My last sharepost discussed how obstructive sleep apnea affects heart disease. Hypertension and heart disease frequently occur together, but that’s not always the case. So let’s talk specifically about hypertension and obstructive sleep apnea.
A relationship between hypertension andobstructive sleep apnea has been backed by a large amount of scientific data, and it has been confirmed with the latest large study known as the Sleep Heart Health Study. Carried out by the National Heart, Lung & Blood institute, this study determined cardiovascular and other consequences of sleep-disordered breathing.
Over 6,000 men and women ages, 40 and over, were enrolled in the study. Each person and was screened with two sleep studies, three years apart.
For those with a new onset of OSA, the study found a definite association with hypertension. For those with pre-existing hypertension (existing before being enrolled in the study), researchers found that OSA would become more resistant to treatment.
Based off of the studies, experts believe that these results have to do with the abnormal breathing events that take place during sleep with OSA, all beginning with how sleep affects our nervous system. The autonomic nervous system, working without our control, is made up of two systems that typically work against each other to balance metabolic or physiologic processes in the body. For example, when you experience an adrenaline rush, one of the systems will work in the body to tighten the arteries, causing a rise in blood pressure and increase your heart rate, then the other will work to create the opposite effect to bring them back to normal.
During sleep, blood pressure, heart rate, and respiratory rate and deepness of breath all normally decrease. These phenomenon all occur as an effort to conserve energy and to direct the energy to the most active organ during sleep, the brain. However, when there is an obstructive apnea event (a blockage in the throat and increased effort by the diaphragm to overcome the resistance), there is a surge in body activity. This results in elevation of the blood pressure.
Studies have shown that this activity can persist, even during wakeful hours when there are no apnea events. The result is persistent elevated blood pressure. Very commonly, this elevated blood pressure is more resistant to treatment and requires more medications and higher therapeutic doses.** The Sleep Heart Health Study concluded that obstructive sleep apnea is an independent risk factor for hypertension,** after controlling the data for other factors such as weight, age and smoking. This means that the risk for hypertension is higher when you have obstructive sleep apnea, regardless of whether you have the other risk factors. Even if the blood pressure is normal during sleep, instead of lower than normal as it should be, that “normal” is still dangerous to heart function. Patients with this type of hypertension are called “non- dippers” because their blood pressure doesn’t drop lower (dip) during sleep.
The good news is that this resultant hypertension can be reversed with treatment of the obstructive sleep apnea with CPAP. Once again, this positive outcome is based on identifying these individuals with a proper sleep study and then prescribing therapy.The Joint National Committee (JNC) which is the national organization that sets the guidelines for managing hypertension has added OSA (obstructive sleep apnea) as a condition that causes secondary hypertension. This term encompasses all the conditions that cause hypertension which, if treated, will have a curative effect on the hypertension. This is different from essential hypertension which is hypertension that has no known cause.
When dealing with a diagnosis of hypertension, it’s crucial to focus on lifestyle changes which can include improving the quality of your diet and losing weight if necessary, embracing dailyexercise, getting adequate sleep, reducing stress and avoiding any other risk factors for hypertension. You now know that one of those risk factors is obstructive sleep apnea.
Eli Hendel, M.D., is a board-certified internist/pulmonary specialist with board certification in Sleep Medicine. An Assistant Clinical Professor of Medicine at Keck-University of Southern California School of Medicine, and Qualified Medical Examiner for the State of California Department of Industrial Relations, his areas include asthma, COPD, sleep disorders, obstructive sleep apnea, and occupational lung diseases. Favorite hobby? Playing jazz music. Find him on Twitter @Lung_doctor.