The hormone that wrecks the most damage on your brain and like a domino effect, on your body, is cortisol. Cortisol is a steroid hormone. It’s made by your two adrenal glands, one each found on top of your kidneys. But cortisol isn’t a bad hormone. In fact, when cortisol is under control, it’s a life sustaining adrenal hormone, essential for your body’s homeostasis. It’s in charge of your body’s anti-inflammatory process, it manages your immune system, it regulates your blood pressure and it works with the hormone insulin to regulate your blood glucose levels. Frankly, it is essential for life.
But when it’s out of control, it’s a raging disaster.
When you read in articles that stress causes this or stress causes that, what people are actually referring to, for the most part, are the effects of cortisol running rampage through your body. Stress in a nutshell causes an increase in cortisol. But it’s chronic stress that we need to worry about. With chronic stress cortisol doesn’t get switched off. Unlike epinephrine (adrenaline) that surges quickly and then dissipates rapidly, cortisol is damaging for the very reason that it just doesn’t go away. It streams through your body all day long, making it just so dangerous.
Cortisol is the major player in this game of chronic stress. It’s responsible for weight gain, particularly increased abdominal fat, and it’s been implicated as the leading cause of osteoporosis, digestive problems, hormone imbalances, cancer, heart diseases and diabetes. And if that weren’t enough, it’s also responsible for adrenal fatigue, where you are physically exhausted but wired and unable to rest. Adrenal burnout affects your moods, elicits poor sleep and makes it difficult to concentrate or remember things. That’s just the start of the cocktail of dysfunction and damage that cortisol is capable of wrecking on your system.
So what is it that cortisol actually does that is so harmful to your brain?
Cortisol creates more of the neurotransmitter glutamate.
Glutamate is a problem because it creates free radicals – or unattached oxygen molecules. If you were to think of these free radicals as pumped up, gun toting, crazy lunatics, that’s essentially what they’re like inside your brain. They are revved up to do damage. They punch holes in the walls of your brain cells, rupturing them and ultimately causing their death. It’s hardly surprising then, as your brain cells lay dying, that your ability to remember, or think clearly becomes impaired.
But don’t reach for that packet of chips, bottle of wine or a cigarette to calm you down. Eating junk food, drinking alcohol and smoking simply contributes to your free radical load. It’s like arming the militia with additional weaponry; you’re just doing more damage to your brain.
Stress makes you forgetful and emotional.
Memory problems are often the first sign of stress. Can’t find your keys, forgot an important appointment…? Cortisol chronically affects the brain cells in the hippocampus, the area of the brain involved with memory, learning, and emotional regulation. When we are chronically stressed the electrical signals in the brain associated with memories weaken whilst the areas in the brain associated with emotions strengthen.
Stress makes your Amygdala larger.
As chronic stress continues it increases the size of the amygdala, an area in your brain associated with emotional activity, but mostly studied for its capacity to react to fear. Stress actually increases the physical size of the amygdala, its activity level and its number of neural connections. The larger the amygdala gets, the more intense your fear and anxiety becomes. It’s a vicious cycle.
Stress halts the production of new brain cells.
Whilst you might lose brain cells every day, you also make new ones. Brain-derived neurotrophic factor (BDNF) is a protein that your brain uses to keep your brain cells healthy and functioning at an optimum level. It also plays an integral part in the formation of new brain cells. Think of the protein we eat to build muscles, well BDNF is like that, but for brain cells.
Want to know what debilitates BDNF quicker than Mike Tyson in a boxing ring? Cortisol. High levels of cortisol inhibit BDNF production. Which means your brain cells have no protein to keep them growing strong, and it also means you’re missing one of the essential building blocks to making new brain cells. Lowered BDNF levels are associated with depression, OCD, dementia and other neurotropic diseases like Alzheimer’s.
Stress depletes critical brain chemicals.
Our brain cells use chemicals called neurotransmitters, to communicate with each other. You’ve heard of some of these neurotransmitters, they’re called serotonin and dopamine.
Serotonin is the chemical our brain produces that makes us feel happy. It also plays a large role in mood, learning, appetite control and sleep. Dopamine is the chemical that gives us our get up and go, it motivates us and gives us reason to get the job done.
Cortisol depletes serotonin and dopamine levels. It actually damages the receptor sites of these neurotransmitters.
