A study published in July 2014 reported that after a stressful event (marital separation, in this case), difficulties sleeping didn’t quite correlate with current blood pressure but did predict future elevations of blood pressure. The authors of the study speculated that the stress of the separation caused poor sleeping which ultimately led to elevated blood pressure- which may in turn be the primary cause of the increased morbidity and mortality seen in individuals who undergo very stressful life events. Individuals with hypertension over time experience significant damage predominantly to the vascular system, eyes, kidneys – and are much more likely to develop heart disease and die prematurely.
The link between poor sleep and elevated blood pressure has been observed previously. A systematic review published in 2013 pooled the evidence from 24 different studies and reported that individuals who sleep less than 6 hours per night on a regular basis are much more likely (20% higher risk) to develop hypertension than better-rested individuals. Other studies have found that interventions to extend and improve sleep, such as treating sleep apnea, can reduce blood pressure.
The Common Link is Stress
The causal connection may involve stress. During restorative sleep, healthy individuals relax. Their blood pressure drops by at least 15 points. The heart slows down. The whole system relaxes and resets. If an individual is stressed sufficiently to disrupt sleep, this nightly period of relaxation doesn’t occur.
There are two primary stress pathways in the body, the hypothalamic pituitary-adrenal system and the sympathomedullary system. When an individual experiences stress, these systems activate and secrete adrenaline and cortisol into the body. Being stressed for short periods of time is not harmful. However, if the stress is chronic and prolonged, the body continues to operate in stress mode all day and more devastatingly, all night. If the stress continues long enough, it will cause chronic hypertension to develop.
An immediate clinical application of these findings is the approach to treating hypertension. Most individuals who develop hypertension are typically encouraged to pay attention to their diet and exercise regimen, and in some instances given medication. However, a certain percentage of individuals who develop hypertension don’t respond to any of these conventional treatments- they are referred to as “treatment-resistant hypertensives”. Studies of the connection between sleep and high blood pressure has revealed that 60% of treatment-resistant hypertensives have some kind of sleep disorder, and treating the sleep disorder will also correct the high blood pressure.
Individuals who develop high blood pressure may now have another avenue of lifestyle modification to explore before trying medications. Along with a good diet and exercise plan, make more time for restful sleep. In some individuals a physician may consider a sleep study done to see if there is some kind of sleep disorder going on. What is even more insteresting is that many individuals with sleep apnea are unaware they have the condition. Other individuals troubled by insomnia have never bothered to seek treatment for their condition. However, now that we know that poor sleep leads to hypertension, we understand a lack of good sleep is a serious, potentially fatal condition and it needs prompt medical attention.
Apparently maintaining good heart health isn’t just about exercise, proper diet, and taking the right kind of vitamins for the heart, it’s also about getting a good night’s sleep.