Anytime your body is not “happy” about something, it gets stressed. If you are in pain, if you injure yourself or break a bone, your body gets stressed. If you get an infection in your throat, ear, bladder, skin, lungs, or anywhere in your body, it causes stress. If you are too cold or too hot or wet or starving, your body gets stressed. And if you are angry or unhappy or worried or scared, that can be stressful to your body, too. So everything from physical injury to psychological problems can cause stress.
Funnily enough, your body responds to all of these different kinds of stress in a very similar way. It releases large amounts of the hormones adrenaline (also called epinephrine), noradrenaline (or norepinephrine), glucagon, cortisol, and growth hormone. These are sometimes called the “stress hormones.” They act in different ways to raise the glucose level in your blood by encouraging glucose to be released from your liver. They make it harder for insulin to work properly, and so they make your body more resistant to the effects of insulin.