We all deal with stress on a daily basis – that’s part of modern life.
But it’s the kind of stress we deal with that makes a difference.
Acute stress is your body’s reaction to an immediate threat, like meeting a bear on your weekend hike. This is commonly referred to as the “fight or flight” response. Once the threat has dissipated, your levels of stress hormones return to normal and there are no long-lasting effects.
Chronic stress, on the other hand, is a different story. A recent survey reports that 40% of adult Americas lie awake at night because of stress1. Things like a demanding job, loss of a loved one, or concern about finances can contribute to chronic stress.
Chronic stress increases levels of stress hormones and affects many brain functions, ultimately putting you at risk for many stress-related conditions. In fact, stress-related health complaints contribute to 90% of doctors’ visits2. This is because over time, elevated levels of the stress hormone cortisol can chip away at our physical, mental, and emotional health. Many of the chronic stress symptoms we experience are a direct result of changes in the brain.
Here are three ways stress changes your brain.
- Chronic stress can shrink your brain.
Unrelenting stress can measurably reduce the volume of your brain. This is because cortisol can kill, shrink, and stop the generation of new cells in the hippocampus3, the part of your brain that stores memories. The hippocampus is important for learning, regulating memory and emotions, and shutting off the stress response after a stressful event is over. Additionally, researchers have found that chronic stress can contribute to lost volume in the medial prefrontal cortex, a brain area associated with personality, cognition, and decision making. So, when chronic stress shrinks your brain, it negatively affects memory, decision making, and control of impulsive behavior3,4.
- Stress can kill brain cells.
Chronic stress can kill brain cells both directly and indirectly. First, ongoing stress can halt the production of new cells in the hippocampus and may affect the speed of communication between existing hippocampal cells. This is because excess cortisol creates a surplus of the neurotransmitter glutamate5. Even though glutamate in the brain is a good thing – it tells your brain cells when to fire – too much glutamate can lead to molecules called free radicals that attack brain cells6. Free radicals actually punch holes in brain cell walls, causing them to rupture and die.Chronic stress can also indirectly contribute to cell death as a result of bad habits we might engage in while seeking out stress-relieving activities. Things like eating junk food, drinking too much alcohol, or smoking cigarettes to relax all contribute to your free radical load, and can intensify brain cell death.
- Chronic stress changes neural networks.
High-level functions we associate with the brain, such as thinking, computing, and decision-making, result from densely packed nerve cell bodies called “gray matter”. But, gray matter is only half of the brain tissue in our head. “White matter” is comprised of a network of fibers that interconnect various gray matter brain regions. Under chronic stress, these white matter fibers become hardened7. This results in hyper-connected circuits and less efficient communication within the brain.
Although prolonged chronic stress wreaks havoc on your brain, moderate or “good stress”, like studying hard for an exam or training for a marathon, can build stronger brain circuitry and a more resilient brain. That’s the double-edged sword of neuroplasticity. Your brain changes structure and function throughout your lifespan, so you are either creating a brain that is resilient or very vulnerable to mental disease based on your daily choices and lifestyle.
Changes in the brain that result from chronic stress are not easy to detect without undergoing extensive neurological testing. So, how can you tell if you are experiencing negative effects of chronic stress? It’s all about listening to your body. Side effects of chronic stress can include:
- Excessive worry and fear
- Anger, irritability, and frustration
- Insomnia, nightmares, or disturbing dreams
- Forgetfulness, mental confusion
- Difficulty making decisions
- Impatience with self and others
- Depressed mood
Feel like stress is getting the best of you? Fret not, you can consciously make steps toward a mindset and behavior that will improve your brain health. Minimizing stress and protecting your brain against its negative effects is easier than one might think. Stress comes less from the events in your life and more from your thoughts – your automatic negative reaction that triggers the release of cortisol – about these events. Mind-body relaxation techniques like meditation, biofeedback and yoga can help alleviate stress8. You can increase levels of brain-boosting molecules by getting daily physical exercise, even walking is excellent! And, you can keep free radical damage at bay by eating antioxidant-rich foods like fruit, vegetables, dark chocolate, and green tea.
Stress can have a powerful influence on your brain. Be proactive and take control of your stress before it takes control of you!
1American Psychological Association (2016). Stress in America: The impact of discrimination. Stress in America™ Survey.2Salleh, MR (2008). Life Event, Stress and Illness. The Malaysian Journal of Medical Sciences:MJMS, 15(4), 9–18.
3Sapolsky RM, et al (1993). Stress, the aging brain, and the mechanisms of neuron death. New England Journal of Medicine, 329:1049.
4Yuen EY, et al (2011). Repeated Stress Causes Cognitive Impairment by Suppressing Glutamate Receptor Expression and Function in Prefrontal Cortex. Neuron 73(5):962-977.
5Bremner JD, et al (2006). Traumatic stress: effects on the brain. Dialogues in Clinical Neuroscience, 8(4), 445–461.
6Alekseenko AV, et al (2009). Glutamate induces formation of free radicals in rat brain synaptosomes. Biophysics, 54: 617.
7Chetty S, et al (2014). Stress and glucocorticoids promote oligodendrogenesis in the adult hippocampus. Molecular Psychiatry, 19:1275-83.
8Epel E. et al (2009). Can meditation slow rate of cellular aging? Cognitive stress, mindfulness, and telomeres. Annals of the New York Academy of Sciences, 1172:34–53
Morgan Ingemanson is a PhD Candidate at the University of California, Irvine studying neurobiology. She specializes in functional neuroimaging and has been investigating the use of robotic devices for rehabilitating motor function after stroke. She is interested in mapping CNS repair and developing therapeutic interventions for neurorecovery.