We get biologically old when our bodies are under stress, but when we recover, we get young again, according to a study that analyzed the DNA of people when they had emergency hip surgery, severe Covid-19 or were pregnant.
“This recovery shows that we have the machinery to be able to turn back the clock at least a little bit,” says james white at Duke University in North Carolina, who co-led the study Vadim Gladyshev at Harvard University.
We usually measure age by the number of birthdays – the so-called chronological age. But people can be biologically older or younger than their chronological age, such as whether or not they smoke. Enough Sleep,
To measure biological age, researchers have developed an “epigenetic clock” that analyzes patterns of markers on DNA called methyl groups that correlate with age.
White, Gladyshev and their colleagues used these clocks to assess the effect of three types of stressful events on biological age. In each case, they analyzed DNA from blood samples collected at multiple points from participants in previous studies.
In the first analysis, the team found that the biological age of nine people with an average age of 81 increased rapidly when they had emergency surgery to repair their broken hips, but returned to pre-surgery levels in the following weeks.
Next, the team measured the biological age of 29 people, with an average age of 60, while they were hospitalized with severe Covid-19 and were discharged. Female participants’ biological age fell after discharge, but not male participants’, possibly because Men take longer on average to fully recover From illness, White says.
Finally, the team compiled data from four studies that included more than 200 pregnant women, which are known to put stress on the body. Their biological age increased during pregnancy, but, by six weeks postpartum, it had dropped below levels seen in early pregnancy. No transgender men or non-binary people were included in this part of the study.
The researchers also used epigenetic clocks to measure the biological age of the mice before, during and after pregnancy and found similar patterns.
In another experiment, the team showed that young mice experienced a sudden increase in biological age when they were surgically joined to older mice so that blood from the older mice could flow into their own circulation. This was reversed after being surgically separated from the older mice.
The idea that biological aging is accelerated during stressful events, but reversed afterwards, is consistent with a previous study that found that graying of hair never occurs in people after recovering from psychologically stressful events such as marital separation. Sometimes they regain their original color.
however, luigi fontana The University of Sydney in Australia states that even though there may be short-term fluctuations in biological age, the overall trend still continues toward aging. “Your gray hair may get some color back, but it’s not going to go back to the hair you had at age 10,” he says.
Nevertheless, we now know that biological aging can be reversed at least slightly, raising the prospect of being able to develop therapeutics to further reverse this reversal, White says.