More research links high blood pressure and sleep disorders.
Normally, sleep is a relatively calm and restorative period for the cardiovascular system. Blood pressures drops by an average of 15 points, referred to as nocturnal dipping, and the heart doesn’t need to work as hard. However, more research is linking high blood pressure with sleep disorders.
There are two studies published this year in the journal Sleep Medicine that demonstrate the link between sleep and hypertension. In the first, titled Epidemiological Evidence for the Link Between Sleep Duration and High Blood Pressure, the authors reviewed 21 studies involving 225,000 subjects. They found that short sleepers, as defined by sleeping less than six hours a night, were 20 percent more likely to develop hypertension.
In a second study published recently, titled Poor Sleep Quality and Resistant Hypertension, 270 patients in a hypertension clinic in Italy were studied. They found a high prevalence among those with resistant hypertension, especially women, of poor sleep quality ― an inability to fall asleep or increased time in bed without sleeping.
Several other studies have linked sleep apnea to hypertension ― especially resistant hypertension. Spanish researchers recently studied sleep apnea patients who were also taking three or more drugs to lower their blood pressure. They found that those who used the Continuous Positive Airway Pressure (CPAP) device for 12 weeks reduced their diastolic blood pressure and improved their overall nighttime blood pressure. CPAP is the standard treatment for sleep apnea. Since the prevalence of sleep apnea in patients with resistant hypertension is very high, lead researcher Dr. Miguel-Angel Martinez-Garcia, from the Polytechnic University Hospital in Valencia, suggests that patients with hard-to-control high blood pressure should undergo a sleep study test to see if they have a sleep disorder. By treating the latter, their blood pressure may drop.
Sleep Medicine Consultant and medical writer Dr. Robert Rosenberg, DO explains that “the common denominator in sleep disorders is activation of the bodies stress systems during sleep – a no-no for good cardiovascular health. Several studies have shown that those with sleep apnea and insomnia, especially those who sleep less than six hours, activate the two major stress systems – the HPA (Hypothalamic Pituitary-Adrenal system) and the Sympathomedullary system. This results in the release of cortisol and adrenaline, both of which are OK on occasion in small doses, especially when facing stressful situations. However, their continued release all night every night is not. Eventually, it can lead to sustained and very difficult to treat hypertension.” Dr. Rosenberg is also Medical Director in Northern Arizona of The Sleep Disorders Centers of Prescott Valley and Flagstaff. Continuous positive airway pressure (CPAP) is the standard treatment for sleep apnea, a condition characterized by disrupted breathing during sleep.
He says that it is important to be aware of sleep and its effect on one’s blood pressure. In the case of resistant hypertension, the odds of having a sleep disorders is in more than 60 percent. “The good news,” he adds, “is that with treatments such as CPAP for sleep apnea or cognitive behavioral therapy for insomnia, significant improvement in blood pressure can be achieved.”