You’ve probably heard (or even experienced) that consuming caffeinated beverages too late in the day can affect your ability to fall asleep, but have you every wondered why caffeine has the response it does on your body? The effects of caffeine in drinks, foods, and medications vary from person to person and it can impact your physiological health with unexpected side effects.

According to, caffeine is both a drug and food additive. It changes the way your brain and body work and as well as how you behave and feel. Caffeine stimulates your central nervous system, which includes your brain, spinal cord, and the other nerves in your body. While caffeine’s effects are that it makes you feel more awake and alert for a while, it can also cause some issues. If you suspect you’re caffeine sensitive, consider cutting back your daily intake, and ask your physician or pharmacist if any of your prescriptions or OTC medications (like pain medications) contain caffeine. Most doctors suggest keeping your caffeine intake from 100 to 200 mg (one to two 5-ounce cups of coffee) daily. For reference, a “short” Pike Place Roast coffee at Starbucks is 8 fl. oz. and about 180mg caffeine, and a “tall” is 12 fl. oz. and 260 mg caffeine.

Here are a few ways caffeine can impact your health:

It can affect your heart.

People with heart problems are often advised to avoid caffeine because this stimulant makes the heart beat faster and it can make their hearts in particular work too hard. It also can create an uneven heart rhythm and raise your blood pressure.

It can affect your mood. 

While you may rely on a morning java habit to give you a mood boost that’ll get you through a busy morning, stressful commute, or annoying coworkers, caffeine can evoke different feelings in others. It might make you feel nervous or on-edge. People who have anxiety issues or previously experienced panic attacks may find that caffeine makes them feel worse.

It can make you feel jittery. 

If you’ve ever experienced shaky hands or jittery feet after consuming a large caffeinated drink, you know how hard it is to sit still when this stimulant is surging through your body. Too much caffeine can even cause tremors in your body.

It may cause heartburn. 

Heartburn is the most frequently reported symptom after coffee drinking, and research says that coffee could promote gastro esophageal reflux. Coffee stimulates gastrin release and gastric acid secretion,

It can make your head hurt. 

Caffeine can be a headache trigger or headache inhibitor. You may have experienced withdrawal symptoms—like headaches, irritability, nausea, or trouble concentrating—if you’ve skipped your daily caffeine fix. This could be a sign that you have a physical dependence on caffeine. On the flip side, having too much caffeine can also cause headaches or even migraines. Although most headache sufferers can consume up to 200 mg. per day, the National Headache Foundation advises patients with frequent headaches to avoid daily use.

It may act as a laxative. 

Caffeine can speed up your overall metabolism, which includes the your digestion and elimination processes. It can also cause your gastrointestinal muscles to contract, having a laxative effect. Some people my use coffee for this effective to help them have bowel movements, but keep in mind that caffeine acts as a diuretic and can also cause sufficient fluid loss through diarrhea and dehydration.

It can derail your sleep schedule.

You might think an afternoon “cuppa joe” is mandatory in order to get through the rest of your workday without crashing, but that caffeine can stay in your system for at least six hours after you’ve finished it, according to The National Sleep Foundation (NSF). After caffeine enters the bloodstream through the stomach and small intestine, it can have a stimulating effect of alertness in as little as 15 minutes after it’s consumed. It makes you feel more alert by “blocking sleep-inducing chemicals in the brain and increasing adrenaline production,” according to the NSF website. So even though your body is biologically wired to start winding down and help you get ready for sleep as the day wears on, the caffeine is stopping those chemicals, which can by why you still feel wired or are mentally awake even though you’re physically sleepy at bedtime. Most sleep doctors suggest curtailing the caffeine after 2 p.m. so you can get a good night’s sleep.

Bottom line: If you think caffeine in the form of coffee, tea, soda or energy beverages is causing side effects that negatively impact your health, start weaning off them to feel better.