Naps Help Relieve Stress

Summary
Studies have shown that sleep deprivation and inadequate or low quality sleep increases death and disease due to heart ailments. This study attempted to explore the effects that daytime napping had on heart diseases. Results showed that a 45- to 60-minute nap during the day could lead to lower blood pressure. Authors conclude that, “These findings suggest daytime sleep may offer cardiovascular benefit in the form of greater cardiovascular recovery from psychological stress.” They suggest further studies to explore the effects of time and the duration of daytime naps on heart disease outcomes.

Introduction
There is a rising occurrence of inadequate nighttime sleep in people. This is mainly due to longer working hours and work stress mounting to unmanageable levels. Other contributing factors include the rise of depression and anxiety-related disorders and increased use of television and the Internet late at night. Studies have shown that on an average there is a 1.5 to 2 hours sleep deprivation per night in most individuals when compared to people five decades ago. Studies have linked this lack of sleep with the risk of high blood pressure and heart diseases. There is evidence that teenagers as well as adults are at increased risk of heart diseases due to any type of psychological strain. This study explored how daytime naps affect recovery from psychological stress and in turn predict risk of heart disease.

Methodology
* Participating in the study were 85 healthy volunteers with an average age of 20. They were examined before the experiment and their blood pressure and other heart-related parameters were noted.
* They were then divided into two groups. One group was allowed to sleep for an hour during the daytime. The depth and details of their sleep was monitored by an instrument called the polysomnograph. This excluded those who did not actually sleep. The other group did not get any sleep during the daytime.
* At the end of the hour all participants were given three phases of mental arithmetic tests to mimic stress. Throughout the stressful situation their pulse and blood pressure were monitored.

Results/Key findings
* During initial screening after the nap, it was noted that the sleep group felt less sleepy than the no-sleep group. This was assessed by a sleep questionnaire.
* All participants showed similar rise of pulse and blood pressure when subjected to the stressful situations.
* Analysis showed that a daytime nap of around 45 minutes to an hour could significantly improve the reduction of blood pressure and return it to baseline after a stressful situation.

Next steps/Shortcomings
Authors admit some shortcomings. One of these is the small sample of study population. They write that they did not examine the exact time of the daytime nap and its relative efficacy to the results obtained. They suggest that their hypothesis — a longer duration of daytime nap could improve heart conditions due to stress — is too broad and needs further detailed exploration.

Conclusion
This study shows that daytime naps improve the recovery of the heart from stress. This recovery is linked to better cardiovascular health. It actually connects the two lines of thoughts; first, inadequate sleep leads to higher heart disease risk, and second, delayed recovery after a stressful situation can predict the risk of heart disease. With more people who are sleep deprived these days, this study is especially significant. An important finding is that not feeling sleepy while in a stressful situation might help bring down blood pressure to normal quickly after the situation has ended. Authors suggest that further studies are needed to look into the exact duration, structure and timing of the daytime naps that can help reduce the risk of heart disease.

For More Information:
Daytime Sleep Accelerates Cardiovascular Recovery after Psychological Stress
Publication Journal: International Journal of Behavioral Medicine, February 2011
By Ryan C. Brindle; Sarah M. Conklin; Allegheny College, Meadville, Pennsylvania

*FYI Living Lab Reports Are Summaries of the Original Research.