Everything You Need To Know About Cortisol

Fear is an uncomfortable feeling. The adrenaline rush you get when you see a car drifting into your lane on the highway or before a roller coaster starts its descent is thrilling to some, but others want to avoid it. Although it seems like it happens at lightning speed, the rush you feel from a fearful event is caused by a cocktail of hormones. Collectively, they're called the adrenal hormones. They're secreted by the adrenal glands, which sit on top of your kidneys (per the Endocrine Society).

Among these hormones is cortisol, which is sometimes referred to as the stress hormone. Other hormones released by the adrenal glands include adrenaline and norepinephrine. They do more than just make you afraid, though. They regulate things like your immune system, blood pressure, and metabolism. Cortisol is also used to regulate systems in your body, and plays an important role in normal body functioning. You might not want to feel fear all the time, but these stress hormones are important and even healthy in the right amounts.

Cortisol and the fight-or-flight reponse

Your body's response to danger is sometimes known as the "fight-or-flight" response. It's also called the acute stress response, explains an article from the American Institute of Stress

The fight-or-flight response is how your body reacts to an immediate threat, like seeing a bear in the woods approaching you. Your adrenal glands produce hormones called catecholamines, including epinephrine and norepinephrine. These hormones get your body ready to either deal with the threat head-on or flee from danger as quickly as possible. They do so by increasing your heart rate, blood pressure, and breathing.

Cortisol isn't considered one of the primary fight-or-flight hormones, but it's released during the fight-or-flight response, according to the Cleveland Clinic. The fight-or-flight response is meant to last only a short period of time, and wears off after the threat is gone. However, cortisol can keep you alert longer than the initial adrenaline rush from the fight-or-flight hormones.

The different types of stress

The initial fight-or-flight response is part of the acute response to stress, explains the Cleveland Clinic. If you're still on high alert and unable to relax, the initial acute stress can turn into chronic stress. This is your body's response to something that's ongoing, such as problems at work or dealing with a chronic illness. Cortisol plays a role in both chronic and acute stress.

Another type of stress is traumatic stress, which is different from acute and chronic stress. If you've experienced something terrifying such as war or a natural disaster, you may feel stress after the event for quite some time. Traumatic stress is a precursor to post-traumatic stress disorder. Cortisol is released during traumatic stress as well. 

Cortisol is known as the "stress hormone" due to the fact that it's present in all types of stress. In contrast, catecholamines are part of the body's acute stress response.

Cortisol's role in chronic stress

Stress that goes on for too long can be damaging to your body and your psyche. According to the University of Utah, some signs of chronic stress are headache, dry mouth, overeating or undereating, and loss of libido. These unpleasant symptoms are indicators of consistent stress in your life. They can also point to high cortisol levels. 

study published in the Journal of the American Physical Therapy Association found that long-term stress can cause cortisol dysfunction. The researchers explain that cortisol normally decreases inflammation in the body. It also helps consolidate memories when you're in fight-or-flight mode. However, if you're under constant stress, you can deplete your cortisol levels or cause cortisol dysfunction, which makes it less effective. When that happens, inflammation in your body increases. In these instances, pain can increase as well. Long story short, chronic stress can have terrible consequences for your body.

The HPA axis controls cortisol

The glands that produce cortisol are called the adrenal glands, and they're located above your kidneys. However, the true controller of cortisol levels in the body is the brain. Using something called the hypothalamic-pituitary-adrenal axis, the brain can send a group of steroid hormones, called glucocorticoids, into the bloodstream. One of these glucocorticoids is cortisol, explains the American Psychological Association

There are three components to the HPA axis. The first, the hypothalamus, is a part of your brain that's also connected to the endocrine system. Your hypothalamus sends a signal to the pituitary gland to produce a hormone which goes down to your adrenal gland. From there, the adrenal gland will make the cortisol you need and send it out through your bloodstream. Interestingly, the HPA axis is sensitive to your circadian rhythm, which means that the time when you sleep and wake up affects cortisol levels. They tend to be higher in the morning and lower at night, according to an article published by StatPearls.

