There are times when life becomes full of stress. An overload at work, a family illness, a to-do list that never seems to get done. When there’s so much on the mind that it keeps you awake at night, you begin to develop a sleep deficit, which can lead to a host of health problems.

While fatigue is certainly an issue for people lacking sleep, the larger concern is what happens when the chemistry of the brain does not regenerate. This regeneration can only happen when the brain is given a chance to rest. When you go night after night without adequate sleep, the hormones released as a response to stress; cortisol, epinephrine, and adrenaline—are not properly regulated. Over time, your immune system can be impacted because your natural cycles are so out of balance. You begin to function in a “fight-or-flight” state.

Fight-or-flight is launched by your sympathetic nervous system when your body thinks it’s under attack. If, for instance, your airway relaxes in your sleep to the point that it constricts and you begin to choke, your sympathetic nervous system will kick in and launch a flight-or-flight response. That’s what wakes a person with sleep apnea. The body perceives a collapsed airway as an attack and it wakes the person in an effort to save their life. This can happen hundreds of times a night.

The fight-or-flight response releases cortisol, which is a serious problem if it happens all night long. Your body is designed to release cortisol in a cycle. It releases high levels when you wake after a night of rest. Throughout the day, those levels of cortisol decline until they reach a low point, right about the time you’re ready to go to bed. When your body is constantly under stress, it continues to release cortisol to deal with any real or perceived threats. So if you’re tossing and turning all night, your body is continually releasing cortisol at a time when it should be regenerating. This leaves you with low levels of cortisol in the morning and makes it a chore to get out of bed. If this cycle continues, over time your cortisol levels can basically reverse and end up keeping you awake at night.

Unregulated cortisol is caused by stressed adrenal glands. The adrenal glands are two thumb-sized organs located just above the kidneys that regulate dozens of hormones in your body. When your adrenal glands sense that something is trying to choke you, they send out hormones to combat the situation. If your body is under constant stress, or your airway collapses multiple times a night, your adrenal glands may kick into overdrive, pumping out hormones continually until they simply stop functioning properly. That’s what’s known as adrenal fatigue.

The sympathetic nervous system is not supposed to be working hard 24/7. It’s not supposed to fire off hormones when you are trying to sleep at night. But when the body is starving for oxygen, as it does in a patient with sleep apnea, then the sympathetic nervous system is on most of the time.

In all this upheaval, the brain can become hypoxic (oxygen-deprived). At that point, it cannot rejuvenate, detoxify, or create the energy that it needs to function properly. That’s when you begin to experience brain fog, memory loss, and trouble concentrating or making decisions.

When your body’s nervous systems are in balance, the sympathetic nervous system is offset by the parasympathetic nervous system. The parasympathetic nervous system, also known as the rest-and-digest system, helps you sleep by slowing your heart rate, stimulating digestion, and helping your muscles relax. The two systems working together help keep your body in a homeostatic state. A homeostatic body is able to heal itself more readily without medical intervention.

That’s how stress kills: It keeps your body’s systems from being balanced. Over time, the effects of stress can lead to chronic health issues.

Stay tuned for future blogs with strategies for managing stress and improving sleep.