Results of one of my summer research projects with a group of students here at Allegheny College, was recently published in the International Journal of Behavioral Medicine. Our data suggest that sleeping for up to an hour during the day could facilitate cardiovascular recovery after mental stress.
Our study, examined the effect of a daytime nap on cardiovascular recovery following a stress test. We found that participants who slept for at least 45 minutes during the day had lower average blood pressure after psychological stress than those who did not sleep.
Long work schedules, shift work, increased anxiety and a greater use of the internet and television late at night - all characteristics of our modern society - have had an impact on nocturnal sleep. We no longer sleep as long as we used to: The average sleep duration is now almost 2 hours shorter per night than it was 50 years ago. And this could be impacting our long-term health. For example, sleeping less has been linked to an increased risk of hypertension and cardiovascular problems generally.
In our paper we examined how daytime sleep might influence cardiovascular recovery after a mental stress test in the laboratory. We split 85 healthy college 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. We asked the participants to complete a cardiovascular reactivity task, involving a complex mental subtracting exercise which has been used in research before. Our research group measured the students' blood pressure and pulse rates at regular intervals throughout the experiment.
We found that daytime sleep seemed to have a restorative effect with participants in the sleep condition reporting lower scores of sleepiness than those who did not sleep and those who had napped had significantly lower average blood pressure readings than those who had not slept. Our findings suggest that daytime sleep may offer cardiovascular benefit by accelerating cardiovascular recovery following mental stressors.
Allegheny students who are interested in sleep and health research should discuss these opportunities with Dr. Conklin! A number of follow-up studies are in the works.