Headaches can happen for a variety of reasons.
Knowing what triggers your headaches, writing this information down in what's called a headache diary and sharing it with your doctor might help you find out what's causing the pain and take steps to avoid or treat it.
Stress tops the list
According to the <a href="[BASEDOMAIN]/healthinfo/bouncelink.aspx?shortcut=headache" target="_blank">National Headache Foundation</a>, stress is the most commonly recognized headache trigger. Anxiety, shock, depression, excitement and mental fatigue can all bring on a headache for some people. Likewise, the muscle tension associated with a stressful situation can make headaches worse.
Other common headache triggers include:
Diet. Skipping meals can bring on a headache, but for some people, particular foods are to blame.
Problem foods may include those with monosodium glutamate&nbsp;(MSG), such as soy sauce or meat tenderizer; processed meats containing nitrates, such as lunch meats; aged cheeses, such as cheddar, stilton and brie; and even chocolate. Too much caffeine can also be a cause.
Environment. Very hot or cold temperatures, high winds, and changes in humidity or barometric pressure affect some people.
Others are bothered by bright, flickering lights, such as sunlight reflecting off snow, sand or water, or even light from television or movie screens. Bright lights also can bring on a headache.
Pollution and other fumes can also be a cause. Carbon monoxide, perhaps from a faulty furnace; smoking, including secondhand smoke; and strong perfumes are sometimes headache triggers.
Physical exertion. Some headaches are brought on by strenuous activities, such as weightlifting and running, or extensive bending and straining. Even less taxing behaviors, such as coughing and sneezing, can result in a headache for some people.
Exercising when you are out of shape or working out in the heat can spark a headache.
Internal workings. What's going on elsewhere inside your body can also translate into headache pain. For example, headaches may be traced to high blood pressure or low blood sugar.
For women, changes in estrogen levels before, during or just after a menstrual period may set off a headache. Birth control pills and hormone therapies can also play a part.
Get help
While most people get headaches, what triggers each person's pain may be different. Knowing what's causing your own headaches may be the first step in avoiding them.
If you have regular headaches or if your headaches are getting worse, talk to your doctor. 
Reviewed 5/22/2023

Headache triggers vary widely 

Anxiety, bright lights, even a whiff of perfume&mdash;all are known causes of headaches. Keeping track of your headache triggers can help you learn how to ease the pain.