Category Archives: Heart Diseases

Valentine’s Day: The Gift of Knowledge for Your Heart and Sleep

In the last few years, there has been an explosion of information linking sleep and heart disease. We have come to understand not only the risks of untreated sleep apnea but also the consequences of insufficient sleep. Every year new studies are published that demonstrate the risks imposed by sleep abnormalities in addition to the mechanisms by which they occur. Here are eight things you should know about the impact of sleep on your cardiovascular health.

1. Sleep apnea has been shown to be a cause of subclinical atherosclerosis. Those with sleep apnea demonstrate both increased thickness and stiffness of the arteries consistent with atherosclerosis.

2. As demonstrated in the Sleep Heart Health Study, cardiac arrhythmias such as atrial fibrillation are four times more likely to occur in sleep apnea. In addition, after electrical cardioversion, those with untreated sleep apnea are twice as likely to go back into atrial fibrillation.

3. Heart attacks: In a recent study published in the International Journal of Cardiology, patients who suffered a heart attack and had their sleep apnea treated were three times less likely to have a recurrence than those who remained untreated.

4. Heart failure: When associated sleep apnea is treated, significant improvement in cardiac function and quality of life is noted. Untreated sleep apnea will result in further loss and injury to the remaining heart muscle and early death.

5. The incidence of sleep apnea in those suffering a stroke or TIA (Transient Ischemic Attack) is 44 – 72 percent in various studies. This is statistically much higher than expected. If untreated, not only is the recurrence rate high, but rehabilitation is impaired.

6. Chronic sleep duration of six hours or less has been shown in a major series of studies called the Penn State Cohort to result in an increased incidence of hypertension and diabetes.

7. Insufficient sleep results in a triggering of the HPA (Hypothalamic Pituitary Axis) and release of mediators of inflammation. These in turn result in an increased incidence of hypertension, atherosclerosis, and heart attack.

8. Children: Obesity in early life promotes atherosclerotic disease in vascular structures such as the aorta and the coronary arteries. Insufficient sleep is a major cause of childhood obesity. In many cases, parents just don’t know how many hours of sleep their children actually need. Take the time to educate yourself. The information is readily available.

Your Heart and Sleep Apnea

It is a common misconception to view sleep apnea as a disease of obese men that leaves them sleepy.  In fact, sleep apnea is a pervasive disorder that results in the dysfunction of many organ systems in our body.  This association appears to be plainly obvious when it comes to heart disease.  The relationship between sleep apnea and heart disease has become better understood in recent years.  We know that over 50% of individuals who have heart attacks have sleep apnea.  We also know that sleep apnea is a leading cause of hypertension–especially when that hypertension fails to normalize using three or more medications.

We know that the cardiac arrhythmias such as atrial fibrillation are much more common in people with sleep apnea.  We also know that failure to diagnose and treat the sleep apnea will, in most cases, result in frequent recurrences of the atrial fibrillation with a very high risk of associated stroke.  In addition, it is not uncommon for people with very slow heart rates detected during sleep to have pacemakers implanted.  Unfortunately, in many of these instances, it was the undetected sleep apnea that was the culprit.

Recent studies have revealed how, if untreated, sleep apnea leads to progressive weakness of our heart muscles.  Actually, in patients with congestive heart failure, detection and treatment of sleep apnea can be lifesaving.  In fact, with treatment of sleep apnea, significant improvement in cardiac function is noted.

These undesirable cardiac disorders are brought about by numerous alterations associated with sleep apnea.  There is the severe elevation in blood pressure while asleep.  Then there are repeated drops in oxygen that result in the release of tissue-damaging oxygen free radicals.  There is also noted to be a release of inflammatory mediators such as CRP (C Reactive Protein) which promote atherosclerosis.  Finally, there are pressure changes that occur in our chest cavities in response to attempting to breathe against a closed airway.  These make it much harder for the heart to pump and lead to further progressive damage.

Accordingly, if you or a loved one might have this disorder, be aggressive about getting it diagnosed and treated.  To ignore it would be the same as ignoring high blood pressure or diabetes.  The consequences of not treating it are just as severe.  In fact, in many instances, the sleep apnea may be the engine driving the high blood pressure and diabetes.

The Afternoon Slump

By Robert Rosenberg, DO

Why is it that so many people complain of sluggishness after lunch?  What is it about this particular time of day that makes some of us so vulnerable to fatigue and sleepiness?  Why is it so common to have trouble concentrating and paying attention during this period?  It really has to do with a balancing act between our intrinsic biorhythms and our environment.

As soon as we awaken, the pressure to fall asleep gradually develops in the form of a sedating neurochemical called adenosine.  In fact, caffeine works in part by blocking the actions of adenosine.  This buildup during the day is competing against the actions of our normal circadian alerting system that resides deep in the part of our brain called the suprachiasmatic nucleus.  There is usually a balance between the two forces and we are alert.  As the day progresses, adenosine levels peak and the alerting system tapers, resulting in sleepiness.

However, there are some time warps in this nice balance.  Most of us experience a dip in our alerting system between 2 – 4 p.m.  Our body temperature drops slightly and this can set in motion feelings of sleepiness and fatigue.  If we then add into the mix a prior night of poor quality or quantity of sleep, it becomes almost impossible to avoid feeling sluggish and drowsy.

Diet also plays a large part in the equation.  If we eat a lunch high in simple carbohydrates, we set into motion rapid rises in insulin levels.  This can result in more of the amino acid tryptophan getting into the brain.  Tryptophan is converted to serotonin and then melatonin, resulting in sleepiness.

In addition, having a large meal can divert blood flow from the brain to the intestinal tract.  It will also activate the parasympathetic nervous system and suppress the sympathetic (fight or flight) system.  This can result in a feeling of low energy and result in a desire to sleep.

So what can we do to counter this afternoon slump?

*We can take a short nap of 15 to 20 minutes.  In Spain they call it Siesta.
*We can ensure that we get enough quality sleep at night.
*We can change our midday meal to a smaller one.
*We can add more protein and substitute complex carbohydrates for simple ones.
*We can get some exercise by taking a brisk 10 minute walk after lunch.  Exercise can have a definite alerting effect on our minds and bodies.

The bottom line is to become more aware of our intrinsic biorhythms and those factors that can affect them.

 

Dr. Rosenberg wrote this article for Everyday Health
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