Women who are low in serotonin are prone to depression and anxiety and interestingly, binge eating. Men are more inclined towards alcoholism, ADHD and impulse control issues.
When your brain is low in dopamine, which is in charge of your motivation, you’re left feeling unenthusiastic, unmotivated and lethargic. And you’ll find yourself reaching for artificial means to give you a bit of get up and go. Coffee’s a big one, as is reaching for a sugar hit to get you over the hump, alcohol to get you through the evening, and even illicit drug use.
Clinically speaking, serotonin based depression is usually accompanied by anxiety and irritability whilst dopamine based depression presents as lack of enjoying life and lethargy.
Chronic stress shrinks your brain.
Neuroscientists have measured that stress measurably shrinks your brain. Our old friend cortisol is lethal in its ability to destroy and harm existing brain cells, and it is rampant in stopping the production of new ones. But it also runs ruck shot over the prefrontal cortex (PFC). The PFC is the most evolved part of the brain. It’s in charge of all of our highest cognitive abilities. However, it’s also the most sensitive to stress. Even mild stress can cause a rapid deterioration in cognitive abilities and prolonged stress exposure will actually cause architectural changes in the prefrontal dendrites.
Dendrites are the small branches that come off the neuron, they are imperative for the electrochemical stimulation of the cell. That is, the dendrites enable the cell to go ‘online’. Essentially under stress, the prefrontal cortex goes ‘offline’. Imagine your ability to think, rationalise and determine strategies, from getting to the car to working out a weekly budget, simply ceasing up? Well that’s the sort of effect we’re looking at when the PFC gets affected by stress. Because of the reduction in synapse activity (due to the reduction in the dendrites) the neurons or brain cells in the PFC shrink.
Stress let’s toxins into your brain.
Your brain has a semi-permeable membrane that protects your brain from harmful substances, whilst at the same time letting nutrients in. When you are under prolonged stress, this filter becomes more permeable, letting in more pathogens, heavy metals and other toxins through your blood brain barrier. Your now leaky brain barrier can’t stand up to the job of keeping out the chemicals that will ultimately harm your brain cells. Having a damaged blood brain barrier has been associated with brain cancer and other diseases like multiple sclerosis.
What can we do to stop the effects of chronic stress and cortisol?
Surprisingly, it’s actually easier than you might think and effective too.
We’ve heard it before but mediation reduces the stress levels in our brain. A new study from Carnegie Mellon University published in the journal of Biological Psychiatry Journal has shown that meditation reduces inflammation. Dr. David Creswell, a professor of psychology at the university and the study’s lead author says, “Many people are skeptical about whether there are helpful aspects of mindfulness meditation practices.” He continues, “This new work sheds light into what mindfulness training is doing to the brain to produce these inflammatory health benefits.”
Mindfulness meditation trains us to ignore the daily traffic of thoughts running through our minds. It teaches us to be still, to be calm, to sit in the present without the fear of the future or the regret of the past impinging on the peace of the moment. Essentially it does the opposite of stimulating your flight or fight response. It elicits peace and tranquillity, producing if you will a balance to the stressful stimuli, returning homeostasis to the body.
Food is another powerful way to combat the effects of stress. What we’re trying to achieve here is minimizing the effects of free radicals. The body has its own defence system against free radicals, called antioxidants. Antioxidants bind with free radicals to stop them doing damage. Whilst there are several enzyme systems in the body that scavenge for free radicals, your body cannot produce antioxidants by itself. Instead, your body gets them from food. Vitamin E, Vitamin C and Beta-carotene (Vitamin A) are all excellent antioxidants. Start with a diet high in antioxidant rich food, certain fruit like dark coloured grapes, blueberries and raspberries are great. Or nuts and dark green leafy vegetables are good choices. Green tea is a particular favourite.
BDNF is the protein that helps build new brain cells and it keeps your existing brain cells strong. You can rapidly increasing your BDNF by getting daily exercise. You don’t have to be running for gold, walking is just as good. And so are activities like yoga and tai chi.
Stress is a direct response to thoughts we have about the world around us. It is a physical reaction to the issues that confront us. Whilst our brain continues to perceive these situations as threats, stimulating an onslaught of biochemical reactions inside us, we have the ability to halt it. However, to do that requires some effort on our behalf. We need to be conscious about the food we eat, the daily exercise we get and even, the very thoughts we think.