If a good night's sleep helps the brain and body perform better, it's a good guess that sleep problems can cause more than just fatigue. Numerous studies have shown a connection between sleep disorders and medical conditions such as cardiovascular disease, cerebrovascular disease, and metabolic disorders, including the risk of obesity and diabetes mellitus.Sleep and Your HeartSleeping less than seven and a half hours per day may be associated with future risk of heart disease, according to a report in the November 10 issue of Archives of Internal Medicine, one of the JAMA/Archives journals. In addition, a combination of little sleep and overnight elevated blood pressure appears to be associated with an increased risk of the disease."Reflecting changing lifestyles, people are sleeping less in modern societies," according to background information in the article. Getting adequate sleep is essential to preventing health conditions such as obesity and diabetes as well as several risk factors for cardiovascular disease including sleep-disordered breathing and night-time hypertension (high blood pressure).Kazuo Eguchi, M.D., Ph.D., at Jichi Medical University, Tochigi, Japan, and colleagues monitored the sleep of 1,255 individuals with hypertension (average age 70.4) and followed them for an average of 50 months. Researchers noted patients' sleep duration, daytime and nighttime blood pressure and cardiovascular disease events such as stroke, heart attack and sudden cardiac death.
During follow-up, cardiovascular disease was present in 24 percent of the subjects that got less than 7.5 hours of sleep, compared with 18 percent of those with longer sleep duration, according to the authors.
"In conclusion, shorter duration of sleep is a predictor of incident cardiovascular disease in elderly individuals with hypertension," particularly when it occurs with elevated nighttime blood pressure, the authors note.
Sleep and Your Eyes
In the November issue of Mayo Clinic Proceedings, Mayo Clinic researchers outline several interesting associations between sleep disorders and eye disease.
More than 12 million people in the United States have obstructive sleep apnea -- a potentially serious sleep disorder in which breathing repeatedly stops and starts during sleep. Sleep apnea has several types. The most common is obstructive sleep apnea (OSA), which occurs when throat muscles relax and block the airway.
Multiple studies have identified OSA as an independent risk factor for the development of several medical conditions, including high blood pressure, which are related to impairments or alterations in a person's vascular (circulatory) system. With their own complex and sensitive vascular system, the eyes can sometimes signal and be affected by systemic vascular problems.
"Given the vascular consequences of OSA, it is not surprising that ophthalmologic manifestations exist," explains the article's lead author, E. Andrew Waller, M.D., a Mayo Clinic pulmonologist and sleep specialist.The researchers conducted a literature search focused on sleep disorders and eye disease. In the article, they discuss a variety of ophthalmologic conditions associated with obstructive sleep apnea. Highlighted below are a few findings.Floppy eyelid syndrome: This disorder causes eyelids to evert (turn inside-out) spontaneously during sleep, resulting in excessive watering, stickiness, discomfort and blurred vision. While not a serious medical problem, this syndrome can signal that a person also has OSA, which can lead to more significant health problems.Glaucoma: This condition is the second most common cause of blindness and the most common cause of irreversible blindness. OSA is linked to two forms of this disease -- primary open-angle glaucoma (POAG) and normal-tension glaucoma (NTG). The severity of glaucoma appears to correlate with the number and duration of apnea episodes in patients with OSA.Nonarteritic anterior ischemic optic neuropathy (NAION): Research shows an increased incidence of OSA in people diagnosed with NAION. This condition is characterized by the sudden painless onset of vision loss in one eye, often noticed upon awakening. Up to 6,000 patients annually in the United States are diagnosed with this condition, which can cause irreversible vision loss.Papilledema: People with OSA may have a higher incidence of papilledema, swelling of the optic nerve in both eyes. Papilledema typically occurs due to increased pressure within the skull and can lead to progressively worsening vision and, in some cases, blindness."Our understanding of the mechanisms that link these disorders is minimal," says Dr. Waller. However, for patients with OSA, a routine eye examination to evaluate for early signs of glaucoma, particularly in the setting of visual loss or change, is recommended.Sources: JAMA and Archives Journals; Mayo Clinic