Daytime Nap Alleviates Adverse Effects of Stress

Sleep confers restorative effects to mental, emotional, and physical health.  With the average sleep duration is now almost 2 hours shorter per night than it was 50 years ago, sleeping less has been linked to an increased risk of hypertension and cardiovascular problems generally.  Ryan Brindle, from Allegheny College (Pennsylvania, USA), and colleagues report that a daytime nap confers cardiovascular benefits.  The researchers split 85 healthy university students into two groups: One group was allotted a 60-minute interval during the day when they had the opportunity to sleep; the other group did not sleep during the day. The researchers also asked the students to complete questionnaires assessing sleep quality and complete a cardiovascular reactivity task, involving a complex mental subtracting exercise. The team measured the students’ blood pressure and pulse rates at regular intervals throughout the experiment, finding that daytime sleep seemed to have a restorative effect:  students in the sleep condition reported  lower scores of sleepiness, as compared to than those who did not sleep. Although blood pressure and pulse rates rose in both groups between baseline and the stress phase, during the recovery phase, those who had napped had significantly lower average blood pressure readings than those who had not slept. These results show that sleeping between 45 and 60 minutes during the day appears to facilitate blood pressure recovery after a mental stress task in the laboratory.  Observing that: “These findings suggest daytime sleep may offer cardiovascular benefit in the form of greater cardiovascular recovery from psychological stress,” the researchers urge further research “to better understand its role as a possible recuperative agent against suboptimal nocturnal sleep patterns.”