Few words in the English language evoke more negative emotions than stress. The mere mention of these six letters could trigger mental images of looming work deadlines, unpaid bills, exam pressure or tense family Christmases, to name just a few scenarios.
But what if I told you that stress can also be positive? That, just as it can harm us, it also plays a key role in strengthening our immune system, forging connections in our brains that improve mental performance and building the resilience we need to navigate through life’s vagaries .
This first came to light through the work of an American psychiatrist named Firdaus Dhabhar, then a researcher at Rockefeller University, New York, who was studying the connection between short-term stress and the immune system as other than fight or flight. answer In the mid-1990s, stress was almost unanimously considered bad for us, but for Dhabhar this was illogical. From a Darwinian perspective, the survival instincts of our animal ancestors would have been honed through repeated brushes with danger.
“It doesn’t make sense that stress is always a bad, harmful, negative entity,” he says. “The fight-or-flight stress response is essential for survival. A gazelle needs this response to escape the jaws and claws of a lion, just as a lion needs it to grab its food . Mother Nature gave us this answer to help us survive and thrive, not to kill us.”
Over the past 20 years, Dhabhar and others have shown that short-term bouts of stress can help us in the modern world. A Ted talk by Dhabhar, now a professor at the University of Miami, about the positive effects of stress has garnered 30,000 views on YouTube.
For example, the tension of an upcoming race helps prepare athletes’ cardiovascular and musculoskeletal systems for optimal performance, while surveys have even found that the stress of having to work alongside childcare means that fathers are likely to be more productive home workers than singletons.
Both physical stress and mild to moderate mental stress stimulate the production of chemicals in the blood called interleukins, activating the immune system and making it better able to fight infections, while stress can affect up to and the entire development of children before birth. Babies born to mothers who experienced mild daily stress during pregnancy had more advanced developmental skills at age two, compared to children born to mothers who had enjoyed a relatively relaxed, stress-free pregnancy.
There are also several ways to think about stress. In addition to the pressure and strain inflicted by life events, different forms of exercise can be seen as stressing the muscles, while various types of cognitive challenges can be considered stressing the mind.
Use it or lose it
In January 2017, French cyclist Robert Marchand made headlines by setting a new world age group record at a velodrome in Saint-Quentin-en-Yvelines. What was particularly remarkable about Marchand’s performance was that he had turned 105 a month earlier, and his efforts made him the first centenarian to demonstrate an improvement in cardiovascular health with age.
Exercise physiologists found that Marchand, who had taken up competitive cycling seriously in retirement at age 68, had an aerobic exercise capacity, the gold standard measure of cardiovascular fitness, comparable to men from 42 to 61, half a century younger than him. .
Scientists researching healthy aging now see it as an indicator of what might be possible if we continue to apply manageable stress to our muscles, blood vessels and heart as we age. But most humans aren’t like Marchand. Many of us become progressively inactive as we age, exacerbating the age-related changes already occurring. As a result, if our muscles are not stressed, their fibers slowly atrophy and we become progressively weaker. The interaction between the nervous system and muscles also becomes less efficient without regular use, slowing our reaction times and making us more vulnerable to falls.
Resistance exercise can help preserve muscle mass. Photograph: Rocketclips, Inc/Alamy
“A muscle that is not activated deteriorates very quickly in many ways,” says Casper Søndenbroe, a scientist at the University of Copenhagen who studies the human neuromuscular system. “Muscles need to have that stimulus to maintain balance. If you don’t have a strategy for the later parts of your life, when you get to your 70s or 80s you’re likely to have some limitations with daily life because the functionality isn’t there. “.
To illustrate this, Andy Philp, who directs the biology of aging program at Sydney’s Centenary Institute, explains that if an adult man spends five to seven days lying inactive in a hospital bed, he will lose approximately half a kilo of muscle mass. But the difference between a 30-year-old and an 80-year-old is that the younger person’s body can recover and regenerate lost muscle much faster.
A range of people between 100 and 118 showed similar cognitive abilities compared to the average 50 to 60-year-old.
Søndenbroe has found that some forms of exercise-related stress are better than others at preserving muscle mass in later life. While some age-related deterioration is inevitable, as Marchand demonstrated, it can be kept under control. One of the best ways to do this is through resistance-based training, which involves training your muscles with weights or bands. Cycling is also considered a form of resistance training. “We’ve shown many times that this increases muscle size and muscle strength, so it’s really effective,” says Søndenbroe.
Studies have also shown that people who stay active through sports or moderate exercise during middle age and beyond are also less vulnerable to muscle decline.
That’s why Søndenbroe wants to encourage people to do whatever type of exercise they like best. “The most important thing is that the best exercise is the one you actually do,” he says. “So if you don’t like running high-intensity intervals, you shouldn’t. Find something you enjoy.”
Cognitive reserve
Exercise doesn’t just stress your muscles: it’s also a workout for your central nervous system, and even your mind.
There is a two-way interaction between the muscles and the nerves that extend outside the spinal cord. When muscles contract, they send signals to motor neurons, the long, spindly cells that control movement, keeping them active and working efficiently. Increased blood flow helps clear tau proteins, associated with Alzheimer’s disease, from the brain and cerebrospinal fluid, as well as stimulating neurons to produce a chemical called brain-derived neurotrophic factor, which protects neighboring brain cells.
We know that our brain size shrinks at a rate of about 5% a decade after age 40, and the rate of decline increases once we’re over 70. However, this shrinkage slows in older people who they do regular aerobic exercise, forms of physical exercise. activities that get blood pumping through the body, such as walking, running, swimming and cycling, to the point that they have four years less brain aging.
Studies show that people in their 80s who play the piano can slow cognitive decline. Photograph: Erickson Stock/Alamy
Just as Marchand showed that physical decline and frailty do not always have to come with age, studies of centenarians and supercentenarians, those who live beyond the age of 110, have illustrated that related cognitive decline with age is not always inevitable. Joyce Shaffer, a psychiatrist and behavioral scientist at the University of Washington in Seattle, says a series of studies of cases between 100 and 118 demonstrated similar or even superior cognitive skills compared to the average between 50 and 60 years
Other research has revealed the importance of incorporating a significant amount of mental stimulation into your daily routine, for as long as possible. For example, people who work a normal work week in their 50s and 60s are thought to be more resistant to cognitive decline than those who retire early. While you can challenge yourself by continuing to work or volunteer part-time, or trying to learn a new skill in your eighties and nineties, it may seem unnecessarily stressful, this kind of activity can keep your brain young.
“We’ve seen that people who started taking piano lessons in their 80s saw an improvement in brain function,” says Shaffer. “Staying at work, or at least participating socially in an activity, has a very good impact on maintaining function. There was a project in Baltimore where retirees went back to schools to tutor private students from low-income backgrounds who didn’t have much, and they actually experienced improvements in cognition doing that.”
One reason for this is thought to be that brief, short-term stressful events stimulate the brain’s stem cells to proliferate into new nerve cells, resulting in improved mental performance.
We have evolved to be active and respond to different stimuli and if this is removed it accelerates negative processes Andy Philp, Centenary Institute, Sydney
Given the spiraling of dementia rates expected over the coming decades, interest in the connection between positive stress and health in later life will only increase. Teams of scientists around the world have plans to try to harness the beneficial properties of moderate stress in the medical field, for example, to improve healing and recovery after surgery. Researchers have shown that this can increase the safety and effectiveness of vaccines, while earlier this year a clinical trial by Guy’s & St Thomas’ Charity found that exercise can help improve effectiveness of chemotherapy, as well as denying some of the harmful impact it can have. have to…