A 55-year-old business executive, doing well at his work and personal life noticed that he was putting on excess weight. He also noticed that he was getting tired and forgetful, which he attributed to his ageing. Fortunately he was not suffering from any major illness.

One day, while he was driving, he rammed into the road divider. He does not remember exactly what happened, but he thought he might have fallen asleep, not the first time that this had happened while driving. When he opened his eyes, he was in a hospital thanking god for saving him from a major disaster.  We later diagnosed him to have obstructive sleep apnoea (OSA).

Similarly, a 45-year-old man with body weight of more than 90 kg was admitted to Narayana clinic with high blood pressure. He was being treated for it for more than a year with three different classes of medication. His spouse complained that he used to snore loudly and sometimes stops breathing transiently while sleeping. He too was diagnosed to have OSA.

Sleep disorders leading to excessive day-time sleepiness can be disastrous if left unaddressed. More than 40% of adults have sleep-related complaints. Ideally, an adult should sleep for six-and-a-half hours to eight hours. Not only the duration of sleep, but also its quality and pattern are important to maintain good mental and physical health.

Sleep disordered breathing, predominant in OSA, is one among the various disorders of sleep that affect almost all systems of the body.

When we sleep, muscles gradually relax, which is good. The deeper the sleep, the greater the loss of muscle tone. The upper airway is a muscular tube, held open by muscle contraction. So when we sleep and our muscles relax, the airway is constricted. Initially, this narrowed airway leads to snoring, but as the obstruction to breathing gets more pronounced, there is a drop in airflow (hypopnoea — less breathing).

When the obstruction is complete or near-complete, there is no breathing at all — this is an apnoea. There are also other causes of apnoea, but obstructive apnoeas are the most common. As these apnoeas occur in sleep, they are called Obstructive Sleep Apnoeas or OSA.

As airflow reduces or ceases, oxygen level in the blood falls. This drop in oxygen level or the airway obstruction can wake the patient up, and these arousals can occur throughout the night, often every minute or even more often. With arousal, the muscle tone returns to normal and the patient begins to breathe normally again, but the cycle may repeat after a short time. 

Obstructive sleep apnoea can occur at any age, including in children. However, it is more common in people over 50 years of age. Men are more prone to OSA as compared to women. Also, obese individuals are more likely to have OSA, although about 10% of people with OSA are of normal weight. About 2.4% to 5% of male and 1% to 2% of female population is known to suffer from OSA in India according to the latest statistics.

Snoring menace
Even though snoring is considered as a sign of sound sleep widely, ironically, snoring indicates that the airways are getting blocked during sleep. Snoring and stoppage of breathing/ choking or arousals are reported more commonly by the spouse than the patient. Other symptoms include restlessness, tossing in bed and frequent awakenings for toilet visits.

Patients usually experience unrefreshing sleep, wish they could sleep longer in the morning, wake up with morning headaches, feel tired during the day. They feel excessively sleepy while engaged in monotonous activities, often have poor memory, exhibit mood swings and have difficulty in concentration.

The gold standard test for diagnosis is polysomnography/ sleep study, where your sleep is assessed for its stage, quality and for arousals. It includes checking abnormalities in breathing, oxygen concentration in blood, cardiac functions and any movements during sleep. The test is done in a sleep lab.

To cure OSA, maintain sleep hygiene — which means use the bedroom only for sleep and sex, and not for working, playing video games etc. Get to bed early, ensure that the lights are off, and get at least six-and-a-half hours of sleep. Avoid caffeinated drinks like tea or coffee after 7 pm and eat a light, easily digestible dinner.

(The writers are with the Department of Pulmonology, Narayana Health City, Bengaluru)