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Sleep Apnea and Weight Gain

Sleep Apnea and Weight Gain

  • February 5, 2022

Sometimes, our weight is out of our control. External factors like an illness or your genetic makeup make it to where it feels like the scale is your enemy, even though you are trying your hardest to keep the numbers stable. Sleep apnea is one of those disorders that do just that. This disorder is linked to weight gain and obesity, meaning that it not only affects your sleep but also your weight. But the real question is: how does sleep apnea cause weight gain?

What is sleep apnea?

Sleep apnea is a type of severe sleep disorder in which the airway that enables breaking is partially blocked. This disrupts your breathing pattern, cutting off your air supply for intervals of ten seconds or more throughout the night. This will usually occur multiple times throughout the night. Sleep apnea is relatively uncommon. However, it is more common for men than for women: about 25% of men are affected, while only 10% of women are affected by the same disorder.

Its symptoms include:

  • Gasping for air while sleeping
  • Snoring
  • Exhaustion while you are awake
  • Waking up frequently during the night

There are three different types of sleep apnea: central sleep apnea, obstructive sleep apnea, and mixed or complex sleep apnea.

Central sleep apnea (CSA)

This type of sleep apnea is the least common one with only 0.4% of patients being affected by it. The reason for this type stems from a complication regarding the signals being emitted from the brain to the muscles in your body that are used for breathing. This means that the brain stops and starts repeatedly during sleep, causing the signal telling your muscles to breathe to not be sent. The causes for central sleep apnea are usually complications from an illness, the use of opioids (ex. OxyCotin, fentanyl, heroin), or neurological factors.

Obstructive sleep apnea (OSA)

Obstructive sleep apnea, or OSA, is the most common type of sleep apnea, affecting 84% of patients with the disorder. As opposed to central sleep apnea where the brain shuts off the signals that command the body to breathe, OSA only disrupts breathing, making it more difficult. This is because the pathway that you use to breathe gets blocked because of how the muscles on the back of your neck relax. This causes the amount of oxygen that you are able to inhale to decrease, disrupting your sleep. In more serious cases, as many as 30 disruptions a night have been recorded. The most common cause of OSA is excess weight and obesity.

Mixed / complex sleep apnea

Complex sleep apnea comprises 15% of patients, making it the second most common type after OSA. This type of sleep apnea is when patients have both OSA and CSA at the same. However, the symptoms and results vary from patient to patient.

How does sleep apnea make you gain weight?

As previously stated, sleep apnea is one factor in weight gain for patients who are afflicted by this disorder. This is done in a number of different ways relating to both your body and your behavior. Below is a detailed description of each of the reasons that this disorder makes you gain weight:

Hormonal changes

One of the obvious side effects of sleep apnea is sleep deprivation. This sleep deprivation then, in turn, results in a hormonal imbalance in your body – which can lead to weight gain. Two major hormones need to be taken into consideration when talking about appetite: leptin and ghrelin.

Leptin is the hormone that is responsible for telling your body when it is full and, thus, when to stop eating. Sleep apnea leads to a decrease in leptin. This then affects you because what happens in your body is that signal that tells you it is time to stop eating is now faulty. Therefore, you end up eating much more than you normally would.

In addition to the decrease in leptin, there is also an increase in ghrelin. Ghrelin is another hormone in your body and this one tells you when you should eat. It is what makes you feel hungry. So, an increase in this hormone in your body means that your body would tell itself that it is hungry more often. This leads to you eating more often.

So, with the decrease in leptin and the increase in ghrelin, you will then feel hungry more often and will also eat more than you normally would. The result: weight gain.


Another side effect of sleep apnea is fatigue. When you are not getting enough sleep at night, consequently you will feel much more tired during the day. This fatigue then leads to a shift in your lifestyle, which can result in weight gain. When you are tired, you will only do the essential things that you need to during the day so as to not exert yourself too much. This means that physical activities, namely exercise, are done much less frequently, if even at all. Then, the domino effect comes into play. You do not get enough sleep at night, so you are tired during the day. When you are too tired during the day, you do not exercise. This inactivity ultimately leads to weight gain.

Slower metabolism

Sleep apnea can also affect your metabolism, as well. Your metabolism is the rate at which your body burns calories. As stated above, sleep deprivation causes fatigue, and, unfortunately, a side effect of fatigue is that you become less active. Less activity means that fewer calories are being burned. One thing your body is good at is adapting to situations. So, what does that means here? When your body gets used to a small number of calories being burnt, the rate that you burn them with, or your metabolism, then drops to accommodate that phenomenon. A low metabolism then causes weight gain because you are less able to burn the calories that you consume, and you do this at a slower pace.


Sleep deprivation can also lead to a change in the types of food you want to consume. When you do not have enough energy, your body wants to eat foods that give you a high amount of energy in a short serving. However, many of the foods that fit this description fall into the category of junk food, like energy drinks or foods that are high in sugar. You crave them because they give you a burst of energy, but in addition to the crash that inevitably follows, you also gain weight. In addition to this, sleep deprivation also fuels a lack of impulse control, making it even harder to resist these foods in the first place.

Can being overweight increase my chances of developing sleep apnea?

The simple answer to this question is: yes. While sleep apnea does increase your chances of becoming overweight, the opposite is true as well. This is because of the way that fat is distributed when you gain weight. When you gain weight, fat is distributed to different parts of your body, one part being the neck. The fat here is called pharyngeal fat and it can disrupt the pathway for air when a person is asleep. This is also the reason for snoring, which is also a common symptom of sleep apnea in itself. The noises that people make when they snore are a result of the air trying to move through the tight airway that is created when there is too much pharyngeal fat.

Another way that excess weight can inhibit the flow of air to and from your lungs is through an increase in the distance around your abdomen (your abdominal girth). This increase can result in a decrease in the volume of your lung capacity, which leads to restricted airflow.

Both of these factors can result in obstructive sleep apnea. Furthermore, the risk of developing OSA also increases as a person’s BMI (body mass index) increases. If a person even gains 10% of their own weight (for someone who is 100 pounds 10% would be 10 pounds), this risk becomes 6 times higher.

Can treating sleep apnea cause weight loss?

Studies have shown that after patients successfully treat or manage their sleep apnea, they find losing weight easier than when they were affected by the disorder. One important fact is that, as one study by the University of Erlangen-Nuremberg in Germany shows, is that ghrelin levels in OSA patients were higher than those patients who were not affected by the disorder. Then, after participating in continuous positive airway pressure therapy (CPAP), those levels in the OSA patients lowered. This means that the levels of the hormone that made them feel hungry and eat more lowered.

Sleep Apnea Treatment: Continuous positive airway pressure therapy (CPAP)

Continuous positive airway pressure therapy is the most effective and most used treatment for sleep apnea. This method is used for patients with obstructive sleep apnea. What happens is that the patient uses a machine that increases air pressure in their throat while they sleep. This is to make sure that the pathway for air stays open when the patient breathes in. This treatment is done nightly and the CPAP machine will be used in one of the following ways:

  • A mask covering the nose and mouth area
  • A mask that exclusively covers the nose
  • Prongs that are put in the nose

CPAP, though it treats sleep apnea and should logically cause you to lose weight, has also been known to cause weight gain in some patients. However, this weight gain is not substantial – the average amount of weight gain was only about 12 ounces (0.35 kg).

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