Dark chocolate is known to have the ability to lower blood pressure, but new research suggests it can also improve attention span.

The recent study was the first to look at the direct influence of chocolate on attention characteristics of the brain using electroencephalography, Northern Arizona University reported.

"Chocolate is indeed a stimulant and it activates the brain in a really special way," said Larry Stevens, a professor of psychological sciences at NAU. "It can increase brain characteristics of attention, and it also significantly affects blood pressure levels."

To make their findings, the researchers looked at 122 participants between the ages of 18 and 25. They examined EEG levels and blood pressure associated with consuming a 60 percent cacao confection. They found participants who consumed the chocolate had a more active and alert brain, and also showed short-term blood pressure spikes.

"A lot of us in the afternoon get a little fuzzy and can't pay attention, particularly students, so we could have a higher cacao content chocolate bar and it would increase attention," Stevens said. 

The researchers also tested chocolate enhanced with L-theanine, an amino acid found in green tea that acts as a relaxant. 

"L-theanine is a really fascinating product that lowers blood pressure and produces what we call alpha waves in the brain that are very calm and peaceful," Stevens said. "We thought that if chocolate acutely elevates blood pressure, and L-theanine lowers blood pressure, then maybe the L-theanine would counteract the short-term hypertensive effects of chocolate."

The researchers observed an immediate drop in blood pressure associated with the high-cacao content and L-theanine treat. The researchers believe this means people suffering from hypertension could eat a bar of this type of chocolate and potentially drop their blood pressure to normal levels. The team hopes this study will encourage manufacturers to look into the benefits of producing high-cacao content and L-theanine.

The findings were reported in a recent edition of the journal NeuroRegulation.