Why Do Some People Snore and Drool in Their Sleep? The Science Behind It

When the entire house is deep asleep at night, a strange sound often begins coming from one particular room one that can be enough to disturb anyone's sleep. Sometimes it is the loud, engine-like sound of snoring, while at other times, the first thing we notice in the morning is a large patch of saliva on the pillow. At some point in our lives, most of us have either experienced this ourselves or watched a friend, sibling or partner snore or drool in their sleep. At first glance, it may seem like a harmless, funny and even amusing habit. 

From hostel-room jokes to the playful teasing between husbands and wives, snoring and drooling have long been treated as things to laugh about. But when we look deeper into medical science and the way the human body works, these nighttime habits are much more than simple physical occurrences. They can reflect several biological processes taking place inside the body, the relaxation of muscles, the way we breathe and even the impact of our modern lifestyle.

When we fall asleep, the entire body enters a state of deep relaxation. While we are awake, the muscles in our throat, tongue and the roof of the mouth remain active and help keep the airway open, allowing air to move freely towards the lungs. But as we enter deeper stages of sleep, these muscles gradually relax. When the airway becomes narrower because of this relaxation, the pressure and movement of air passing through it can increase. The soft tissues at the back of the throat then begin to vibrate as air moves through the narrowed passage, producing the familiar sound we call snoring. Drooling during sleep has a relatively simple explanation as well. When we are awake, the brain continuously helps regulate swallowing, and we swallow saliva automatically without even thinking about it. But when we sleep on our side or stomach rather than on our back, and our sleep is deep enough for the muscles around the face and jaw to relax completely, the mouth may fall slightly open. When that happens, instead of being swallowed, saliva can flow out of the mouth due to gravity.

If we look at the history and cultural understanding of snoring, it was once associated with deep, peaceful sleep. In villages and earlier generations, there was even a common belief that someone snoring loudly must have worked extremely hard and was enjoying a very restful sleep. In other words, snoring was often seen as a sign that a person was tired and sleeping deeply. Modern medicine, however, has challenged this assumption. Sleep specialists and doctors point out that not every case of snoring is harmless. In some people, persistent and loud snoring can be an early sign of a condition called obstructive sleep apnoea, in which the airway repeatedly becomes blocked during sleep, causing breathing to stop temporarily and oxygen levels in the body to fall.

From an Ayurvedic perspective, an imbalance involving Kapha and obstruction in the respiratory passages have traditionally been associated with problems such as snoring and excessive saliva. In earlier India, people were generally more physically active, walked more, ate simpler meals and often finished dinner around sunset. Modern Indian lifestyles, particularly among young people, are very different. Working late into the night, eating heavy meals after 10 p.m., consuming rich or fatty foods such as paneer, and having dairy products such as curd late at night are often considered factors that may contribute to congestion and excess mucus or saliva. Long hours in front of screens, excessive consumption of junk food, declining physical activity and increasing body weight have also become important factors associated with snoring among today's younger population.

When a person gains weight, fat does not accumulate only around the stomach or thighs. Fat can also build up around the neck and throat, putting additional pressure on the airway. This can make the passage narrower and make breathing more difficult during sleep. At the same time, increasing levels of stress and anxiety have led some people to rely on sleeping pills, alcohol or other substances in an attempt to get better sleep. Alcohol and certain sedative medications can cause the muscles of the throat to relax more than usual, which may make snoring louder and more frequent. If the mouth remains open for longer periods, the chances of drooling also increase. Technology has added another layer to the problem. Spending long periods looking at the blue light of a smartphone while lying in bed can interfere with the body's natural sleep cycle and reduce sleep quality. Poor-quality sleep can also encourage irregular breathing patterns, including breathing through the mouth.

The issue is not limited to physical health. It also has a significant social, psychological and relationship-related side. In married life, one partner's loud snoring can sometimes become a genuine source of conflict. In many cities, the idea of “sleep divorce,” where couples choose to sleep in separate beds or rooms because of sleep-related problems, has become increasingly discussed. A person sleeping next to someone who snores may wake up repeatedly throughout the night and feel irritated, exhausted and mentally drained the following day. At the same time, the person who snores or wakes up to find saliva on their pillow can experience embarrassment and self-consciousness. When someone wakes up while travelling on a bus, train or flight, one of the first things they may do is quickly wipe their mouth to check whether they drooled in their sleep. Students living in hostels and young people travelling with friends may even struggle to sleep comfortably because they worry about being teased the next morning.

From an economic and corporate perspective, poor sleep can have a direct impact on workplace productivity. A young professional who spends the night sleeping poorly because of frequent snoring may struggle with burnout, mental fatigue and lack of concentration the following day. At a larger level, sleep-related productivity losses can also create significant economic costs for companies and economies. This is one reason why some organisations are increasingly paying attention to employee sleep and well-being, with initiatives such as nap rooms and sleep-awareness programmes becoming more common. At the same time, India's sleep-wellness and sleep-technology market is growing rapidly. Products such as anti-snoring pillows, nasal strips, mouthguards and CPAP machines are widely available, while smartwatches and other modern devices can track sleep patterns, snoring frequency and blood-oxygen levels during the night.

Interestingly, occasional drooling during sleep can also simply be a sign that a person is sleeping deeply and has relaxed completely. During certain stages of sleep, including REM sleep, the body becomes highly relaxed while the brain remains active in processing information and experiences from the day. However, if drooling becomes a regular occurrence and a person is constantly forced to breathe through an open mouth, it may point towards issues such as a deviated nasal septum, chronic allergies or sinus problems. Breathing through the mouth can dry out the throat and reduce the natural moisture in the mouth, which may contribute to problems such as bad breath and a greater risk of dental decay.

Great thinkers and scientists have long emphasised the importance of understanding and caring for the human body. The underlying lesson is simple: when our body produces unusual sounds during sleep or repeatedly causes us to wake up with a dry mouth or saliva on the pillow, it may be worth paying attention rather than simply laughing it off. Snoring and drooling can sometimes be harmless, but they can also act as signals that our lifestyle, diet, weight, breathing patterns or sleep quality need closer attention.

Ultimately, snoring and drooling while sleeping are not necessarily something to be embarrassed about or completely ignored. They can be natural bodily responses, but they can also be warning signs of an underlying health problem or an unhealthy lifestyle. Simple changes such as sleeping on your side instead of always sleeping on your back, having a lighter meal at least a few hours before bedtime, maintaining a healthy weight, reducing screen time before sleep, and avoiding alcohol and smoking can help reduce these problems considerably. If the symptoms continue despite these changes, it is better not to dismiss them as a joke or rely blindly on home remedies. Consulting a doctor or sleep specialist is the wiser approach, particularly when snoring is loud and persistent or is accompanied by pauses in breathing, choking or excessive daytime sleepiness. After all, a peaceful night's sleep is not just important for our physical health; it is essential for our overall well-being and quality of life.