Stress isn't just something that happens in your head - the effects reach almost every part of your body.

In simple terms, stress is the way your body responds to potential dangers. When your brain notices a threat, it directs certain glands to release a flood of hormones - namely adrenaline and cortisol - that increase alertness, heart rate, blood flow to your muscles, and more.

Stress is not inherently evil or bad for you. It's a biological response designed to help us successfully escape threats. In an ideal world, your body responds to stress then returns to its normal state.

But in a less-than-ideal world (say, a world where work emails keep your phone buzzing til 10 p.m.), stress can become chronic rather than temporary. That's when it can start to negatively impact your health.

So what does happen to your body if you're stressed all the time? Insider spoke with Cindy Geyer, MD, and Joel Kahn, MD - both members of the True Health Initiative - to find out.


Chronic stress ruins your sleep.

According to the American Pyschological Association's 2019 Stress in America survey, most Americans say they experience higher than normal stress levels. That can take a toll on sleep quality.

"You can get into a vicious cycle," Geyer, the medical director at Canyon Ranch in Lenox, Massachusetts, told Insider. "If you're stressed and you can't turn off your worries and your anxieties, you can't get to sleep, or you wake up more, or you look at the clock and you can't get back to sleep."

One 2019 study found that just one sleepless night could lead to a 30% increase in stress levels, while a 2015 study that tracked middle-aged women over a nine-year period found that those who reported the highest levels of stress had lower quality sleep and were more likely to report having insomnia. Medical research shows poor sleep has been associated with everything from anxiety to depression.

Chronic sleep deprivation can increase the risk of heart problems, obesity, and diabetes - and it can limit your body's ability to fight off infections, according to the National Institutes of Health.


When you're stressed, you make worse food choices.

"People that are stressed may use food as a comfort," Kahn, clinical professor of medicine at Wayne State University School of Medicine, told Insider. "You don't usually munch on broccoli when you're stressed. You're usually grabbing for a doughnut and chips."

While not everyone stress-eats, stress leads to a fight-or-flight response in most people, which can release hormones like adrenaline and cortisol, which increases appetite. Persisting stress can lead to elevated cortisol levels, according to Harvard Health Publishing. When a stressful event events, cortisol levels should decrease. But for people stuck in a cycle of stress, cortisol levels may remain elevated and people may still feel an urge to eat sugary, fatty snacks.

One landmark 2007 study found that people with higher cortisol levels were more likely to snack in response to stress.

Women are more likely to stress-eat than men. One 2014 study found that stress-eating was more common in girls than boys. The American Psychological Association found that women are more likely than men to report stress-eating, with 31% of women reporting eating during tumultuous times versus 21% of men.

Geyer also noted that stress can also mess with leptin and ghrelin - two hormones that regulate our desire for food - spurring us to eat more.


If you're stressed, you might not want to work out.

For some people, exercise can be a form of stress relief, boosting endorphins and improving mood. Exercising can reduce levels of stress hormones like adrenaline and cortisol, and stimulate the production of your brain's natural painkillers, endorphins.

"Human and animal research indicates that being physically active improves the way the body handles stress because of changes in the hormone responses," Erica Jackson, associate professor of movement science at Delaware State University, wrote in ACSM Health and Fitness Journal. "That exercise affects neurotransmitters in the brain such as dopamine and serotonin that affect mood and behaviours."

A handfulofstudies have associated lowered anxiety levels with short-term aerobic exercise. One 2014 study found that people who played sports in middle and high school were less likely to get depressed or stressed as young adults. Another 2018 study found that people who exercised were 17% less likely to have depression.

But often people that are stressed don't make time to exercise. "People that are stressed - if it's because of their schedule and time - they're going to skip the gym and boot the exercise from their life," Kahn said.

Still, there's a heap of evidence showing a workout might make you feel better.


It can also wreak havoc on your hormones.

During periods of chronic stress, Geyer explained, the hormones that regulate menstruation can be suppressed, causing women's periods to become irregular or stop altogether. One 1999 study even found that 50% of women in high-stress jobs were likely to have short menstrual cycles of under 24 days.

"There's an evolutionary mechanism behind this, because if you're stressed, it's not the optimal time to have a baby and be fertile," she said.

But women aren't the only ones affected, and men can see their sperm counts can go down in times of chronic stress.

For both women and men, stress can trigger a hormone imbalance. "When patients come to me for hormonal imbalance, the root cause is usually too much cortisol or stress hormone," Dr. Jane Oh, an OB-GYN in Illinois, told Healthline. "Then downstream - every other hormone in our bodies is affected, including sex hormones and thyroid."


Stress can exacerbate skin problems — including acne.

It's no surprise that stress can negatively affect the largest organ in your body; your skin. Researchers have identified a number of conditions aren't necessarily causedby stress but can be made worse by it. That list includes acne, psoriasis, rosacea, alopecia, and eczema, too.

