How Obesity Increases the Risk of Sleep Apnea

The link between obesity and sleep apnea is not as well-defined as with other ailments, but there is still some evidence that the two conditions are related. Sleep apnea is a relatively common disorder where people might have pauses in breathing or shallow breaths while sleeping. (1) Sleep apnea is extremely disruptive for sleep patterns, because it will move the person suffering from it out of deep sleep into light sleep many times a night. (2) This will result in a quality of sleep that is too poor for good rest, so the patient will feel tired during the day and will cause excessive sleepiness. (3) One of the symptoms of sleep apnea, apart from poor sleep and tiredness, is snoring. (4) This is also known as obstructive sleep apnea and it means that the airway has collapsed or been blocked while the person is asleep, which causes loud snoring as the air tries to move past the blockage. (5) Sleep apnea is a risk factor if it is untreated for a variety of conditions, all of which are related to obesity: high blood pressure, heart attack, stroke, diabetes, heart failure or arrhythmia, as well as work- or driving-related accidents because of tiredness. (6)

Another type of sleep apnea is called central sleep apnea and this is when the respiratory control centers of the brain are disrupted and imbalanced during sleep. (7) This condition can lead to imbalances in blood pressure, low levels of blood oxygen which can cause seizures (unrelated to epilepsy), angina, arrhythmia or even a heart attack. (8) Years and years of central sleep apnea can also cause the pH of the blood to lower through the increase of carbon dioxide causing metabolic acidosis. (9)

Treatments

The frontline treatment for sleep apnea is mostly behavioral therapy. The goal is to change one’s sleeping habits to try to sleep on the side, which can prevent the tongue and palate from falling backwards while sleeping and blocking the airway in the throat. (10)

If you are obese or overweight, losing weight can significantly improve your sleeping habits and make sleep apnea less of an issue or remove the symptoms entirely. (11) This is because the excess body-fat around the neck and throat starts to disappear, allowing more air to pass through the airways. (12) It’s also possible that the thyroid gland, which is responsible for releasing hormones that regulate the metabolism, is affected by excess body-fat, causing it to be larger and potentially block the airways as well.

Most individuals that suffer from sleep apnea are overweight and have large necks that are (collar size over 17” in males or 16” in females). (13) Weight reduction, avoiding alcohol and sedatives, medications to stimulate the respiratory center of the brain, CPAP masks that force the airway to stay open, jaw positioning devices and finally, surgery to remove any obstructions of excess body-fat in the airways are all methods of dealing with and treating sleep apnea in both its forms. (14)

From most of the available studies, it is quite clear that sleep apnea is related to obesity, due to the fact that 95% of people suffering from sleep apnea are obese. (15) However, there is still no direct proof that obesity can actually cause sleep apnea and the mechanism is largely not understood. (16) The mechanism seems to work largely through the mediation of atrial fibrillation (arrhythmia), because obesity causes atrial fibrillation and atrial fibrillation is associated with obstructive sleep apnea. (17)

The relationship to daytime sleepiness and fatigue

Sleep apnea also comes hand in hand with daytime sleepiness and fatigue. All three of these issues are extremely common in obese middle-aged men. (18) Additionally, this study found that both cytokines (protein released by body-fat and responsible for pain regulation) and leptin (protein released from body-fat to regulate appetite) were also found to be in very high levels in patients who were obese and had sleep apnea. (19) Since the presence of high levels of these two substances in the body has been firmly associated with obesity and the metabolic syndrome in general, it can be said that sleep apnea is probably another of the many conditions that make up the metabolic disorders that are related to obesity. Furthermore, the blood glucose levels of obese patients were much higher than in regular weight ones and this was related to insulin production in the body as well, giving sleep apnea another strong relationship to the metabolic syndrome. (20) In all these cases, a clear association was made between sleep apnea and the levels of the substances. They were not directly related to obesity itself, but were indeed related to sleep apnea. (21) And because we know that obesity is related to high levels of these substances, a case can be argued that sleep apnea could possibly cause obesity, or vice versa. Finally, sleep apnea in obese middle-aged men was definitely associated with “visceral obesity, inflammatory cytokine elevations, hyperleptinemia, and hyperinsulinemia.” (22)

Weight reduction

Reduction of weight has definitely been associated with the reduction in the severity of sleep apnea symptoms. (23) Additionally, weight loss can also reduce hypertension and improve renal function associated with sleep apnea as well. (24) Most studies have shown that even a 10% reduction in weight can have a massive, 50% reduction in the severity of sleep apnea. (25) This indicates that there is some sort of a “threshold” effect in relationship to this condition and that reducing body-weight is one of the most effective ways to significantly reduce or even arrest the symptoms of sleep apnea completely. In addition to this, reducing body-weight can improve cardiovascular conditions which can reduce the chances of suffering from heart attacks or arrhythmia, both of which can come about through suffering from sleep apnea. (26)