Not getting enough sleep could be bad for your heart, according to a small new study.

The study, presented at the Experimental Biology 2013 meeting, shows that sleep deprivation may have negative effects on the functioning of our blood vessels and our breathing control — and getting more sleep could improve these functions.

The study included eight healthy adults ages 20 to 35. For two nights, the study participants slept eight hours a night. Then, for three nights, the study participants only slept four hours a night.

Researchers tested the blood vessel function — also known as vascular function, meaning how well blood vessels cope with greater blood flow — of the study participants, and found that the function decreased a lot after two nights of only getting four hours of sleep. However, after the third night of sleep, researches saw that the vascular function returned to its baseline.

They also subjected study participants to higher carbon dioxide levels, in order to boost breathing rate and depth in the study participants. However, they found that when the study participants were sleep deprived, they had worse breathing control during this test.

Because the findings have yet to be published in a peer-reviewed journal, they should be considered preliminary. However, past research has illustrated heart benefits of getting enough shut-eye. A study published last year in the Journal of Sleep Research shows that getting an extra hour of sleep a night could improve blood pressure levels, when you typically get fewer than seven hours a night.