A Greek study involving 386 middle aged patients (average age 61) with arterial hypertension has found that those who had a midday nap had lower systolic BP than those who didn't. Their average systolic BP readings were 4% lower when they were awake (5 mmHg) and 6% lower while they slept at night (7 mmHg) than non-midday sleepers .

Moreover, midday sleepers had pulse wave velocity levels that were 11% lower and left atrium diameter was 5% smaller — suggesting there is less damage in the arteries and heart. Additionally, midday sleepers had greater dips in blood pressure during the night (which is a good thing), and they took fewer antihypertensive medications.

Longer naps were better than shorter.

The research was presented at the 2015 ESC Congress.

http://www.eurekalert.org/pub_releases/2015-08/esoc-mna082815.php