Sleep apnea refers to a condition in which a sleeping individual stops breathing. Eventually, due to physiologic factors such as a drop in the oxygen saturation of the blood, the brain rouses the individual (usually only partially) and breathing resumes. The severity of the sleep apnea is gauged by how often these episodes occur, how long each one lasts, how much the blood oxygen level drops and other factors. In severe cases, this may occur hundreds of times per night leading to extremely fragmented and abnormal, non-restorative sleep. This results in a state of chronic fatigue along with all the medical issues described in part 1.

There are 3 types of sleep apnea: OBSTRUCTIVE, CENTRAL AND COMPLEX.

OBSTRUCTIVE SLEEP APNEA (OSA) is the most common type of sleep apnea.  It describes the obstruction of the airway by the tongue and soft palate during the deeper stages of sleep in susceptible individuals.

CENTRAL SLEEP APNEA is due to the brain failing to signal breathing, even though the airway is open.

COMPLEX SLEEP APNEA is a combination of the above types.

The following signs and symptoms may be related to non-restorative sleep due to sleep apnea. Anyone displaying one or more to any significant degree should have a sleep study.

Although being overweight or obese (BMI over 35), or having a large neck circumference (16” or more in females and 17” or more in males) do not predict sleep apnea in and of themselves, they are often associated with sleep apnea particularly in individuals with any of the above listed signs or symptoms.

There are several methods available to successfully treat sleep apnea. Not all are effective in every individual. These include oral appliances, CPAP (continuous positive airway pressure) machines, Surgery and others. In all cases, weight loss is important if the individual is overweight. In many cases, no other treatment is required.

Any individual who has suffered significant sleep apnea and been successfully treated will describe how good it was to once again feel “normal” and energetic. In addition, many medical problems such as high blood pressure resolve with no further need for medication.

All of us want to sleep well, feel well, and function at our best. Individuals who have safety-sensitive occupations upon which the welfare of others depends (such as pilots, air traffic controllers, etc.) have a moral, ethical and legal obligation to ensure they are fit to perform their duties. This concept is often referred to as "Self-assessment". I would urge any individual who believes they may suffer from sleep apnea to seek the advice of a sleep specialist.

For further information click here.

Sleep well, be well.

E.A. Mastrangelo, M.D.

We need to sleep. Everyone knows this instinctively. It is important to everyone and is critical for people in safety sensitive occupations....such as pilots.

It has been relatively recent that medical science has begun to study sleep in an in-depth fashion. This may be in part due to the fact that few adequate research tools were available to do this type of research. Most studies were of an observational nature or studied changes in blood chemistry. New tools are now available (such as neuro-imaging) and hold promise with respect to enhancing our knowledge in this area.

Numerous questions still exist. Why is sleep important? What function(s) does sleep serve? What ill effects will occur as a result of sleep deprivation? Why do some individuals tolerate sleep deprivation better than others? How do medications and what we eat and drink affect sleep architecture? And many more.

I suppose the place to start is with the basic question "Why do we need to sleep"? The following is taken from an article of the same title found in the MedSleep newsletter,  "Sleep Matters" (Volume 4.1) 

The multiple Hypotheses proposed to explain the function of sleep reflect our incomplete understanding. It is likely that sleep evolved to fulfill some sort of primitive function and has taken on multiple functions over time. Animals are most vulnerable when they are asleep. Evolution moves to minimize vulnerability. This would argue that sleep remains an essential physiologic process across all species.

 These hypotheses include:

GROWTH AND RESTORATION (bodily growth and development in children, and tissue repair and restoration in adults) 
ONTOGENESIS (development of an organism from the earliest stage to maturity)
MEMORY PROCESSING (allows solidification of knowledge and memory)
WASTE CLEARANCE (clearance of metabolic waste products produced by neural activity of the awake brain).

For further reading and information about MedSleep click here 

Normal sleep is divided into 2 main stages--NREM (non rapid eye movement) and REM (rapid eye movement) sleep. NREM sleep is further divided into 4 stages--stages 1 through 4, each being a progressively deeper state of sleep such that progressively stronger stimuli is needed to wake someone from each stage. The stages are defined based primarily on the appearance of the EEG (electroencephalogram) in each stage.

Normally, NREM sleep occurs first, progressing through stages 1 to 4, and REM sleep follows. This cycle repeats itself 4 or 5 times during an 8-hour sleep period. With each cycle, the amount of time spent in REM sleep increases from perhaps 10 minutes or so in the first cycle to 60 minutes or more in the last cycle.

