Health and Wellness Articles

Category: Mental Wellness

The Effect of Stress on Memory

June 26, 2009

Stress has more impact on your life than you might realize, influencing your mind, body, and memory.

Stress gets to everyone, but it could have a bigger impact than you think.

The effects of stress

Stress can have devastating effects on our health and well-being, from the health of our cardiovascular and immune systems to our mental and cognitive fitness.

With the media constantly broadcasting that "stress kills," most of us know this. So here's a question for you: Why don't we give stress the respect it deserves? Why do we take it for granted, especially when managing stress is well within our control?

Why we ignore stress

On the one hand, we're all familiar with stress. We use the word often - "My daughter is so stressed!" - and most of us experience stress on a regular basis. Maybe it's because we talk about it so much that we don't take it as seriously as we should. Everyone has stress, so why should I worry about it?

I think there's a reason we take stress for granted: because stress is elusive and difficult to grasp. It's invisible. You can't see it or touch it, and therefore it's hard to believe it could actually harm you. Stress can also seem psychological - more mental than physical, right? And if stress is in the mind, how can it get into the body and brain? But psychological stress affects physical wellbeing.

Here's a common example: you're stuck in traffic. There's nothing physically threatening about this - it's certainly not the same as being chased by an angry bear. But it's frustrating and associated with thoughts like "I'm never going to get home in time to make dinner" or "I'm going to be late for work and make my boss angry again." These are just thoughts, but just like the bear, they can trigger a stress response, which is very much physical.

The effect of stress on your body

The stress response begins with the release of hormones called cortisol and noradrenaline. Cortisol increases blood glucose to provide energy, and, if the stress lasts, stores that energy in the form of fat in the arteries and abdomen. Noradrenaline - also known as norepinephrine - causes your heart to race and your blood pressure to rise. In the short term, increased blood pressure and glucose are good things, helping you react efficiently to a threat and get out of harm's way. But in the long run, these same hormones that evolved to help can begin to hurt instead.

The effect of stress on your brain

Your brain suffers under stress just as your body does. Cortisol, for example, though secreted from the adrenal gland, makes it back to portions of the brain that are critical to our ability to learn and remember. When these areas are overloaded with cortisol, memory function begins to shut down.

In some of my research, I've shown that giving a public speech - pretty stressful situation for all of us - elevates cortisol levels dramatically. This makes us forget lists of words and pictures of common objects, and also makes us susceptible to false memories - memories of things that never happened. Even more disturbingly, stress actually enhances memory for emotionally negative information. So stress doesn't just make you forgetful; it makes you forget some things and selectively remember the negative.

It's not just memories during stress that are affected. Under certain conditions, brain cells can be impaired as well. We used to think this was only the case if stress was long lasting, but new research suggests that cellular communication can be impaired after just a few hours of stress.

Why you need to understand stress

It's critical to understand that stress can have physical effects on you. Noradrenaline and cortisol can be secreted just by thinking stressful thoughts. Once elevated, they have an impact on both the body and the brain. Your health and memory suffers.

Next time you're stuck in traffic, count your breaths, turn on the radio, or listen to a book on tape. Whatever small efforts you make to control your stress, your body, brain, and memory will benefit.

About the author

Jessica Payne, Ph.D.

Dr. Payne holds appointments at Harvard Medical School and the Psychology Department at Harvard University, where she is currently a Harvard Mind, Brain and Behavior Research Fellow. Her research focuses on how stress and sleep influence human memory, emotion, and creativity. When not working, she can be found sleeping or engaging in low-stress activities such as traveling, cooking, and educating herself about wine.