After the beginning of autumn, many people ignore a small thing that can really hurt your health if you don't do it right

This summer has reached a new high.

Although it is the beginning of autumn, the "autumn tiger" should not be underestimated. Judging from the trend, the high temperature will continue for a long time.

Image source: Moji Weather (Hangzhou)

We must not be careless about heatstroke prevention, especially the elderly and people with underlying diseases, who should be more careful about the damage of high temperatures to the body.

" Accelerator " of disease progression

We are often very resistant to the "cold", but don't care about the "heat" on the other side. We allow ourselves to stay in a high temperature environment, thinking that it will be fine as long as we don't get heatstroke.

In fact, the harm of high temperature to people is not limited to heatstroke. It can cause continuous and chronic damage to the human body and can be called an "accelerator" for the deterioration of diseases. For example, when a mobile phone is overheated, the parts wear out more and the battery life is shortened. The same is true for the human body.

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The human body is very sensitive to temperature and needs to maintain core body temperature at all times. When it is in a high temperature environment for a long time, it has to work very hard to stabilize its body temperature, which is followed by a series of reactions - heat stress .

Among the deaths caused by high temperatures each year, the most common cause is not heatstroke, but damage to the heart, lungs, kidneys, brain and other organs caused by heat stress.

A study analyzing the high temperature weather in Nanjing, China from 2007 to 2013 found that on the day after a heat wave* (generally refers to extremely high temperature weather lasting for several days), the total mortality rate increased by 24.6%, the cardiovascular mortality rate increased by 46.9%, the respiratory mortality rate increased by 32%, the stroke mortality rate increased by 51.3%, the ischemic heart disease mortality rate increased by 63.4%, and the chronic obstructive pulmonary disease mortality rate increased by 47.6%.

Hot and sad!

The first part to be affected is the heart, as high temperatures can accelerate the deterioration of cardiovascular conditions.

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All-cause cardiovascular disease is the leading cause of death during heat waves. When the body is exposed to high temperatures, the demands on the heart are greatly increased because the heart must pump blood harder and faster to speed up blood circulation and make full use of every inch of skin to dissipate body heat.

However, many elderly people have physical dysfunctions, and their hearts have difficulty obtaining enough oxygen to support the efforts required by high temperatures. Especially for people with existing heart disease, this is more likely to lead to insufficient oxygen consumption in the heart, which in turn induces myocardial ischemia, infarction, and ultimately heart failure.

This myocardial ischemia may be asymptomatic, and you may not feel obvious discomfort in your heart, but the damage has already been done.

Heat hurts your brain!

In high temperatures, the evaporation of body water is accelerated, causing the blood to concentrate and increase viscosity, making it more susceptible to blood clots; vascular function and blood distribution change, and blood flow to the brain decreases... All of the above factors will increase the risk of stroke!

The most important thing to pay attention to is when you sleep at night. A study analyzed data from 11,000 strokes over 15 years and found that high temperatures at night significantly increased the risk of stroke.

Image source: Reference [5]

If you fail to replenish water in time while sleeping and allow yourself to be exposed to high temperatures and dissipate heat through evaporation of water, your blood will become more viscous.

In addition, high temperatures at night can also worsen sleep quality and affect brain function. In addition to stroke, high temperatures can also increase the risk of a variety of neurological diseases.

Many people turn off the air conditioner when they go to bed, thinking that they won't feel hot when they fall asleep. You may not feel it, but your body cannot rest in order to maintain its body temperature.

It is important to sleep in a cool environment!

Heat hurts the lungs!

A meta-analysis of 54 studies in 20 countries found a significant association between heat waves and respiratory mortality , with respiratory diseases being the second leading cause of mortality and morbidity during heat waves, after cardiovascular disease.

High temperatures increase lung pressure, and people with underlying lung conditions (such as chronic obstructive pulmonary disease) are more vulnerable.

Chronic obstructive pulmonary disease, also known as COPD, has a prevalence rate of 13.7% among people over 40 years old in my country, or one in every seven people. But many people don't even know they have this disease, so don't take it lightly.

