What stress does to the body

Stress is your body's reaction to a challenge or a demand. It is not only a feeling in your head. Your heart, lungs, muscles, gut and immune system all take part.^3,2

A short burst of stress can help you act fast or meet a deadline. Trouble starts when stress goes on for weeks or months and your body never gets a chance to settle down.^3,1 This page explains what happens inside you, what long-term stress can do, and why rest and recovery time matter so much.

The stress response: your body's alarm system

When you face something that feels threatening or out of your control, your brain sounds an alarm. Two systems switch on at once.²

The fast system. Nerves send signals that release adrenaline (a hormone that acts within seconds). Your heart beats faster and harder. You breathe more quickly. Blood moves toward your large muscles, and your liver releases sugar for quick energy.² This is often called "fight or flight."

The slower system. A part of the brain called the hypothalamus signals the pituitary gland. The pituitary then signals the adrenal glands, which sit on top of your kidneys. They release cortisol, a hormone that keeps fuel flowing to your body for a longer time.² Doctors call this chain the HPA axis.

The brakes. A second part of your nervous system, sometimes called "rest and digest," helps your body calm down once the danger is over. Your heart slows, breathing eases and digestion starts again.²

This system is built to work in short bursts. After a scare, most bodies return to their normal state fairly soon.²

What cortisol does

Cortisol is not a bad hormone. You need it every day. It helps you wake up, gives you energy and helps control swelling and the immune system.²

Cortisol has a daily rhythm. It is usually highest soon after you wake up and slowly falls during the day.² Long-term stress can throw off how cortisol and the immune system talk to each other. This has been linked to tiredness, problems with blood sugar and weight, depression and immune problems.²

Short-term stress vs. long-term stress

How long-term stress affects each part of the body

Heart and blood vessels

During stress, your heart rate and blood pressure go up. With chronic stress, they can stay higher for long periods. Over time, this is linked to a higher risk of high blood pressure, heart attack and stroke.²

Long-term stress also causes low-level inflammation (the body's swelling and repair response, turned on when it is not needed). Inflammation in the arteries may make fatty plaque more likely to break open. That can cause a heart attack or stroke.⁶ One 2017 study found that people with more activity in the brain's stress center had more inflammation in their arteries.⁶

The American Heart Association says poor mental health, such as depression, is tied to more heart attacks and strokes. Good mental health, such as optimism, is tied to lower risk.⁶ See depression with heart disease and stroke.

Broken heart syndrome. Rarely, a sudden shock, such as the death of a loved one, can cause a condition called takotsubo or stress cardiomyopathy. The heart's main pumping chamber suddenly weakens. It feels like a heart attack, with chest pain and shortness of breath.⁷ In a study of more than 135,000 U.S. hospital cases from 2006 to 2017, about 9 in 10 people with it were women. Women aged 50 to 74 had the highest rates.⁷ Many people who survive the first days recover within days or weeks.⁷ It needs emergency care, just like a heart attack.

Muscles, aches and pains

Under stress, your muscles tighten to guard against injury. When stress passes, they relax. When stress never lets up, muscles stay tight.² This is linked to tension headaches, migraines, and pain in the neck, shoulders and lower back.² Many people notice a stiff jaw or neck.³

Breathing

Stress can make you breathe fast and feel short of breath. It can make asthma and COPD (a long-term lung disease) worse. Fast, shallow breathing can also bring on a panic attack in some people.²

Stomach and gut

Your brain and gut are in constant contact. Stress can make stomach pain and bloating feel stronger.² It can cause or worsen:²

• Heartburn and acid reflux
• Nausea and changes in appetite
• Diarrhea or constipation
• Flares of irritable bowel syndrome (IBS) and inflammatory bowel disease

Stress does not cause stomach ulcers. Most ulcers come from an infection. But stress can make them feel worse.²

Sleep

Stress and sleep affect each other. A stressful event is one of the most common triggers of insomnia (trouble falling or staying asleep).⁹ Some people's sleep is more easily upset by stress than others'. This trait partly runs in families, and it is more common in women.⁹

A loop can form. Lying awake gives the mind more time to worry, and worry keeps you awake.⁹ Poor sleep then makes the next day's stress harder to handle. Most adults need 7 or more hours of sleep a night.⁵

The best-tested treatment for long-lasting insomnia is cognitive behavioral therapy for insomnia (CBT-I), not sleeping pills.¹⁰ Learn more about insomnia, sleep and mood and healthy sleep habits.

