What does stress do?

Stress affects your digestive tract. “The gastrointestinal tract is filled with nerve endings and immune cells, all of which are affected by stress hormones,” says Dr. Dossett. As a result, stress can cause acid reflux as well as exacerbate symptoms of irritable bowel syndrome and inflammatory bowel disease. Not to mention create butterflies in your stomach.

Stress messes with your immune system. A number of studies shows that stress lowers immunity, which may be why you’re likely to come down with a cold after a crunch time at school or work — right on the first day of your vacation. (5) “Patients with autoimmune disorders often say they get flare-ups during or after stressful events, or tell me that their condition began after a particularly stressful event,” says Dossett.

Stress can muddle your brain. “Brain scans of people with post-traumatic stress disorder show more activity in the amygdala, a brain region associated with fear and emotion,” says Haythe. But even everyday kinds of stress can affect how the brain processes information.

“We see actual structural, functional, and connectivity-related brain changes in people who are under chronic stress,” adds Gupta. All of these can affect cognition and attention, which is why you may find it hard to focus or learn new things when you are stressed. (6)

Stress can make you feel crummy all over. Stress makes us more sensitive to pain, and it can also cause pain due to muscular tension. (7) “People under stress also tend to perceive pain differently,” says Gupta.

They’re also less apt to sleep well, which doesn’t help matters. “Sleep is so important in terms of helping to prevent every disease,” adds Haythe. “It helps reboot the immune system and prevents depression, irritability, and exhaustion.”