People wearing face masks walk in a street of Lyon, France. Chronic stress, the unrelenting kind many have experienced during COVID-19 pandemic, accelerates the rate of aging, according to researchers who study the biological impact of stress.JEFF PACHOUD/AFP/Getty Images
Your joints feel creakier. Your hair looks markedly greyer. The bags under your eyes seem to have become permanent fixtures.
You’re not just imagining it: The stress of the pandemic may have aged you prematurely.
Chronic stress, the unrelenting kind many have experienced during the past 16 months of grief, isolation, juggling work and child care, and anxiety about our security and our loved ones, accelerates the rate of aging, according to researchers who study the biological impact of stress. So does traumatic stress, the type that arises in life-threatening situations, like falling ill with COVID-19 or someone close to you getting sick.
Stress wears on your body, it hampers its ability to repair itself, and the effects go beyond what you feel or see in the mirror. It can take years off your life.
The good news is you can slow and perhaps, to some extent, turn back the clock, researchers say. Healthy habits, like eating and sleeping well, and especially physical activity, help mitigate the aging effects of stress.
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If you haven’t been doing these things already, now is the time, says Aoife O’Donovan, associate professor of psychiatry and behavioural sciences at the University of California, San Francisco.
“When those stressors are chronic as they have been, or when we fail to resolve or recover from them, that’s when the real negative impact, or the real harm, can be felt,” she said.
Some of the best evidence that chronic and traumatic stress speed up aging comes from research on telomeres, the caps at the ends of chromosomes that protect DNA from damage, Dr. O’Donovan explains. Telomeres naturally shorten with each cycle of cell division, and when they shorten to a critical length, the cell undergoes apoptosis, a form of cell death. Telomeres also shorten when inflammation and oxidative stress, a process tied to aging, are activated under psychological stress, she says.
Dr. O’Donovan’s research focuses on inflammation, which is part of the body’s immune response. Inflammation helps protect us from infection, but it’s also toxic to cells throughout the body, and it causes cells to turn over, or replace old ones with new ones, she says. When cells turn over, telomeres can shorten and become prematurely old.
Sometimes, rather than undergoing apoptosis when telomeres become critically short, cells stick around and release proteins that further promote inflammation, she says. That leads to more of these aged cells, which live on despite no longer functioning properly.
Inflammation is also part of a vicious cycle that makes your brain even more sensitive and alert to threatening information, she says.
“Stress really does beget stress,” she says, which is why it’s important to stop what she calls the “threat spiral” before further harm is done.
In studying military veterans who served in Iraq and Afghanistan, Dr. O’Donovan found those who experienced trauma and had post-traumatic stress disorder or other psychiatric disorders, including anxiety and depression, had a higher-than-normal risk of developing major autoimmune disorders like rheumatoid arthritis, Crohn’s disease, and multiple sclerosis. Initially, she and her team hypothesized that psychological disorders were tied to biological and other immune system changes that increased the risk of these disorders. But they now believe psychological stress alters the immune system in ways that increase both the risk of psychological disorders and autoimmune disorders.
As Dr. O’Donovan explains, she used to think she was pursuing two separate lines of study: what stress does to physical health and what it does to mental health.
“Over time, we’ve come to realize it’s just one question,” she says.
Another way stress accelerates aging is behavioural. When people are stressed out, they tend to eat poorly, exercise less, sleep less well, and perhaps drink and smoke more.
Some of these behaviours may be beneficial for a time – after all, it feels good to indulge in chocolates and cheese or to have another glass of wine. But over the long-term, they can be detrimental and are difficult to change, says health psychologist Eli Puterman, an associate professor at the University of British Columbia’s school of kinesiology and Canada Research Chair in physical activity and health.
In research on rodents, consuming unhealthy foods while having elevated levels of the stress hormone cortisol has been shown to deposit more fat around the organs than eating unhealthy foods under no stress, Dr. Puterman says. A similar effect is thought to occur in humans. Unlike subcutaneous fat under the skin, this fat around the organs, called visceral fat, is associated with health problems including Type II diabetes and cardiovascular disease.
“We’re not just gaining weight during a pandemic because we’re all stressed out. But we’re also gaining weight, potentially, in the wrong areas of the body,” he says.
In his research before the pandemic, Dr. Puterman found maintaining healthy sleep habits, a healthy diet and an exercise regimen can buffer the aging effects of stress. In one study of family caregivers of individuals living with dementia, he and colleagues found participants who were given a gym membership and offered fitness coaching to get regular physical exercise were not only able to improve their fitness, the telomeres of their immune cells, obtained through blood samples, lengthened.
The researchers can’t claim exercise reverses aging. Dr. Puterman says the telomere lengthening could be explained by the fact that exercise clears out old cells, which are replaced by new ones. Exercise has also been shown to bring more of a white blood cell called B cells into the bloodstream. So it’s also possible that B cells, which have longer telomeres than other cells, increased the average length of telomeres the researchers were able to measure, he says.
Regardless, participants who were physically active felt better. They had lower levels of depression and stress, he says.
Dr. O’Donovan is also a proponent of physical activity, calling it “one of the most powerful ways we have of targeting inflammation.”
At Columbia University, psychobiologist Martin Picard has found that reducing stress levels may reverse at least one aspect of aging: grey hair.
Dr. Picard, an associate professor of behavioural medicine, studies mitochondria, also known as the powerhouse of cells. Stress hormones can damage mitochondria, which causes cells to age faster, he says. In hair follicles, he says, dysfunctional mitochondria can cause hair to lose colour.
Dr. Picard zoomed in on individual strands of human hair to look at why some turn grey more quickly than others.
Volunteers provided hairs that were two different colours. Dr. Picard and his team analyzed them by turning their pigmentation into a mathematical pattern, which allowed them to quantify the colours. They then asked volunteers to think back to their most stressful events over the past 12 months, the equivalent of 12 centimetres of hair growth. The researchers were able to see that participants’ hair colour loss coincided with stressful events like relationship breakups, moving across the country, or having surgery.
But in some samples, white hair turned dark again, coinciding with times of lower stress for participants, such as a two-week vacation.
This suggests the aging process isn’t as fixed as previously thought, Dr. Picard says, providing hope to those feeling older than their years during the pandemic. “Human aging is not so linear and irreversible, and it’s actually modifiable.”
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