Kicking off the day with coffee is a good thing — and now researchers say four cups daily is ideal for a healthy heart.

Caffeine has already been well-documented to carry a host of health benefits from keeping aging at bay to improving blood circulation. Now, new research explains why four cups of brew is the ideal amount for a healthy heart.

Caffeine And P27

In the newly released paper, published in the journal PLOS Biology, a team of German researchers reveals that caffeine actually promotes the movement of a protein called p27 into the mitochondria. Here, it can help the heart by protecting the muscle from cell death and promoting the migration of endothelial cells, which line the inside of the blood vessels.

The researchers, led by molecular biologists Judith Haendeler and Joachim Altschmied, analyzed caffeinated mice and human tissue for the study. In their results, they found the perfect amount of caffeine to induce the migration of p27: four cups of coffee every day.

"When you drink four to five cups of espresso," Altschmied tells Business Insider. "That seems to improve the function of the powerhouses of our cells, and therefore seems to be protective."

It was also discovered that caffeine can protect against heart damage when it comes to in prediabetic, older, and obese mice, according to Medical News Today. Additionally, previous studies have found that the functions of endothelial cells are enhanced by caffeine as well.

"These results should lead to better strategies for protecting heart muscle from damage, including consideration of coffee consumption or caffeine as an additional dietary factor in the elderly population," Haendeler explains in a statement to Science Daily. "Furthermore, enhancing mitochondrial p27 could serve as a potential therapeutic strategy not only in cardiovascular diseases but also in improving healthspan."

But Don't Overdose On Caffeine

Despite the benefits of your daily brew, it's still important to control the dose of caffeine you drink, the scientists are quick to add. It's not only important to remember that coffee does not replace exercise and proper diet, but overdoing caffeine consumption also comes with potentially harmful effects.

While Business Insider notes that cardiologists say up to six cups a day is okay, too much coffee can cause a spike in the heart rate and lead to other health problems.

Altschmied adds that caffeine is known to make blood vessels grow and funnel more oxygen to tumors, so cancer patients may not be well-equipped for the four-cups-a-day recommendation.

"But if you're otherwise healthy, it will not harm you, and it might help your heart and circulatory system stay better functional for a longer time," he says.

You may want to consider Decaf Espresso to begin with. Read Decaf Espresso - what it is and why you should try it for more information.