Immune system

Here stress works two ways. Short bursts of stress can briefly strengthen the immune system. This may help with healing a wound or responding to a vaccine.⁴

Long-term stress tends to do the opposite. It can lower the number and strength of protective immune cells and keep low-level inflammation going.⁴ In plain terms, your body may have a harder time fighting off infections.² Some research suggests chronic stress may make vaccines such as flu shots work less well.¹¹ This is one more reason to stay up to date on your shots.⁵

Blood sugar and weight

Stress hormones raise blood sugar to give you quick energy.² When stress is constant, this is linked to a higher risk of diabetes and weight gain.³ Stress can also change eating habits. Some people eat more, and others lose their appetite.³

Skin, sex and reproduction

Long-term stress is linked to skin flares such as acne and eczema.³ It can lower sex drive in both men and women. In women, it can change periods and worsen hot flashes.²

Mood, memory and thinking

Stress can make it hard to focus, make decisions or remember things.^3,5 Over time, ongoing stress raises the risk of depression and anxiety disorders.^1,3 Some people start using alcohol or other drugs to cope, which adds new problems.⁵

Why recovery time matters

Stress itself is not the main problem. The problem is stress with no break. The body is built to switch on the alarm, then switch it off and repair.² When the "off" phase keeps getting skipped, wear and tear builds up across body systems.²

Recovery is something you can practice. The opposite of the stress response is called the relaxation response. Breathing slows, blood pressure drops and the heart rate falls.¹⁰

A few small habits also help: take breaks from the news, write down what you are grateful for, limit alcohol and caffeine, and do something you enjoy each day.^5,1 For more ideas, see coping skills that work or make your own calm plan.

Relaxation methods are safe for most people. A few people feel more anxious at first. If you have a history of trauma, seizures or a serious mental illness, ask your doctor which methods fit you.¹⁰

Stress in later life

Later life brings its own stresses. Common ones include long-term illness, caregiving, grief, loneliness, money worries on a fixed income, and big changes like retirement.¹¹

A few things are worth knowing as you get older:

• Stress can worsen health problems you already have, such as high blood pressure, heart disease, diabetes or lung disease.^3,5
• Women after menopause lose some of the heart protection that estrogen gives, so stress may weigh more on their hearts.² Broken heart syndrome is most common in women over 50.⁷
• Heart attacks can be quiet. Silent heart attacks, with mild or no symptoms, are more common in older adults and people with diabetes.⁸ Do not assume chest discomfort or sudden tiredness is "just nerves."
• Caregivers carry heavy, long-term stress. If you care for someone, your own rest is part of the care plan. See caregiver burnout.

See also stress and burnout and loneliness and health.

When to get help

Talk with your doctor or a mental health professional if:^3,1

• Stress feels too much to handle, or it is hurting your health
• You cannot work, or you struggle to manage at home
• You have new or unusual body symptoms
• You have fears you cannot control, or memories of a frightening event that keep coming back
• You avoid things you used to do, or your symptoms never seem to go away

Your doctor can also check whether another health problem is behind your symptoms. Talk therapy and, for some people, medicine can help.¹ If you take medicines, talk with your doctor or pharmacist before changing anything.

Education only. This page is general information written from the sources listed. It is not medical, legal or financial advice and does not replace a doctor, therapist or lawyer who knows your situation. How we write and check pages.