May 8, 2012
The benefits of napping
With age come changes in the structure and quality of our sleep. After about age 60, we have less deep (slow-wave) sleep and more rapid sleep cycles, we awaken more often, and we sleep an average of two hours less at night than we did as young adults. It was once thought that older people didn’t need as much sleep as younger ones, but experts now agree that’s not the case. Regardless of age, we typically need seven-and-a-half to eight hours of sleep to function at our best. So if you’re not getting enough sleep at night, what about daytime naps? Or does napping disrupt the sleep cycle, ultimately yielding less sleep and more daytime drowsiness?
These questions were addressed in a recent study by researchers at the Weill Cornell Medical College in White Plains, N.Y., and published in the Journal of the American Geriatrics Society (February 2011). The authors concluded that napping not only increases older individuals’ total sleep time—without producing daytime drowsiness—but also provides measurable cognitive benefits.
The study. This small but well-designed study involved 22 healthy women and men ages 50 to 83 who agreed to be evaluated in a sleep laboratory. During a one- to two-week preliminary period, participants kept sleep logs at home and wore monitors to track their nighttime movements. They were then brought into the sleep laboratory for three nights and two days and given a thorough sleep evaluation (using polysomnography and other techniques) and a battery of cognitive tests. After this initial laboratory session, participants started a month-long daily napping routine at home: half took short (45-minute) naps, and half took longer (two-hour) naps. After the second and fourth weeks, all returned to the lab for repeat assessments.
The results. By study’s end, total sleep time had increased by an average of 65 minutes in the participants assigned to two-hour naps, and by an average of 20 minutes in those assigned to 45-minute naps. Participants found it harder to adhere to the two-hour nap schedule, but neither long naps nor short naps disrupted nighttime sleep or led to daytime sleepiness. Napping increased the time spent in slow-wave and rapid-eye-movement (REM) sleep, which are thought to play important roles in restoring the body and brain. Whether they took long naps or short naps, participants showed significant improvement on three of the four tests in the study’s cognitive-assessment battery.
Limitations and implications. Only people in good physical and mental health were included in the study, so it’s unclear whether a 45-minute or two-hour napping regimen would be as helpful to older adults with sleep disorders or medical conditions. The study tells us nothing about the effects of shorter naps (for example, so-called power naps) on waking function. Moreover, the study was brief: napping-related cognitive function was measured after only two weeks and four weeks. Whether the improvements observed during the study would continue during subsequent weeks of napping is not known. Nevertheless, the findings provide further evidence that for older people, a daily nap can add to total sleep (as well as time in restorative sleep) and improve daytime function.
Can allergies cause high blood pressure?
Q. I have allergies. Could they be the reason I have high blood pressure?
A. Although allergies don't usually directly increase blood pressure, they can contribute indirectly to high blood pressure in two very different ways.
Decongestants commonly used by people with allergies, such as pseudoephedrine (Sudafed, Actifed, others) and phenylephrine (Sudafed PE), constrict small blood vessels in the nose. Although this eases nasal congestion and improves breathing, the effect isn't limited to the nose. Constricted blood vessels throughout the body mean the heart must work harder to pump blood. This increases blood pressure. If you take an over-the-counter allergy product, look for one that doesn't contain pseudoephedrine or phenylephrine. Antihistamines such as cetirizine (Zyrtec), chlorpheniramine (Chlor-Trimeton), diphenhydramine (Benadryl), and loratadine (Claritin) can help with the congestion that accompanies allergies and are safer for the heart. Another option is to use a nasal spray, which acts directly on the blood vessels in the nose and has less impact elsewhere in the body.
If your allergies cause nasal congestion at night, they could interfere with your breathing when you sleep. This can promote, or worsen, the type of gasping-for-breath snoring known as sleep apnea, which can raise blood pressure. If you often wake up at night, or if your sleeping partner has noticed that you snore and sound like you choke or gasp for air every so often, talk with your doctor about being checked for sleep apnea.
— Thomas Lee, M.D.
Editor in chief, Harvard Heart Letter