The Complex Relationship Between Sleep Apnea and Weight Gain

Written by Ahmed Zayed Helmy, MD, on July 06, 2021

A wide spectrum of factors makes an impact on our weight. Overall health is crucial here. Certain health problems may seem entirely unrelated to body weight, but may prevent weight loss and even contribute to weight gain. One of those problems is sleep apnea. The relationship between sleep apnea and weight is complex, to say the least. In this post, we are going to explore it, though. Scroll down to learn more about sleep apnea and how it affects your weight loss efforts.

What is Sleep Apnea?

Sleep apnea is a serious sleep disorder indicated by abnormal breathing during sleep. In this condition, breathing repeatedly stops and starts. The temporary lapses in breathing result in low-quality sleep and affect the body’s supply of oxygen. Potentially serious health consequences may occur due to sleep apnea.

Not all cases of sleep apnea are the same. Different types of this sleep disorder include:

Obstructive sleep apnea (OSA) – the most common and well-known type of sleep apnea; occurs when throat muscles relax and the airway at the back of the throat becomes physically blocked
Central sleep apnea (CSA) – develops when the brain fails to send proper signals to the muscles that control breathing
Complex sleep apnea syndrome – also known as treatment-emergent central sleep apnea; happens when a person has both OSA and central sleep apnea

The exact prevalence of sleep apnea is unknown. While numbers show the estimated prevalence of OSA in U.S. adults is 2-9%, we need to keep in mind that many cases are undiagnosed (1). Many people do not seek help for this sleep problem. At the same time, different studies used different criteria for diagnosing the condition which also contributed to unclear prevalence.

What Causes Sleep Apnea?

The cause of sleep apnea depends on the type of the condition. For instance, obstructive sleep apnea occurs when muscles in the back of the throat relax. These particular muscles support the soft palate, the uvula (a piece of tissue hanging from the soft palate), tonsils, sidewalls of the throat, and tongue. When these muscles are relaxed, airways narrow or close as you try to inhale. As a result, you can’t get enough air which can reduce the oxygen levels in the brain. The brain notices you can’t breathe and rouses you from sleep so the airways can open. This happens so quickly and briefly that you don’t even remember it.

Everyone can develop sleep apnea, but some people are at a higher risk than others. common risk factors include:

Smoking
Excess weight
Nasal congestion
Thicker neck circumference
Being male
Family history of sleep apnea
Being older
Narrowed airway
Use of sedatives, tranquilizers, or alcohol
Medical conditions such as type 2 diabetes, high blood pressure, congestive heart failure, Parkinson’s disease, etc.

Symptoms of Sleep Apnea

The most common signs and symptoms of sleep apnea include (2):

Loud snoring that may include gasping for air, snorting, or choking
Irritability
Waking up with a dry mouth
Difficulty staying asleep
Morning headache
Daytime sleepiness
Difficulty paying attention while awake

Sleep Apnea and Weight

Sleep apnea and weight have a complex relationship which we are going to discuss further in this post.

Excess weight increases the risk of sleep apnea

As seen above, multiple factors increase the likelihood of developing sleep apnea and excess weight is one of them. In fact, scientific evidence confirms it. Studies show obesity, especially central adiposity, are powerful risk factors for sleep apnea as they increase pharyngeal collapsibility through mechanical effects on soft tissues and lung volume. Excess weight can contribute to sleep apnea through other mechanisms such as adipokines (central nervous system-acting signaling proteins) that could affect airway neuromuscular control (3).

The prevalence of OSA in obese and severely obese men and women is almost twice that of normal-weight adults. Patients with mild OSA who gain 10% of their baseline weight are at a sixfold-increased risk of progression of sleep apnea. An equivalent weight loss, though, can result in over 20% improvement in the severity of OSA (4). It’s useful to mention that the higher prevalence of OSA isn’t limited to adults only, it’s present in children as well. Obese children have a 46% prevalence of OSA than their normal-weight counterparts (5).

Excess weight may worsen sleep apnea due to fat deposition at specific sites. For example, fat deposition in the tissues surrounding the upper airway (called pharyngeal fat) may result in a smaller lumen and the above-mentioned higher collapsibility. Pharyngeal fat can block the upper airway during sleep when the airway is relaxed. This explains why snoring is the most common symptom of sleep apnea – air is squeezed through a restricted airway and creates a loud noise.

Additionally, fat deposits around the thorax (chest) decrease chest compliance and functional residual capacity thereby increasing demand for oxygen. In other words, excess fat in this area compresses the chest wall and reduces lung volume thus decreasing lung capacity and diminishing airflow (6).

Sleep apnea can contribute to weight gain

The impact of excess weight on the development of sleep apnea is well-established, but the relationship between them doesn’t stop there. You see, the link between sleep apnea and weight is a two-way street. Just like excess weight can contribute to the development of sleep apnea, vice versa applies. Sleep apnea could contribute to weight gain or complicate your weight loss. If you’re trying to slim down and nothing seems to work, maybe sleep apnea is the obstacle you need to overcome.

A study from the Thorax explored the impact of OSA on weight gain. According to the study, the retrospective data indicate those with recently diagnosed OSA are more likely to have had recent weight gain. These results have been used to support the notion that OSA causes weight gain. But there was still room to assume the weight gain could have been behind OSA. However, a link between OSA and elevated leptin levels, which decrease with continuous positive airway pressure (CPAP) therapy, suggest that an impact of sleep apnea on weight gain could be mediated by leptin resistance. Leptin is a hormone that decreases appetite and helps control weight. High leptin levels increase appetite and contribute to overeating and weight gain (7). In a nutshell, OSA could increase leptin levels and thereby lead to weight gain. This may also jeopardize your weight loss e.g. if you still find yourself eating too much despite making effort to exercise.

