London, Aug 30: Taking midday naps may reduce your blood pressure and lower the risk of a heart attack, a new study has claimed.
"Winston Churchill said that we must sleep sometime between lunch and dinner while Margaret Thatcher didn't want to be disturbed at around 3:00 pm," said Manolis Kallistratos, a cardiologist at Asklepieion Voula General Hospital in Greece.
"According to our study they were right because midday naps seem to lower blood pressure (BP) levels and may probably also decrease the number of required antihypertensive medications," said Kallistratos.
The study included 386 middle aged patients (200 men and 186 women, average age 61.4 years) with arterial hypertension.
The researchers measured 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 per cent 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 per cent lower when they were awake (5 mmHg) and 6 per cent lower while they slept at night (7 mmHg) than non-midday sleepers.
"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 per cent," Kallistratos said.
The researchers also found that in midday sleepers pulse wave velocity levels were 11 per cent lower and left atrium diameter was 5 per cent smaller. "These findings suggest that midday sleepers have less damage from high blood pressure in their arteries and heart," said Kallistratos.
Patients who slept for 60 minutes midday had 4 mmHg lower average 24 hour systolic BP readings and a 2 per cent higher dipping status compared to patients who did not sleep midday.
Dippers had an average of 17 minutes more midday sleep than non-dippers. "Our study shows that not only is midday sleep associated with lower blood pressure, but longer sleeps are even more beneficial," Kallistratos said.
"Midday sleepers had greater dips in blood pressure while sleeping at night which is associated with better health outcomes.
"We found that midday sleep is associated with lower 24 hour blood pressure, an enhanced fall of BP in night, and less damage to the arteries and the heart," Kallistratos said.