Mmmm, coffee. If you're anything like me, you can't live without a morning cup (or four). But with all the fear mongering about how caffeine might give you heart disease or cancer, you may be feeling a little freaked out about the habit.

I was mainly terrified at the prospect of having to quit coffee, so I did some research and talked to Dr. Matthew Chow, a neurologist and assistant clinical professor at UC Davis, to get the lowdown on caffeine intake. He told me everything you need to know, including who should stay away from the stuff, what health benefits it could provide and how to know when you need to quit.

Who shouldn't drink caffeine?

Chow explains that children should refrain from ingesting any caffeine, as well as people with heart disorders (specifically arrhythmias) or peptic ulcer disease.

The main reason that kids should stay away from caffeine is because they tend to drink it in the form of sodas and energy drinks. These beverages are marketed toward children, but contain high levels of sugar and can contribute to childhood obesity and health disorders. The caffeine in those beverages could potentially be harmful when concentrated in childrens' smaller bodies as well, so Chow recommends that kids don't consume any at all.

Chow also notes that anyone who is pregnant should stay away from caffeine, though the evidence behind this rule of thumb is inconclusive. There are differing opinions about this guideline in the medical community -- Dr. Deep Bhatt of Weill Cornell Medicine tells CNET in an email statement that pregnant people should keep their caffeine intake below 300 milligrams per day. Anyone who is concerned about their caffeine intake while pregnant should talk to their doctor.

How much caffeine should I drink?

For anyone who's cleared to drink caffeine, the upper limit is about 400 milligrams per day. That equals four cups of coffee, 8 cups of green tea or 10 cans of soda. However, this guideline is highly personal -- if you feel jittery or uncomfortable when drinking caffeine, consider limiting yourself further.

Will caffeine give me heart disease?

One comprehensive study debunked the myth that moderate caffeine intake in healthy adults leads to an increased risk of atrial fibrillation or arrhythmia. It also has not been demonstrated to raise the chance of coronary artery disease, myocardial infarction or stroke.  

While caffeine causes a short-term increase in blood pressure (lasting for around three hours), it hasn't been shown to raise your blood pressure on a long-term basis. Still, anyone with chronic high blood pressure should talk to their doctor about consuming caffeine, or consider cutting back.

Is it bad if I'm addicted to caffeine?

It depends. If you find yourself physically dependent on caffeine, Chow says that it's a good idea to ask yourself why. Do you chug coffee throughout the day because you don't sleep well at night? If so, it's time to focus on getting enough high-quality rest during the nighttime instead of ordering more double shot espressos. 

Again, if you're dependent on caffeine and also have a heart disorder, high blood pressure or any other chronic health conditions, you should highly consider weaning yourself off. Chow explained that a large part of caffeine addiction is psychological -- sometimes all we really want is a warm beverage in the morning. Substituting a latte for a hot cup of herbal tea may give you that same good feeling.

Other than that, if you keep your caffeine intake to a safe level, there's not necessarily a compelling reason to force yourself to quit. Those two cups of black coffee in the morning most likely aren't doing you any harm.

Are there any health benefits to caffeine?

You're probably fairly familiar with the short-term cognitive benefits of caffeine: increased concentration, memory, alertness and attention. These advantages come from the fact that caffeine stimulates the sympathetic nervous system, meaning it activates your flight or fight response. Chow explains that people usually experience the benefits of caffeine most when they've gotten insufficient sleep.

One study suggested that drinking moderate amounts of coffee reduces the risk of several different types of cancer. However, the mechanism behind this correlation is unclear -- the lowered risk of cancer could come from the antioxidants naturally present in coffee, and not the caffeine. While the caffeine itself may be inconsequential, drinks like green and black tea contain plant chemicals that are suggested to reduce inflammation and the risk of cardiovascular disease. 

The bottom line? As long as your doctor clears you to drink moderate amounts of caffeine, it's a very safe substance that might even have powerful health benefits. Just make sure you're in it for the right reasons.

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.