Stress accelerates aging, but there are ways to reverse the process

After an illness, a pregnancy or three days of partying, you may have the feeling of having suddenly aged. Although chronological age (how long you’ve existed) increases progressively over time, there’s evidence to show that it doesn’t always correspond to biological age (how old your cells are). Illness, smoking or exercise can influence how the years affect the body.

Today, a study published in the journal Cell Metabolism notes that stressful situations for the body — such as undergoing surgery, having Covid or being pregnant — accelerate the rate of aging. The good news is that this extra damage is reversible. In many cases, the cause of the accelerated aging can be reversed in only a matter of months, or even days.

To study how aging fluctuates, an international team of scientists from some of the most prestigious institutions used what are known as DNA methylation clocks to measure changes in the biological age of humans and mice, who were subjected to extreme stress. These measures of biological aging observe how small molecules accumulate in the DNA and change the way in which genes are expressed — the basis of what is known as epigenetics.

One of the experiments used a method to rejuvenate old mice known as heterochronous parabiosis. This technical name refers to a surgical procedure in which two mice — one young and one old — are joined together via surgery, so that they share a circulatory system. Many studies have found that this form of exposure to young blood rejuvenates the old mouse. In the case of the research that was published last Friday, rodents between the ages of three and 20 months were joined for two months. The researchers observed that the intervention suddenly increased the biological age of the younger mice, but that the sudden aging was reversed after only two months of recovery.

The authors took similar measurements in humans, looking at women after pregnancy, people who had suffered severe Covid, or had undergone major surgery. In all cases, rapid and significant increases in biological age were detected, but it was also observed that, after a period of recovery, the patients returned to the normal aging path. In addition to the natural recovery process itself, it was found that anti-inflammatory drugs — such as tocilizumab — accelerated the recovery of normal biological age. The authors suggest that this type of technique could be used to better assess the effectiveness of some drugs, particularly those aimed at slowing down aging.

The publication also notes some differences that will require further study to understand. For example, people who had elective surgery did not suddenly age as did those who had emergency surgery. On the one hand, it’s suggested that people who are preparing for surgery take preventive measures that slow down biological aging. Vadim Gladyshev — a professor at Harvard Medical School and one of the principal authors of the work — points out that “psychological factors” derived from experiencing an unexpected traumatic situation cannot be ruled out for causing the accelerated aging process. However, post-surgery, the patients recovered their initial biological age in less than a week.

Gladyshev says that these results make him think “that it’s possible to partially reduce the biological age of some cells, tissues, and possibly whole organisms.”

“Other studies show approaches capable of reducing the biological age during embryonic development, cell reprogramming and the exchange of material between old and young organisms,” he adds. Yet, he warns that “this is a very new area of research and all these approaches require validation.” The researcher believes that biological clocks can be useful for measuring physiological stress, the usefulness of some measures to alleviate it, as well as the impact of some drugs on aging.

Iñaki Martín-Subero — a researcher in the field of biomedical epigenetics in Barcelona — believes that “this work [paves the way forward]... although it must be expanded and replicated in the coming years.” According to the Spanish researcher (who did not participate in the study), this type of technique can help those who have an accelerated aging rate.

“There are studies that show very significant associations between having an accelerated clock and premature death from any cause, from cardiovascular diseases to cancer,” he points out. “These [epigenetic] clocks would allow for us to measure the effect of interventions, such as exercise, mindfulness or increased sleep — in some cases over a relatively short period — to slow down the biological clock and prolong life.” He himself is now testing the possibilities of reducing stress that accelerates aging, with measures such as mindfulness techniques.

The authors acknowledge that epigenetic clocks are still in the development phase and that — as they noted in their study — not all are able to capture accelerated (but reversible) aging. Nor has it been possible to determine the way in which a person ages and recovers from circumstantial stressful situations affects rapid or slow aging in the long term. In the coming years, however, it’s likely that this technology will become a tool to know how to deal with aging, which may not be as inevitable as once thought.

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