A new study finds that daytime napping has a positive effect on blood pressure and lowers the need for anti-high blood pressure meds.
As the New Zealand Herald reports:
The study included 386 people with raised blood pressure who were aged 61 on average. After adjusting for other health factors that might influence the results, it found nappers had a four per cent lower blood pressure reading when awake and a six per cent lower reading while they slept at night than people who did not nap. Dr [Manolis] Kallistratos [project lead and a cardiologist at Asklepieion Voula General Hospital in Athens] said although the reductions seem low, even modest reductions can cut the risk of cardiovascular events, such as heart attack and stroke, by up to 10 per cent. “Our study shows that not only is midday sleep associated with lower blood pressure, but longer sleeps are even more beneficial,” he said. “Midday sleepers had greater dips in blood pressure while sleeping at night, which is associated with better health outcomes.”
We can add this to an already-long list of benefits of afternoon naps. 
For those who really want to geek out on the details, here’s a summary from AAAS’s EurekAlerts:
The study included 386 middle aged patients (200 men and 186 women, average age 61.4 years) with arterial hypertension. The following measurements were performed in all patients: midday sleep time (in minutes), office BP, 24 hour ambulatory BP, pulse wave velocity, lifestyle habits, body mass index (BMI) and a complete echocardiographic evaluation including left atrial size. BP measurements were reported as diastolic and systolic BP.
After adjusting for other factors that could influence BP such as age, gender, BMI, smoking status, salt, alcohol, exercise and coffee, the researchers found that midday sleepers had 5% lower average 24 hour ambulatory systolic BP (6 mmHg) compared to patients who did not sleep at all midday. 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 (Figure 1).
Dr Kallistratos said: “Although the mean BP decrease seems low, it has to be mentioned that reductions as small as 2 mmHg in systolic blood pressure can reduce the risk of cardiovascular events by up to 10%.”
The researchers also found that in midday sleepers pulse wave velocity levels were 11% lower and left atrium diameter was 5% smaller. “These findings suggest that midday sleepers have less damage from high blood pressure in their arteries and heart,” said Dr Kallistratos.
The duration of midday sleep was associated with the burden of arterial hypertension. Patients who slept for 60 minutes midday had 4 mmHg lower average 24 hour systolic BP readings and a 2% higher dipping status5 compared to patients who did not sleep midday. Dippers had an average of 17 minutes more midday sleep than non-dippers.As he notes elsewhere, “Μidday sleep is a habit that nowadays is almost a privileged due to a nine to five working culture and intense daily routine.” But if you want to be healthier (not to mention have improved mood, be more creative, etc.), returning to the habit of a midday nap would be one way to reach that goal.