Your traffic light just turned green, and you’re about to pull out into an intersection when you notice another car is barreling through and will hit you. Quick, hit the brakes! The car passes in front of you; the crash is averted. Your heart is racing. You’re holding your breath. Exhale. Your hands are gripping the steering wheel tightly, and your entire body has tensed in anticipation of the collision. Relax, you’re safe.

In that split-second, near-miss accident, several systems in your body kicked into gear. One of those is a part of your brain called the hypothalamic-pituitary-adrenal (HPA) system, which released  a cascade of chemicals—such as adrenaline, steroid hormones, and cortisol—that kicked up your heart rate, helped your brain with that split-second decision, and increased glucose in the bloodstream to give you a burst of energy to react. You didn’t even have to tell it what to do. This is your body’s natural reaction to stress.

But what is not natural is continuously facing stressful situations and challenges day after day. This is known as chronic stress and can be detrimental to your health. Forty-three percent of adults say they suffer adverse health effects from stress, and three-quarters of all doctor’s visits are the result of stress-related ailments and complaints. Stress is also linked to several serious diseases and unhealthy situations, such as heart disease, cancer, lung disease, accidents, cirrhosis of the liver, and suicide.

It’s important to understand how stress can impact your day-to-day life as well as your long-term health. Here are some ways that chronic stress may affect your physical and mental health.

Brain

Stress can impede your thought processes and hamper your thinking. You may find making simple decisions like what to have for dinner or remembering directions to a restaurant are more difficult than in a nonstressed state.

Emotions

People dealing with chronic stress may be easily frustrated and quick to lose their temper. They may cry more often and spend considerably more time worrying about things than they would without being stressed.

Teeth and Gums

Strange as it may seem, stress can take a toll on your oral health. Stress may cause you to clench or grind your teeth. It’s often done unconsciously or during your sleep, but if it’s not treated, it may lead to problems with your temporomandibular joints. Stress may also lead to gum disease, perhaps because of teeth grinding, less attention to oral hygiene, salivary changes, and impaired immunity.

Heart

In terms of its effect on the body, stress is dangerous to your heart. Stress hormones speed up your heart rate, constrict blood vessels, and make the heart and blood vessels more likely to overreact in the event of a future stressful event. Stress is also linked to high blood pressure, blood clots, and in some cases, even stroke.

Lungs

People with asthma and chronic obstructive pulmonary disease (COPD) often have worsening symptoms during times of chronic stress.

Stomach

Stress may make your stomach uneasy, and you may have increased incidence of nausea, vomiting, and diarrhea. In people with gastrointestinal disorders and diseases like gastroesophageal reflux disease (GERD), irritable bowel syndrome (IBS), ulcerative colitis, and peptic ulcer disease, symptoms may be worsened by stress.

Skin

Stress may make skin problems such as psoriasis, eczema, acne, and rosacea worse. It is also known to bring on cold sores and fever blisters.

Hair

Your hair may fall victim to your stress. When a person is under a great deal of stress, his or her hair may enter the falling-out stage of the hair life cycle. It can occur up to three months after the stressful event, but hair usually grows back within a year.

Muscles

Stress-related tension in your back, neck, and shoulders can lead to muscle pain throughout your body.

Immune System

If it seems you always get sick when you can least afford it, it may be because your stress is suppressing your immune system, making you more susceptible to infection. Stress can worsen symptoms of chronic illness such as rheumatoid arthritis and diabetes.