Tag Archives: high blood pressure

It’s good to breathe

Obstructive sleep apnea can be quite dangerous when not treated.  Restricted airflow which occurs repetitively in individuals with sleep apnea stresses the body in several ways.  We know that people who suffer from obstructive sleep apnea have a higher risk of high blood pressure, stroke, irregular heart rhythms, elevated blood glucose levels, car accidents and even sudden cardiac death.  In addition, people with sleep apnea often feel tired, complain of non-restorative sleep and have a poor quality of life.  Having untreated sleep apnea does not necessarily mean that an individual will ever suffer these ailments, but it does raise the risk.   The more severe the sleep apnea, the higher the likelihood of ever suffering from one of these entities.

Untreated sleep apnea results in these ill effects for two main reasons.  First of all, the oxygen levels dip which stresses the body. The second reason is that sleep apnea results in fragmented and poor quality sleep.

When people don’t breath well at night,  oxygen levels repetitively dip resulting in bodily stress.  As most people are aware, our body tissues need adequate oxygen for optimal function.  It can thought of as a stress test every night.  When a person’s upper airways narrow, airflow is limited and oxygen levels drop.    Most people’s oxygen levels remain at 97-100%.  Associated with apnea events, oxygen levels drop by at least 3%.  It is not uncommon for oxygen levels to drop even further.  Individuals with severe sleep apnea commonly have drops of their oxygen levels into the 70-80% range.  I have seen patient’s with oxygen levels dipping into the 50s%!     When the tissues are starved of adequate oxygen, the risk of heart attack and stroke increases.  The sympathetic nervous system is activated which results in elevated blood pressures with frequent surges in blood pressure and heart rate.   In addition, inflammatory mediators are released which can further damage tissues.

Sleep apnea also results in fragmented  and poor quality sleep.  After a good night’s sleep, a person should feel refreshed and ready for a full day’s activities.  Optimal sleep should last 7-8 hours in adults during which a person cycles through stages of sleep.   There should be 3-4 sleep cycles during which a person transitions from light sleep, to deep sleep and then into REM sleep.  We call this sleep architecture.  Each stage of sleep is associated with important bodily functions like memory consolidation, hormone secretion and clearing of accumulated waste products.   If an individual’s sleep is disrupted by sleep apnea, sleep architecture becomes fragmented and the full benefits of sleep are not achieved.  The breathing events associated with sleep apnea frequently cause arousals.  Essentially, arousals are ‘brain awakenings’ which disrupt sleep architecture.    For example, a person with moderate or severe sleep apnea will commonly have more than 15 arousals per hours which prevents them from entering the restorative stages of sleep such as deep sleep.  This is why a patient with sleep apnea will commonly state that they never feel like they slept.

Indeed, it is good to breathe.  This article explains why obstructive sleep apnea leads to an increased risk of cardiovascular problems, as well as excessive daytime sleepiness.