If it is hot for a long time in summer, one or the other has to fight with sleep problems, dizziness and headache. In the worst case, there can even be a dangerous heat suspension. But in addition to such immediately noticeable consequences of heat, it also affects our body in the long term, as researchers have now found out. Accordingly, long periods of extreme heat can age people from 56 faster – some over a year.
We have to prepare for the fact that the summer in this country is getting hotter in terms of climate change. This also has consequences for our health. For example, in the event of extreme, long -lasting heat, our body’s cooling system can reach its limits, which means that circulatory problems such as dizziness and headache can occur. Older people and people with previous illnesses are particularly heavily burdened by the heat and, in the worst case, can even lead to death. A total of around 15,600 people died in the two heat summer 2018 and 2019 in Germany in the consequences of a heat load.
Are heat and early aging together?
But in addition to these immediate consequences, heat can also harm us in the long term, as Eunyoung Choi and Jennifer Ailshire from the University of Southern California have now found out. Specifically, the two researchers examined whether long periods of extreme heat can be used faster. To do this, they analyzed blood samples from over 3,600 representative-selected US adults aged over 56 years to possible epigenetic changes in the genome. These are chemical attachments on the DNA that influence the reading of the genes and that, unlike the genes themselves, can also be changed by external influences such as stress, illness, nutrition or temperature.
Because the individual pattern of these attachments, the so -called methylation of the DNA, changes in the course of life, it can also reveal the biological age of a person and their organs. This epigenetic age may differ from the chronological age based on the date of birth. Someone who is 45 years old, according to the birth certificate, can already have the body of a 48-year-old due to various diseases.
In their study, the researchers initially determined the biological age of the participants and then examined whether these people had experienced extreme heat in the six years before the blood was taken at their place of residence. Choi and Ailshire defined a heat day based on the so -called heat index, which also includes the humidity in addition to the pure temperature. This creates three stages, all of which were considered in the study as heat days: the “Caution” level includes heat index values of 27 to 32 degrees, “extreme caution” ranges from 32 to 39 degrees and “danger” of 39 to 51 degrees.
The more hot days, the higher the biological age
“Our results show significant relationships between more heat days and accelerated epigenetic aging, especially for long -term periods,” report the researchers. If the test subjects in the six years before the blood acceptance were exposed to many heat days, this even surprisingly had a surprisingly significant effect on their biological age, as Choi explains: “Participants who live in areas in which half of the year hot days with extreme caution or more (over 32 degrees), such as in Phoenix, Arizona, experienced up to 14 months of additional biological aging compared to those that in areas with less than ten Live in heat a year. ” This correlation remained even if other factors such as income, ethnicity and lifestyle were taken into account.
The connection between heat days and accelerated aging was even evident after relatively short periods of seven days or one to two months, as Choi and Ailshire found. However, the extent of premature aging was significantly lower than for longer periods. According to the researchers, this indicates that heat -related epigenetic changes occur relatively quickly and can accumulate over time.
Heat fueled inflammation
CHOI and AILSHIRE have not examined exactly how the heat leads to premature aging. But earlier studies on mice have shown that excessive heat leads to hypermethylation in DNA areas that are connected to stress reactions, skeletal muscles and the oppression of the immune system. Such changes can be fueled by the body’s inflammation reactions, which in turn accelerate aging.
“In addition, staying in an area with long -lasting heat can influence the psychosocial situation and the health behavior of a person who are closely related to aging. In this way, a persistent exposure to high temperatures can increase stress and unrest due to frequent sleep disorders and physical discomfort and reduce the general physical activity, which can contribute to faster health in old age, ”explain the researchers.
Better urban planning necessary
Since only older adults were examined in the study, it is still unclear how heat affects the aging of people below 56. Overall, however, it would not hurt if the architecture of the cities as a whole were optimized so that it better protects people from heat. In this context, for example, Ailshire floats more green areas and shade -giving elements. Such a redesign is essential, especially against the background of the advancing climate and demographic change. “When it gets warmer everywhere and the population ages and these people are susceptible, then we really have to deal with these protection strategies,” says Ailshire.
Source: Eunyoung Choi & Jennifer Ailshire (University of Southern California), Science Advances,
DOI: 10.1126/Sciadv.adr0616