Can you remember a stressful experience you had years ago with amazing clarity, but not what you had for dinner last night?
There’s a scientific reason!
Stress exposure directly impacts memory formation and retrieval. Sometimes, that’s helpful, and other times, not so much.
So, what do studies show about the relationship between stress and memory?
What Do Studies Show About the Relationship Between Stress and Memory?
Many studies explore how stress affects memory encoding and retrieval. The literature can appear contradictory.
To provide better clarity, I’ll break this topic down into three sections:
- How the timing of stress exposure affects memory formation and retrieval
- The body’s cortisol response
- Individual variation
How Does the Timing of Stress Exposure Affect Memory Formation and Retrieval?
We categorize stress into two groups: acute stress and chronic stress. Each triggers unique physiologic responses.
During acute stress (stress that occurs over the course of minutes or hours), memory is enhanced. According to the current theory, because your body’s cortisol levels spike during stress, brief spurts of cortisol enhance memory function.
This makes sense from an evolutionary perspective. Consider what caused stress in cavemen (stumbling upon a lion’s den, for example) and why it was important to remember that information (so they could avoid that den in the future).
Chronic stress (ongoing stress over days, weeks, months, or longer) is different. When endured at high levels over time, cortisol becomes a neurotoxin. Although it’s our own hormone, it can damage vital parts of the brain, including the hippocampus, the region responsible for memory formation and processing.
To put things simply, acute stress helps both memory encoding and retrieval, and chronic stress hurts both memory encoding and retrieval.
How Does the Body’s Cortisol Response Influence Memory?
The memory formation and retrieval process is multi-layered, leaving many opportunities for individual variations.
The first layer is our hormonal stress response. This includes the hypothalamic-pituitary-adrenal axis, which determines how much cortisol the body secretes.
The second layer is how our brains function, including the size of different parts of the brain, which varies tremendously. These size variations determine how the hormonal stress response signal reaches the brain and how strong it is when it gets there.
The third and final layer is individual traits and personal history. For example, someone who’s been clinically diagnosed with anxiety or depression has a cortisol response that’s more highly attuned to their memory. Also, someone who has a history of trauma or PTSD has a more intense stress response, which also impacts their memory.
These three layers combined create the potential for tremendous variation in the relationship between stress and memory. This means that the same stress level can impact each person differently.
Physiological Presentations of Stress Depend on the Individual More Than the External Stressor
It’s easy to believe that a high-stress situation, such as a shootout with the police, would trigger a more severe biological response than a lower-stress situation, like watching a horror movie. However, that’s not always the case.
An individual’s stress response depends on the physiological variations I explored above. Take a man with PTSD, for instance. Watching “Saving Private Ryan” may trigger flashbacks and an elevated heart rate, but if his wife suffers a sudden heart attack beside him, he may remain calm, cool, and collected as he administers life-saving care and calls for help.
In other words, the factor that most influences the way stress presents is not the external trigger of the stress — it’s the person experiencing the stress.
This makes studying stress’s effects on memory challenging.
How to Mitigate Stress’s Negative Effects on Memory
Regardless of your individual variations, you can limit and improve stress’s effect on your memory by making healthy lifestyle choices.
I’ll sound like a broken record, but here are the best ways to help reduce stress and maintain or improve your memory formation and retrieval:
- Exercise regularly
- Consume a healthy diet
- Avoid unhealthy substances
- Get proper sleep
- Socialize
Here’s why these recommendations are vital:
Exercise
Studies demonstrate that exercise reduces stress and improves cognitive function.
“Neuroplasticity” refers to the brain’s ability to change through growth and reorganization. We used to think that young people’s brains would create new connections between neurons, and those connections would mature as they became young adults and remain the same for life.
Now, we’re realizing this isn’t the case.
Given the right conditions, we may be able to create new neural pathways throughout our lives. One condition is exercise, a method for improving hippocampal function. Since the hippocampus is intimately involved in memory function, there is evidence that exercise can help improve memory.
Diet
Diet choices, including consuming healthy fats, can also improve memory.
Omega-3 fatty acids, found in fatty fish, flax seed, oil, and nuts, are an excellent source of healthy fats. Monounsaturated fats like olive, avocado, and various nut oils are also great.
Interestingly, fiber is also associated with improved memory function. We’ve come to understand that our gut microbiome affects almost every aspect of our health and that there’s a gut-brain connection. So, eating a bowl of oatmeal for breakfast might just help you ace that exam.
Unhealthy Substances
In case you needed another reason to avoid substances like nicotine and alcohol, studies demonstrate that they hurt memory formation and retrieval.
Caffeine, however, is not detrimental to memory. But using caffeine to compensate for poor sleep habits is like smacking a Band-Aid on top of a gaping wound.
Sleep
I’m always talking about the importance of sleep. Sleep is highly associated with memory function and stress reduction, which also improves memory.
So, try improving your sleep hygiene. It’ll improve your alertness more than that second pot of coffee.
Socialization
Decreased socialization and loneliness correlate with stress and an increased risk for dementia and impaired memory. Social interactions can help.
Therapy, such as cognitive behavioral therapy, can also reduce stress and improve memory function. So can mindfulness meditation.
Regarding Physical or Mental Illness
If you’ve been diagnosed with anxiety, depression, PTSD, or other mental or physical illnesses, talk with your doctor or seek other medical attention before making any changes to your routine, especially if you take medications.
Today’s Takeaways
We began this post by asking, “What do studies show about the relationship between stress and memory?” We’ve covered that and more:
- How stress can affect your memory
- How stress can affect your body
- How to address stress in a healthy way
If you need help managing your stress or have concerns about your memory function, reach out today. We’re here to help.
