Limiting afternoon naps to 20 minutes, exercising, and avoiding stimulants and certain foods will contribute to a good night sleep, with the best quality sleep derived from 10.00pm to 4.00am when the night is at its darkest.
Penang Hospital consultant chest physician Dr Irfhan Ali Hyder Ali was speaking at a public talk on ‘Sleep and Obstructive Sleep Apnoea’ held at the main campus today, organised by WOU’s School of Humanities & Social Sciences and Human Resources Department. He elaborated that the melatonin spike that helps people sleep better occurs between 10.00pm and 4.00am.
He stated that obstructive sleep apnoea (OSA) and other sleep problems can be detected with an electroencephalogram (EEG) which records brain activity when sleeping.
He shared on the two main types of sleep, the rapid-eye-movement (REM) sleep and non-rapid-eye-movement (NREM) sleep. “REM sleep occurs 90 minutes after sleep, and it is when your eyes start to move a lot and is associated with dreams. People awakened from REM sleep report very vivid and sometimes bizarre dreams, but once they go back to sleep and wake up the next morning, they cannot remember.”
In REM sleep, the brain is very active but all the muscles in the body, except for the heart and lungs, are paralysed to prevent you from ‘acting out’ your dreams, Dr Irfhan added. “You go into very deep sleep, the muscles behind the neck become flaccid and you start snoring. The airways can easily completely collapse and cause sleep apnoea.”
He said people go through 5 stages of sleep, and they are NREM sleep Stages 1 to 4, and REM sleep. “In the first 10 minutes, people can be woken up easily. In the next stage, 10-20 minutes after sleep, you will know when you are awakened, and when the phone rings you become fully alert and can engage in conversation without the other person knowing you were asleep.”
He highlighted that in Stages 3 and 4 (30-45 minutes after sleep), you sleep through noises and movements without any reaction, and if awakened, you will feel groggy for the first few minutes.
Dr Irfhan recommended taking afternoon naps of not more than 20 minutes to feel refreshed and alert, with anything longer making you lazy and lethargic.
He said sleep hygiene must be considered before any diagnosis of OSA. He listed sleep hygiene tips like limiting daytime naps to 20 minutes, avoiding stimulants like caffeine and nicotine close to bedtime, exercising, avoiding heavy meals or rich foods before sleep, and ensuring a pleasant sleep environment.
He highlighted that in OSA, gravity and muscle relaxation during sleep allows the tongue to fall back into the throat area and obstruct air flow. “There will be loud snoring and then very quiet when the tongue completely collapses. The person stops breathing followed by sudden gasps.”
He said sleep apnoea occurs when a person stops breathing for 10 seconds or more and has at least a 4% drop in oxygen in the blood, while the less severe hypopnoea is a decrease in breathing. Factors like male, obese, age, alcohol, race and familial history, can influence the incidence of OSA, he remarked.
Dr Irfhan pointed out that OSA can be diagnosed with a sleep study to measure the apnoea-hypopnoea index (AHI), which shows how many times per hour a person stopped breathing. “An AHI of less than 5 is mild, 5-15 is moderate, 15-30 is severe, and more than 30 is very severe.”
He said people do not stop breathing and die from OSA but that it can lead to complications like hypertension, declaring that stroke is the leading cause of death in OSA patients, while other effects are increased insulin resistance, snoring, depression, and heart attack.
During Q &A, he responded that most OSA episodes occur when a person sleeps supine as then there is more chance for the airways to be blocked.