Heat damages the kidneys!

Heat stress can damage kidney function, and extreme high temperatures can lead to acute kidney injury. However, the effects of high temperatures on the kidneys are not limited to acute reactions, but can also be chronic and difficult to detect.

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As the climate warms, an epidemic of chronic kidney disease is emerging in Central America, with the main risk factor being heat-induced dehydration. People are beginning to realize that chronic dehydration is likely to cause permanent kidney damage.

Turn on the air conditioner and drink more water

As we age, our body's ability to sense temperature declines, and many elderly people really can't feel the heat, and don't like to turn on air conditioners or fans. But the damage that heat does to the body doesn't decrease at all.

Therefore, don't rely too much on your own subjective feelings, try to keep yourself in a cool environment and drink plenty of water. We have very good living conditions now, so don't let your body suffer for the so-called saving and health preservation. The body resists the high temperature, which saves the air conditioner and costs yourself, which is really not cost-effective.

If you are worried that air conditioning is uncomfortable and wastes electricity, the World Health Organization has a suggestion:

Set the air conditioner to 27 degrees Celsius and turn on the fan at the same time. This will reduce the actual perceived temperature to around 23 degrees and save 70% of electricity costs.

Image source: Reference [8]

Don't let your body help you fight the high temperature. Helping your body fight the high temperature is the real way to stay healthy!

References

[1]Chen, Kai et al. “Influence of heat wave definitions to the added effect of heat waves on daily mortality in Nanjing, China.” The Science of the total environment vol. 506-507 (2015): 18-25. doi:10.1016/j.scitotenv.2014.10.092

[2]Kazi DS, Katznelson E, Liu C, et al. Climate Change and Cardiovascular Health: A Systematic Review. JAMA Cardiol. Published online June 12, 2024. doi:10.1001/jamacardio.2024.1321

[3]Ebi, Kristie L et al. "Hot weather and heat extremes: health risks." Lancet (London, England) vol. 398,10301 (2021): 698-708. doi:10.1016/S0140-6736(21)01208-3

[4]Barry, Hadiatou et al. "The Effect of Heat Exposure on Myocardial Blood Flow and Cardiovascular Function." Annals of internal medicine vol. 177,7 (2024): 901-910. doi:10.7326/M24-3504

[5]Cheng He, Susanne Breitner, Siqi Zhang, Veronika Huber, Markus Naumann, Claudia Traidl-Hoffmann, Gertrud Hammel, Annette Peters, Michael Ertl, Alexandra Schneider, Nocturnal heat exposure and stroke risk, European Heart Journal, Volume 45, Issue 24, 21 June 2024, Pages 2158–2166,

[6]Cheng, Jian et al. "Cardiorespiratory effects of heatwaves: A systematic review and meta-analysis of global epidemiological evidence." Environmental research vol. 177 (2019): 108610. doi:10.1016/j.envres.2019.108610

[7] Guidelines for the diagnosis and treatment of chronic obstructive pulmonary disease (2021 revised edition)

[8]https://www.who.int/zh/news-room/fact-sheets/detail/climate-change-heat-and-health

[9]García-Trabanino, Ramón et al. "Heat stress, dehydration, and kidney function in sugarcane cutters in El Salvador--A cross-shift study of workers at risk of Mesoamerican nephropathy." Environmental research vol. 142 (2015): 746-55. doi:10.1016/j.envres.2015.07.007

[10]Roncal-Jimenez, C et al. “Mechanisms by Which Dehydration May Lead to Chronic Kidney Disease.” Annals of nutrition & metabolism vol. 66 Suppl 3 (2015): 10-3. doi:10.1159/000381239

Planning and production

Source: DingXiang Doctor (ID: DingXiangYiSheng)

Review | Wang Feiyu, attending physician of the cardiovascular department of the Air Force Hangzhou Sanatorium

Editor: Yinuo

Proofread by Xu Lai and Lin Lin

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