in the limbs appear. This is because the blood vessels in your hands and feet open up to allow heat to escape from your body, reducing blood flow to your brain, internal organs, and muscles. If you have these early symptoms, drink plenty of water and salt before going to sleep. If the symptoms disappear, then don’t hesitate to go to the emergency room.
As heat stroke progresses, symptoms such as headache, nausea, and body fatigue appear. Disturbance of consciousness or convulsion that heat stroke becomes serious occur. If this happens, call an ambulance immediately.
How to prevent heat stroke during sleep … “Hydration” and “Keeping cool” are the basics
The basics of preventing heatstroke during sleep are hydration and cooling.
Drinking lots of fluids right before bed will increase the number of times you wake up with the need to go to the bathroom while you sleep. Therefore, drink enough water during the day and make up for the lack of water little by little after dinner. Depending on the temperature, humidity, and weight, the amount of water you should drink per day is about 1.2 to 2 liters. If you are thirsty or have early symptoms of heat stroke, be careful not to drink enough water.
Sleep well when the temperature in the bedroom is below 26 degrees. Turn on the air conditioner about 30 minutes before going to bed to cool the ceiling, walls, and floor. We recommend leaving the air conditioner on until morning. If you can sleep cool and sound, your physical strength will recover, so you can raise the temperature of the air conditioner a little during the day. Considering the electricity bill throughout the day, it is more profitable.
If the wind from the air conditioner hits your body directly, you may feel sluggish or catch a cold, so be careful of the direction of the wind. If you place a fan diagonally across the room and send air toward the air conditioner, the air in the room will flow and you can cool the room efficiently.
Dangerous heatstroke at night… “Take proper measures. Talk to the elderly.”
In the 21st century, summer is completely different than it used to be. Extremely hot days and tropical nights are now the norm. As a result, the number of people who get heatstroke at night and the number of people who die from heatstroke are increasing. Everyone, please change your way of thinking and take measures against heat stroke during sleep. Heat stroke not only makes you sick, but in severe cases it can even kill you.
Older people in particular tend to be late in noticing it, so young people have to be careful. If you know an elderly person who doesn’t drink enough water or turns off the air conditioner at night, please say something to them.