Cortisol's effects on the body

Although it's an important part of the stress response, cortisol isn't limited to stressful events. Your body produces and regulates cortisol levels constantly. One use for cortisol, according to the American Psychological Association, is to tell your liver to send glucose and fatty acids out into the bloodstream. This is one way that the body can call for energy that's stored in the liver to be used by other things like your muscles. 

Cortisol is used to reduce inflammation and boost your immune system. Only when you have impaired communication between the HPA axis and your immune system does inflammation increase and immune activity decrease. Cortisol primes your cardiovascular system for activity by raising your heart rate and breathing rate. It also causes blood vessels in your limbs to dilate, which increases blood flow. (You don't necessarily need to be chased by a bear to need cortisol, though — it can simply give you energy for, say, a workout.)

Early life stress and cortisol

High cortisol levels can be caused by a number of reasons, including traumatic experiences. However, a paper published in Hormones and Behavior found that stress from childhood doesn't cause long-term elevated cortisol levels. The researchers interviewed people who they identified as having stressful experiences in early life. They tested their cortisol levels in a few settings to see their cortisol response to stressful situations, non-stressful situations, a baseline condition, and cortisol levels in the morning.

Even though they noted that there's a large amount of people who have had early life trauma and continue to experience challenges related to it, cortisol doesn't seem to have any relation. In fact, some people appeared to have blunted cortisol responses, meaning they didn't produce as much cortisol as might be expected. The researchers observed, however, that people who had been sexually, emotionally, or physically abused in early life had elevated cortisol in the morning.

Cortisol fights muscle-building

Cortisol can help the body in certain situations, but it's not always your friend. If you want to build muscle, cortisol can be bad news. 

A study published in Frontiers in Endocrinology looked at a few hormones and how they affect muscle growth. They found that cortisol had a "profound opposing influence" on muscle growth. It might seem counterintuitive because cortisol helps mobilize energy in your body to prepare you for a workout, but it can actually hinder the muscle-building process.

The researchers found that cortisol was highest during intense workouts. That means going to the gym and pumping iron until you're exhausted causes the highest levels of cortisol. They note that overtraining your muscles makes things worse, because it blocks your body's ability to blunt cortisol's muscle-degrading abilities. There isn't much you can do to prevent cortisol from interfering with your progress in the gym, but resting and preventing yourself from doing too much in training could help.

Cortisol and stress eating

When dealing with stress, some people eat too much, while others eat too little. 

Cortisol could have an effect on how much people eat, suggests a study published in Translational Psychiatry. The researchers set out to investigate something they describe as "comfort eating," which is when a person eats too much to relieve the stress they're facing. The researchers split the study participants into two groups: obese people, and those with a healthy weight.

Within the two groups, the researchers separated subjects into high cortisol reactors and low cortisol reactors. They used a test called the Trier Social Stress Test to determine which group each subject fit into. They found that among the obese group, high cortisol reactors tended to eat significantly more than low cortisol reactors. However, there wasn't really any significant difference among people with a healthy weight. That means obese people who are more reactive to cortisol are more likely to overeat when they're stressed out. 

What is Cushing's syndrome?

Cushing's syndrome is the term for high cortisol levels in the blood (per St. John's Cancer Institute). Certain types of tumors can cause abnormally high levels of cortisol, including pituitary tumors and adrenal tumors. Excess steroid medication can also cause high levels of cortisol. You might get steroids prescribed to reduce inflammation. Asthma and arthritis are both conditions that can benefit from steroid medication.

Some of the symptoms of Cushing's syndrome include fatigue and weight gain in the midsection, around your stomach and hips. You may also notice that you're bruising easily and that you have swelling in the legs. Additionally, women can have irregular periods if there's too much cortisol in their bloodstream. Some other signs include medical conditions such as high blood pressure, diabetes, and osteoporosis. St. John's Cancer Institute also notes that some people don't have active signs or symptoms of Cushing's, but still test positive for high cortisol on a blood test.

What is a cortisol test?