Sleep is a state of unconsciousness in which the brain is relatively more responsive to internal than external stimuli. It was once thought to be a passive state, but we now know (thanks to neuro-imaging technology) that it is a very active and vital state, absolutely necessary for the maintenance of health in every sense of the word.

This is an area of intense clinical research with numerous published studies. Sleep deprivation is not only detrimental to health, it can be fatal. Studies with rats have shown that total sleep deprivation resulted in death in a matter of weeks or months. The rats also lost weight despite eating more than the control group. They developed sores on their tails and paws indicating a failure of the immune system. (Sleep 1989 Feb:12(1):13-21). True, people are not rats. But numerous human studies have demonstrated a plethora of adverse effects associated with sleep deprivation in all areas: physical, mental and emotional.

In Part 2, I will discuss sleep apnea. In recent years this condition has received much attention in both the medical literature and the lay press....with good reason. It has been linked to all the adverse health conditions associated with sleep deprivation mentioned above. In addition, it has been implicated as the cause of numerous accidents...in the air, on the road, and in the workplace.

Sleep well.....Be well.
Armando

As a medical student I was taught many "facts" which have since proven to be false. Among them was the "fact" that "a calorie is a calorie is a calorie". Which is to say that, if a body consumes more calories than required, irrespective of the source of those calories (i.e. fat, protein, or carbohydrate), that body will accumulate fat. We know now that this is not exactly true.

The preferred energy source for the human body is glucose. Sugar. Other substances can be converted to energy, but not as efficiently. Glucose is readily obtained from all carbohydrate sources. These include most types of sugar (i.e. granulated sugar, fruit sugar (fructose), milk sugar (lactose) etc.) and all grains, root vegetables and other sources. Carbohydrate will not be wasted. Any excess is stored, first in the form of glycogen in liver and muscle cells, and then as fat.

The storage capacity for glycogen in liver and muscle is fixed and only enough to last a few days. The fat "tank", on the other hand, is remarkable in that its capacity to expand is almost limitless. The fat cell is called an adipocyte. Its precursor is called a pre-adipocyte. Pre-adipocytes have the ability to multiply and make more fat cells. When the fat cells are full, pre-adipocytes multiply and make more. So the storage facility continues to enlarge. In order for storage to occur, the hormone insulin must be present. In general, the more insulin present, the greater the amount of storage (fat).

For most of humankind's evolutionary history, the ability to store fat conferred a survival benefit during periods of famine. In modern times, however, with the availability of carbohydrate dense food 24/7, 365 days a year, this benefit is lost. Instead, it has created the so called "obesity epidemic" with all its associated medical conditions, morbidity and mortality.

Limiting the carbohydrate intake to below the individual's daily energy requirements forces the body to use its energy stores. First the glycogen in liver and muscle is used. This lasts only a few days. Less if the individual exercises. When the glycogen is used up, fat stores are utilized. Fat will continue to be burned 24/7 as long as the carbohydrate intake is below daily requirements.

Replacing the carbohydrate with non carbohydrate food does not significantly affect the fat loss. Animal fat, saturated fat (bad fat) intake is discouraged since it can adversely affect lipid levels, insulin sensitivity and cause other problems. Intake of "good fats" such as omega-3, omega-6 and olive oil, in moderate amounts is beneficial. 

Protein intake does not result in blood sugar elevation or accumulation of fat. If an individual alters their diet in such a manner that carbohydrate is reduced to below daily requirements and replaced by pure protein, weight (fat) loss will occur. This is true even if the total calories in the protein is greater than the carbohydrate calories would have been. It appears, therefore, that when it comes to how the human body utilizes energy sources, a calorie does NOT equal a calorie.

There are many low carbohydrate diets on the market. Each has its own biases, but carbohydrate reduction is key in all of them.

No diet should be undertaken unless your physician approves and monitors it. All diets, including low carbohydrate diets can be dangerous if an individual has certain medical conditions. For example, a low carbohydrate diet may be dangerous for diabetics on oral medication and/or insulin. It would require very close monitoring by a physician, and may be totally inappropriate in some cases. Other medical conditions must also be excluded before an individual is started on a low carbohydrate or any other type of diet.

Stay well. Stay safe.

Armando

E. A. Mastrangelo M.D. CAME, AME