The above-mentioned study reveals the extent of complexity of this relationship. While some research reported that initiation of CPAP therapy induced mild weight loss, other studies showed the opposite effects. One study even found that CPAP led to weight gain and the reason could be increased appetite. Lowering of leptin levels won’t change much about weight unless leptin resistance is addressed (8).

The mechanisms through which sleep apnea could lead to weight gain are not entirely clear. A lot more research on this subject is necessary to understand the process and thereby make it easier for people to slim down and maintain weight in a healthy range, even if they have OSA.

Evidence shows OSA could lead to weight gain due to decreased activity levels and increased appetite, especially for refined carbohydrates. Whether obstructive sleep apnea predisposes to preferential accumulation of visceral fat remains to be seen. The CPAP therapy of obstructive sleep apnea appears to decrease the amount of visceral fat even in patients without significant weight loss and it may also lower leptin levels (9).

Additionally, OSA is associated with an elevated systemic inflammatory state. Why is this important? You see, systemic inflammation is linked with a short duration of sleep (10). Evidence confirms that short sleep duration is independently associated with weight gain, especially in younger age groups (11). What we can conclude here is that duration of sleep is an important regulator of body weight and metabolic and endocrine function.

Not only does OSA contribute to weight gain through impaired leptin levels and decreased physical activity, but it is also involved in inflammation and the consequences associated with it. These consequences include short sleep duration which can also lead to excess weight.

Now we see why sleep apnea may complicate weight maintenance or a person’s weight loss efforts. This suggests that treatment of sleep apnea could help you slim down and vice versa.

Why does sleep apnea reduce physical activity levels, you wonder?

To get an answer to this question you need to recall the symptoms of this sleep disorder. Remember, daytime sleepiness is a common symptom of sleep apnea. Since your sleep during the night is interrupted, you wake up feeling tired. As a result, you are extremely sleepy during the day. That happens because your energy levels are low. Depleted energy prevents you from increasing activity levels and exercising. Since both healthy weight management and weight loss require regular workouts, it’s easy to see why failing to become more active can undermine these efforts.

Treating Sleep Apnea

Sleep apnea is a condition that you should not ignore. When left unmanaged, this sleep disorder can lead to a number of complications such as:

Daytime fatigue
High blood pressure
Cardiovascular problems
Type 2 diabetes
Metabolic syndrome
Liver problems
Complications with surgery and medications

The consequences of sleep apnea extend beyond body weight. To manage this problem you need to be proactive, see the doctor, and follow their instructions. The most important treatment measure for the management of OSA is weight loss. Studies confirm that weight loss can aid the management of sleep apnea even in people with type 2 diabetes. As you’re well-aware, it can be difficult for persons with diabetes to slim down. While weight loss contributed to the long-term management of OSA scientists explain a comprehensive treatment approach is necessary, beyond weight reduction (12, 13).

How Does Weight Loss Help with Sleep Apnea?

After weight loss, the nasopharyngeal collapsibility and resistance decrease implying that the caliber of the upper airway increases (14). As you lose weight, fat deposits in soft tissue and chest area also decrease thus making it easier for you to breathe during sleep. It’s also useful to mention the duration of sleep increases which translates to increased energy levels and greater motivation to exercise or eat healthily.

Besides weight loss, CPAP breathing devices also pose as an important treatment method for sleep apnea (15). The role of CPAP devices is also significant for weight loss. Overweight or obese people with OSA can lose more weight if they combine a calorie-restricted diet with CPAP machine use (16).

Basically, weight loss and sleep apnea treatment can go hand in hand. Losing weight is crucial for persons with OSA. On the other hand, managing OSA is important for persons who want to slim down.

If you have OSA, the doctor recommends the most suitable treatment approach based on the severity of your condition. Besides weight reduction and CPAP, your treatment may also include:

Bilevel positive airway pressure (BPAP) devices provide more pressure when you inhale and less when you exhale
Oral appliances that open your throat by bringing the jaw forward
Treatment for associated medical problems including heart or neuromuscular disorders
Supplemental oxygen
Adaptive servo-ventilation (ASV), an airflow device that learns a patient’s normal breathing pattern and stores the information in a built-in computer. Once you fall asleep, the machine uses pressure to normalize breathing
Surgical procedures such as tissue removal, tissue shrinkage, jaw repositioning, soft palate implants, nerve stimulation, and tracheostomy (creating a new air passageway)

Sleep Apnea Management Tips

If you are overweight or obese and have OSA, managing this condition could help you slim down through the mechanisms we described above. So, in addition to doctor-recommended treatment, you may want to modify your lifestyle. These tips could help you out:

Quit smoking
Limit alcohol consumption or avoid it entirely
Avoid caffeine and heavy meals close to bedtime
Sleep on your side
Establish a sleep schedule where you’ll get seven to nine hours of sleep. Keep in mind the sleep schedule also involves having bedtime at the same time every night and waking up at the same time every morning
Avoid sedatives and sleeping pills
Avoid foods high in fat and sugar
Decrease consumption of fried, junk, and fast food

Conclusion

Both sleep apnea and overweight/obesity are common problems and they tend to overlap. An overweight person is more likely to develop sleep apnea. On the flip side, a person with sleep apnea is prone to weight gain. The relationship between the two problems is a complex two-way street that requires further studies and thorough research. Healthy lifestyle measures indicated by a regular sleep schedule, a well-balanced diet, and regular exercise are necessary for both management of sleep apnea and weight loss. If you’re experiencing symptoms of sleep apnea, you may want to consult your doctor. Managing this condition could help you slim down.