The stress response

Your muscles tense, your heart races, and your breath comes faster — we all know what stress feels like. The “fight or flight” response is behind it: Your hormones get your body ready to either take on a threat or run from it. If this happens too often — say, every day during your commute — it’s called “chronic stress,” and it can take a toll on different parts of your body and your overall health.

How It Happens

Hormones are chemicals that tell certain parts of your body to spring into action. Your adrenal glands make the ones that help your body prepare to fight or run from danger (adrenaline, noradrenaline, cortisol). When those stay at a high level for a long time, they can weaken your bones and your immune system, mess with your sleep, and make you lose muscle.

Stomach Pain

”Butterflies” are one thing, but if you’re really stressed, you may have nausea and your tummy might hurt. This is natural, because your body may slow or stop digestion during the fight-or-flight response to help you focus.

Bathroom Trouble

If stress closes down your digestive system too often, it can cause diarrhea or constipation and affect your body’s ability to take in nutrients. There also seems to be a link between stress and irritable bowel syndrome, which can cause belly pain and cramping, as well as constipation and diarrhea.

Heartburn and Acid Reflux

People who are under a lot of stress might eat more, or eat more unhealthy food. They also may drink more alcohol or smoke more often. All this can lead to heartburn and acid reflux (when stomach acid comes up into your food pipe). If it’s not treated, it can cause ulcers (open sores) and scar tissue.

Headaches

When you’re stressed, the muscles in your head, neck, and shoulders tighten up. This can lead to tension headaches and migraines. Relaxation techniques may help lower your stress as well as the number of these headaches.

Menstruation

Stress can make a woman’s cycle irregular and cause missed or painful periods. It also may make premenstrual syndrome (PMS) worse — the mood swings and cramping some women get before their periods.

Sexual Desire

Stress can make men and women less interested in sex, but chronic stress can cause real trouble for men in the bedroom. It can lead to erectile dysfunction and affect sperm — how many a man makes and how well they’re made.

Breathing Issues

When you’re stressed, you may breathe harder and faster, which can be a problem if you have a condition like asthma or a lung disease, like emphysema, which makes it difficult to get enough oxygen into your lungs.

Heart Problems

The hormones that get into your system when you’re stressed can be bad for your heart if they stay at high levels. They can raise your blood pressure, which can lead to a heart attack or stroke. They also may cause inflammation of the blood vessels that supply blood to your heart muscle, and that also can lead to a heart attack.

Diabetes

When you’re stressed, your liver releases glucose — a kind of sugar — into your blood to fuel your fight-or-flight response. This can lead to diabetes if you’re obese or at risk for it in other ways. But managing your stress can help control your blood sugar.

Things You Can Do

Just 30 minutes a day of moderate exercise, such as a brisk walk or a swim, can help boost your mood and limit the effects of stress on your body. And if you do it outdoors in the sunshine, you may feel even better

Positive Attitude

Stress can be a good thing in some situations — for example, it can help you meet a tight deadline or focus better on a test or presentation. If you look at it in that light — as friend, not foe — your body may deal with it in a healthier way. You also may lower your stress level if you think of others more often. In one study, people who did nice things for friends and family during stressful times had fewer health issues than those who didn’t.