"It is very common for people to experience breakouts when stressed," dermatologist Marisa Garshick previously told Insider. "Your body releases stress hormones including cortisol, which may increase the skin's oil production, making you prone to breakouts."

Increasec cortisol can also break down collagen and decrease synthesis of hyaluronic acid, Garshick said, adding that this loss of collagen and hyaluronic acid "can lead to fine lines and wrinkles over time," and even premature aging.

When you're stressed, research finds it can take your skin longer than usual to heal up wounds.


And it's not great for your heart.

During acute episodes of stress, the body is flooded with adrenaline, which increases heart rate and blood pressure. In cases of extreme stress, you can even experience a condition known as "broken heart syndrome" - it feels exactly like a heart attack.

Kahn told Insider that long-term stress can negatively affect your heart health, too, though the reason why isn't totally clear. We don't know whether stress itself raises the risk for problems like heart disease, or whether stress simply leads to non-heart-healthy habits, like smoking.

Experts still can't say for sure if stress independently affects your heart health, or if the ways you cope with stress, whether that's through a poor diet or a cigarette, can cause a heart condition. But both the American Heart Association and the US National Library of Medicine both agree that managing stress is a good thing for your heart.


Stress could make you more likely to get sick.

Some experts say it's still not clear whether stress makes you more likely to catch colds or other infections, but there are several studies backing up the idea. One 2015 study shows 60-80% of doctor's appointments are stress-related. Another 2015 study showed that stress could cause people to catch fever. Stress has also been linked to allergy and asthma onset.

"Stress can make the allergic response worse," says Dr. Ahmad Sedaghat said in a Harvard Health letter. "We don't know why exactly, but we think stress hormones can ramp up the already exaggerated immune system response to allergens."

In a 2012 study, for example, 276 healthy adults were quizzed about the level of stress in their lives. Then they were given nose drops containing live rhinovirus - a frequent cause of the common cold. Those who reported being stressed were twice as likely to get sick.


Stress could trigger depression.

When it comes to depression and stress, "it's sometimes tough to tease out which is the chicken and which is the egg," said Geyer. "But there's clearly a strong link."

Some research says that stress can suppress the growth of new neurons in the hippocampus. That's a part of the brain that's shown to be smaller in some depressed people. Geyer also noted that in some people, chronic inflammation appears to play a role in the onset of depression. And chronic inflammation, can be caused by chronic stress.

"Stress, or being stressed out, leads to behaviours and patterns that in turn can lead to a chronic stress burden and increase the risk of major depression," Bruce McEwen author of The End of Stress as We Know It, told WebMD.

The bottom line is that depression can be caused by a combination of factors. Still, the National Institute of Mental Health does list stress as a risk factor for the disease.


And it can make your digestive system go haywire.

If you've ever felt like throwing up before giving a speech or a presentation, then you already know that stress has a direct effect on your gut. In fact, it's known to cause symptoms like heartburn, indigestion, nausea, vomiting, diarrhea, and constipation. That's because your brain and your gut are closely connected and controlled by many of the same hormones, according the University of Maryland Medical Center.

There are millions of neurons in the gut that communicate with the brain, and stress can affect this connection, triggering pain and gut discomfort. People who stress-eat may feel some heartburn or acid reflux after eating.

"Although stress may not cause stomach ulcers or inflammatory bowel disease, it can make these and other diseases of digestion worse," Kenneth Koch, professor of medicine in gastroenterology, told Everyday Health.


Diet, sleep, and exercise are the doctor-recommended ways to relieve stress.

Kahn told Insider that his top three strategies for relieving stress are eating a healthy diet, exercising, and getting enough sleep.

"Number one is to eat for your brain, which is also to eat for your whole body," Kahn said. He recommends booting processed foods and eating a diet mostly (but not exclusively) plant-based foods. Some studies show that people who eat more fruits and veggies report lower stress levels.

"Number two is fitness," he said. "And fitness can be simply walking from the car to work, using the stairs, or walking during a lunch break." Exercise doesn't have to be ridiculously intense for it to be beneficial.

"Number three, I'd put good sleep. Seven and a half hours is the goal," he added.


And finally: Take time to listen to your body and talk to your friends.

It's important to note that symptoms of chronic stress are different for everyone. "The things that cause me stress may be very different than the things that cause you stress," said Geyer. "And how much of a load is too much for any given person may be different."

But no matter how stress affects you, talking to your friends and listening to your body is crucial, said Geyer.

"We often get little cues that we're stressed, like scrunched up shoulders or queasy stomach or irritability or exhaustion, but we either ignore them or medicate them or plow through," Geyer said. "If you notice your shoulders are scrunched up, [ask yourself] 'Okay, what's driving that?'"

Caroline Praderio contributed to an earlier version of this story.

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