If you fear that you might have Cushing's syndrome or your doctor feels the need to test your cortisol levels, you'll typically undergo a simple blood test. 

Like most blood tests, a medical practitioner will take the blood from your vein with a needle. However, unlike a routine blood draw, a test for cortisol might be different. That's because your levels of the hormone fluctuate throughout the day, according to MedLine Plus

Cortisol levels are highest in the morning, so you'll typically have one test done then. On the same day, you might be asked to come back around 4 p.m., when your cortisol levels are typically lower. You might be asked to do a urine or saliva collection instead. For a urine test, you'll need to collect a sample each time you urinate over a 24-hour period. Meanwhile, saliva tests are usually done at home, at night. You'll be asked to test by collecting saliva from a swab in your mouth, at least 15 to 30 minutes after eating or drinking.

Adrenal gland disorders and cortisol

A common cause of either high or low cortisol is an adrenal gland disorder, as MedLine Plus explains. Cushing's syndrome is one sign of an adrenal gland disorder, which is caused by abnormally high cortisol levels. Another type of adrenal disorder is Addison's disease, which causes low cortisol levels. While too much of the stress hormone can be harmful for your body, too little definitely isn't good, either.

The most common signs and symptoms of Addison's disease are fatigue, muscle weakness, loss of appetite, weight loss, and abdominal pain, according to the National Institute of Diabetes and Digestive and Kidney Diseases. When you have Addison's disease, the adrenal glands don't produce enough cortisol. This condition may be caused by autoimmune disease or by suddenly stopping steroid medication. Other possible causes of adrenal gland disorder include tumors, both benign and cancerous, that affect the adrenal glands.

Lower cortisol with yoga

High cortisol levels can be a sign of excessive life stress. Since cortisol is regulated by the HPA axis, it's hard to control how much of it your body produces. That said, it's not impossible.

One way to decrease your cortisol is by removing the stress that's causing it in the first place. Yoga is a common stress-relieving practice that could help. Not all styles of yoga are focused on relaxation, but one study published in the Indian Journal of Psychiatry found that a general yoga practice helped reduce cortisol. In the study, the researchers had three groups. The first group took antidepressants, but didn't do yoga. The second group did yoga, but didn't take antidepressants. Meanwhile, the third group both took antidepressants and practiced yoga. Depression raises cortisol levels, explained the researchers, but yoga helped lower it by lowering stress. While they noted the effect yoga had on cortisol levels and depression, the researchers weren't able to fully explain why yoga produces these results.

To lower cortisol, go outside or go to sleep

Some forms of exercise such as yoga can reduce stress and lower cortisol levels. However, that's not the only thing you can do to lower them. Another option is to step outside more often. 

If you're inside all day working on a computer, whether you're at home or an office, some much-needed outdoor time can help. The National Academy of Sports Medicine recommends stepping out for at least 20 minutes per day. They note that people who live in areas with more green space (such as parks) tend to have lower cortisol levels.

Another way you can reduce stress is by sleeping. If you don't sleep enough, this might be the best place to start. Sleep deprivation can cause your HPA axis, which controls cortisol levels, to go out of whack. Not only do you need to sleep enough (which could mean 7 hours of sleep or more per night), but you should also have quality sleep. That means limiting alcohol consumption and screen time before bed.

Diets to lower cortisol

Reducing stress should be your main goal if you want to lower your cortisol numbers, but diet can play a role. 

An article from the National Academy of Sports Medicine says that research on the connection between diet and cortisol has been going on for a while. Foods that contain high amounts of both carbohydrates and fat seem to disrupt cortisol levels. However, those types of food aren't typically found in nature. Additionally, low-carbohydrate diets seem to increase cortisol in women. 

Cutting your calories for too long can also cause your cortisol levels to increase. That means people who are trying to lose weight might want to avoid aggressive dieting, which reduces calories too quickly. Rather, eating a balanced diet seems to be the best for regulating cortisol levels. Eat a moderate amount of carbohydrates and get the required amounts of vitamins and minerals to maintain healthy cortisol levels.