Upon opening your eyes in the morning , do you crave the acidity and kick of a freshly brewed cup of coffee ? Or do you prefer the soul-warming heat and more subtle caffeine hit from a cup of tea ? Surely, experts agree that one must be better for our health than the other, right?

It turns out that as fierce as the battle between coffee and tea lovers may be, theres no straight answer that applies across the board.

It really depends on the person, said Tamar Samuels, a registered dietitian and co-founder of Culina Health , explaining that ones preference has just as much to do with a bodys reaction to each drink as it does with ones taste buds.

Keep in mind that any noticeable health benefits or drawbacks of drinking coffee in particular but also tea are directly connected to caffeine, which happens to be the worlds most widely consumed psychoactive drug . And according to Samuels, the effects of caffeine can be experienced within 45 minutes of consumption and can last anywhere between three to 10 hours, depending on the person.

Heres what caffeine does to your body and mind in the morning

Coffee and tea obviously both contain caffeine, but at different levels.

One 8-ounce cup of black coffee contains about 95 milligrams of caffeine, whereas the same amount of black tea boasts 48 milligrams, Samuels said. A cup of green tea comes with around 29 milligrams. Clearly, in this example, the effects of caffeine will be most readily felt when indulging in a cup of coffee.

Most of the benefits of caffeine truly depend on the drinkers genetic disposition.

We metabolize caffeine in the liver, and some people have genetic mutations that make them fast or slow metabolizers of caffeine, Samuels said.

Caffeine is metabolized by an enzyme in the liver that is encoded for by the CYP1A2 gene. About half of the worlds population possesses a variant of that gene that leads to the slow processing of the stimulant, Samuels said, and its difficult to genetically test for it.

The best way to assess your tolerance is by monitoring your symptoms and working with a nutritionist, she said. As a rule of thumb, if you feel jittery, have difficulty sleeping and detect a rapid heart rate after consuming caffeine, try to stay away from having too much of it.

Our stress levels can also affect the way we deal with caffeine because both caffeine and stress can elevate cortisol levels , which is bad for the body in the long term.

People who are chronically stressed dont do well with caffeine, Samuels said, listing insomnia, digestive issues, anxiety and high blood pressure as possible side effects . However, its important to note that only large amounts of caffeine raise your cortisol levels enough to spark negative side effects, whereas small to moderate amounts of the stimulant can give you a healthy boost.

Speaking of cortisol, the human body already has naturally high levels of the hormone in the morning in the first place.

The problem with having caffeine in the morning is that your cortisol is already high and the caffeine increases that, so it can produce a lot of anxiety and jitteriness in the morning, which can throw the rest of your day off, Samuels said. A good way to counteract that is by drinking your caffeinated beverage with food .

Caffeine also naturally contains methylxanthine, which is used by medical professionals to combat airway diseases. Methylxanthine affects the bodys serotonin neurons, which provoke many of the alerting effects associated with caffeine intake, according to Dr. Kimberly Langdon, a member of the medical advisory board at the health services company Medzino . Methylxanthines have been linked to higher levels of vigilance and arousal , which are functions that are intricately connected to serotonin neurons.

Overall, caffeine affects the central nervous system in multiple ways, Langdon said. On one hand, it increases energy throughout the brain, but it also decreases cerebral blood flow, inducing relatively low blood pressure. On the other hand, it activates noradrenaline neurons as well as the local release of dopamine, also leading to alertness.