Your brain on stress

Everyone can spot the telltale signs of stress – a racing heartbeat, sweaty palms, rapid breathing, anxiousness, irritability and rushed mistakes – but what happens in our brain and body when our stress response is activated?

That’s what Dr. Jaideep Bains, Senior Scientist and Director of UHN’s Krembil Research Institute, is trying to find out. By understanding the effects of stress on the brain, he hopes to develop behavioural and pharmacological therapies to help mitigate its effects. Here’s what he’s learned so far.

When you’re stressed out, your body releases hormones, including cortisol, which helps control your body’s metabolism and immune system. It also releases adrenaline, the hormone that triggers the fight-or-flight response. Internal struggles like writing an exam and external threats like sitting in an overcrowded room trigger different neural pathways and chemical responses, but the production of cortisol happens in both instances.

This is important, says Dr. Bains. “It’s not directly helping you respond to the threat in front you, but it is helping you recover from stress,” he says. It also affects different regions in the brain to help you react more effectively the next time.

Stress may feel uncomfortable, but it’s an important trait that helps us respond to challenges and maintain our internal homeostasis – our internal state.

“That’s why the stress response exists,” explains Dr. Bains. “Without it, we wouldn’t be able to deal with any kind of challenges in our environment.” While too much stress is bad, studies show there’s an optimal amount of stress that’s useful to every organism. “This idea has emerged that you want this kind of Goldilocks zone of stress in your life,” he says. “Little challenges that you need to overcome.”

Physiological conditions tend to impact individuals, but stress is an exception. It can trigger a response in others, says Dr. Bains. When we’re stressed, we send out signals that alert those around us and even bring them toward us.

“Others then gain information about what you may have experienced,” he explains. “Another individual doesn’t have to be exposed to a threat, but they benefit from your experience by learning about it.” Research has shown that stress can be transmitted in people through cues in our sweat. Others can tell the difference between “stress sweat” and “normal sweat.”

There may be no cure for stress, but researchers like Dr. Bains are exploring ways to treat disorders that are linked to stress, like depression and anxiety disorders. Neuromodulation, which involves stimulating areas of the brain from the outside using a focused ultrasound, is a promising approach.

The role social interactions can have in lowering the long-term impact of stress is another area of interest for researchers. There are also distinct gender differences, he notes. “The long-term consequences of stress on neural circuits can be erased by social interactions in females, but we don’t see that in males,” he says. “Still, if you can surround yourself with positive people, that’s probably a great thing.”

But the research Dr. Bains is most excited about? The potential to change different patterns in the brain. “The ability to modify neural circuits to set you up to better manage stress – that’s where the real hope lies,” he says.

A few minutes of mindful breathing daily can clear your mind and relax your body, says Dr. Kathryn Curtis, a clinical psychologist at the Comprehensive Integrated Pain Program at UHN. Studies show that mindfulness can benefit various neurological, cardiovascular and mental health conditions.

“Stress can impact pretty much every system and physiological process in the body,” she says. “If we can carve out even a few minutes a day to combat stress through different mind-body approaches, including mindfulness, then we can turn the tides of stress in our minds and our bodies.”