Human beings are constantly facing various challenges, and our body has to adapt to this in order to be able to survive. These challenges are also known as ‘stress’. Stress can be chronic or acute, but in the world we live in today, it is generally chronic stress, which means it continues for long periods of time.
Acute stress means our body goes into ‘fight or flight mode’. The hypothalamus in the brain coordinates all the actions necessary for response to the stress that we are faced with. When it does that, it releases CRH (corticotropin-releasing hormone) or cortisol. With chronic stress, cortisol is released continuously, meaning we are always in fight or flight mode.
Why Cortisol Can Be Dangerous
When we are faced with extreme excitement, our body released norepinephrine and epinephrine (adrenaline). These two hormones enable us to make quick decisions. Both are also dissipated very rapidly. But then, there is cortisol. This stays in our system for the rest of the day, and this is also why it can be dangerous. Some even call it ‘public enemy number one’.
If you have too much cortisol in your system, you can experience a number of health problems, including:
• Weight gain
• Hormonal imbalance
• Digestive issues
• Heart disease
When you are constantly faced with stress, you can feel tired, but still wired at the same time. As a result, you will struggle to sleep, have issues with your memory, and more. Perhaps, most worrying is the fact that cortisol can actually kill some of your brain cells, often faster than what the brain can regenerate them.
The adrenal glands, found just above your kidneys, release cortisol, which is a type of steroid. It is necessary for instant fight or flight responses, but should only be released in small amounts. It also affects levels of blood sugar and your immune system, for instance.
What Happens During Stress?
When you are faced with a stressful situation, your body stops working on all important things such as digesting, keeping your immune system in check, or making sure you are fertile. After all, your body thinks that you are facing an emergency situation, so those things are of secondary importance.
Instead, your heart rate starts to increase, your blood pressure goes up and your breathing becomes quicker. This also ensures your muscles are full of blood filled with energy. To make sure you are ready to move, your liver also starts to release lots of sugars. These reactions have been necessary for the human race’s survival, ensuring we were able to take appropriate action when faced with predators.
Stress Kills Brain Cells
There have been a number of animal studies that have shown cortisol kills blood cells. Rats were injected with cortisol, or subjected to daily stresses, and both showed a reduction in the number of brain cells. Most importantly, it affected the hippocampus, which is the part of the brain that is responsible for memory. What researchers found was that the brain quite literally becomes too excited when exposed to cortisol. A cascade of reactions takes place in the various receptors, leading to excess levels of calcium being released, eventually killing the cells.
Our body has an amazing ability to regenerate and create new cells. However, research has now found that cortisol not only kills brain cells, it also slows down the rate of cell regeneration. Interestingly, taking drugs that heighten levels of serotonin, like antidepressants, increases the rate of cell regeneration. This suggests that there may also be a link between depression and stress.
Simply put, too much cortisol can kill you, and it will do so in a variety of ways. These ways include:
• Chronic health conditions
• Heart disease
• High cholesterol
• Alzheimer’s disease
• Reduced sex drive
• Memory problems
Our brain is full of cells and each and every one of them is important to our body and cognition. These are known as ‘gray matter’. The other half of the brain, however, is ‘white matter’, which is where all the different parts of our body can communicate through. The hippocampus, which is part of ‘white matter’ has been shown in numerous studies to shrink significantly when exposed to cortisol. As this part of the brain is responsible for emotions and memory, it can lead to some very significant problems.
Malfunctioning Brain Cells
Cortisol is believed to be the human finger in a long line of dominos. There are lots of pathways found in between the hippocampus and the amygdala and if the brain is constantly in fight or flight mode, this starts to make the cells malfunction. Scientists now believe that cortisol changes some of the stem cells, making them stop messages from going to the prefrontal cortex.
So how can stress kill us? Essentially, this is done by killing certain cells in our brain at a rate that we cannot compensate for. In addition, it can also turn some of our cells against us. We live in a world where we are constantly under stress. We have to meet professional, financial, social, personal and family obligations. We are always worried about where the next paycheck is going to come from, whether we can make ends meet, and whether or not we can get to various places on time. We are simply too busy. Add to that the fact that we are also exposed to very real dangers – like crossing a road when someone, who is most likely also stressed, is speeding – and these further increase our levels of cortisol.
It is vital that people learn how to breathe, take time out, and let their body settle down once again. This is the only way to protect our brain and to make sure it lasts as long as we do ourselves. Premature aging, loss of memory and cognitive function and Alzheimer’s disease are all things that we would like to avoid.
Resources and References:
The Relationship Between Stress and Disease Information on how cortisol and testosterone levels are linked to chronic diseases. (The Cortisol Connection)
New Evidence that Chronic Stress Predisposes the Brain to Mental Illness – Link between chronic stress and mental illness. (Berkeley News)
Chronic Stress Puts Your Health at Risk – Effects of chronic stres on health. (Mayo Clinic)
Cortisol Connection: Tips in Managing Stress and Weight – Clarifies some misconceptions on cortisol and suggests ways to manage stress. (University of New Mexico)
Cortisol and Decision Making – Study showing that stress-induced cortisol helps in decision-making by police officers when under threat. (Columbia University)