An average human spends about one third of their lifetime in slumber. This is hardly time wasted as this restorative phase allows the body and mind to repair itself, clear toxins and grow. While one may not appear noticeably sleepy during the day, losing even an hour of sleep can affect the ability to think or react quickly. Besides prolonged fatigue, there may also be other hidden dangers such as weight gain.
In this article, we speak to Dr. Paul Mok, Senior Consultant at Farrer Park Hospital, to find out more about Obstructive Sleep Apnea (OSA) and the adverse effect it can have on our health if not treated.
Four stages of sleep and how they affect our body
While it varies from one person to another, it is important for healthy adults to get up to seven hours of uninterrupted sleep every night. Before you find out more what exactly defines uninterrupted rest, let’s understand the normal sleep cycle first.
A sleep cycle consists of four stages. You transit from wakefulness into stage one and two of sleep which are light sleep. From there you go into stage three or deep sleep. Lastly, you enter into stage four, dream or Rapid Eye Movement (REM) sleep. We have more stage three sleep in the first half of the night and more REM sleep in the second half. Deep sleep is restorative sleep, accompanied by slower heartbeat and rise of breathing. Here, your muscles would relax and brain waves progressively slow down.
During REM sleep, your brain becomes active again, showing wave patterns similar to when you are awake. Both Stage Three and REM sleep (deep sleep) are important because neural connections and memory consolidation occur here. You need enough deep sleep to feel refreshed the next morning when you wake up.
Bad sleep disrupts the sleep cycle, in particular, it reduces deep sleep. This can have a negative impact on your physical and mental health. One of the common causes of bad sleep is OSA.
Obstructive sleep apnea: the bringer of bad sleep
As Dr. Mok explains, OSA occurs when your upper airway narrows during sleep. This obstruction happens frequently when the nose is blocked or if the soft tissue at the rear of a sufferer’s throat relaxes, blocking the airway. The airway collapse leads to the signature “rasping sound of a snore” that can be embarrassing to the sufferer, and disturbing to family members one shares a room with.
This collapse can be partial or even complete, where breathing can pause for 10 seconds or more. This results in lower oxygen during sleep (known as oxygen desaturation) and higher carbon dioxide level as the brain centers that regulate breathing are less responsive during sleep.
In response, the sufferer’s heart will pump harder to compensate, becoming stressed. Blood pressure will also rise as blood vessels contract, increasing the risk of cardiovascular disease. Overtime, this undue stress results in irregular and abnormal heart rhythm that can lead to sudden death. Dr. Mok likens this to running on a treadmill every night rather than having a restful sleep that relaxes the heart.
Equally harmful is its effect on sleep quality as a sufferer will often be aroused to a lighter stage of sleep in an effort to restore breathing. This causes daytime sleepiness and poorer mental health that can translate to poorer work quality, social and emotional problems, and even dangers such as higher likelihood of automobile accident especially if the sufferer drives.
If the sufferer shares the bed with a partner, this can also hurt the relationship by disturbing the partner’s sleep and leading to potential daytime quarrels.
How to tell if you have OSA
Dr. Mok points to having a chronic and severe snoring that can be unbearable to a spouse. If you sleep alone, you can use a recorder to identify loud, raspy snoring. Another tell-tale sign is when long hours of sleep do not allay tiredness. You remain fatigued in the day. This can translate to accompanying signs like poorer memory and concentration problem, irritability and morning headaches.
You should also consider risk factors. Being an overweight male with a family history of OSA, or having certain physical attributes like receding chin or a large neck circumference can put you at greater risk of having OSA.
If you suspect even the slightest, Dr. Mok encourages you to visit an ENT specialist who can help to diagnose and treat you. Available treatments include continuous positive airway devices (CPAP), oral appliances and surgery.
Other interesting facts that influence sleep quality
Alcohol can worsen your sleep quality. Whilst alcohol may make an individual drowsy, Dr Mok adds that alcohol-induced sleep is associated with a light sleep and less REM sleep. Alcohol is also a diuretic which makes you want to get up to urinate. This will also interrupt your sleep. The total sleep duration is also reduced. Often, you may get up in the middle of the night and find that you cannot fall back to sleep.
There is also a connection between nutrition and sleep. Good sleep seems to improve nutrition intake while a bad one stirs an unhealthy appetite to eat more and risk weight gain. Dr. Mok gives an advice here too: “You should not eat and sleep immediately. Partially digested food and gastric acid may flow backwards up into the esophagus and larynx, causing heartburn and throat discomfort, among others that can be sharply felt in the morning.”