For most people, 7-9 hours of sleep each night is considered ideal. But quality sleep is not just measured by the amount of sleep you get; it also considers how well-rested you feel when you wake up. Interestingly, when we’re asleep, our body goes through different stages of the sleep cycle, categorised into two main stages: non-rapid eye movement (non-REM) sleep and rapid eye movement sleep (REM).
In an interaction with the OnlyMyHealth team, Dr Sibasish Dey, Head of Medical Affairs, South Asia, ResMed, explains that deep sleep occurs in the third stage of NREM sleep, characterised by slow brain waves, a lowered heart rate, and minimal muscle contraction. During this stage, the body undergoes physical restoration by repairing tissues, building muscle, and strengthening the immune system. But apart from that, it plays a crucial role in enhancing overall sleep quality. Let's find out how.
Also Read: How Maintaining A Sleep Schedule Boosts Your Heart Health: Ways To Create One
What Is Deep Sleep?
Dr Dey describes deep sleep as a crucial phase in the sleep cycle. Also referred to as slow-wave sleep, it typically occurs in longer stretches during the first half of the night, he adds.
According to the Sleep Foundation, electrical activity in the brain during deep sleep appears in long, slow waves called delta waves, which have a frequency of 0.5-2 Hz. These must make up at least six seconds of a 30-second window for that period to be considered deep sleep, the healthy body shares. Once that happens, a person falls into deep sleep within an hour of falling asleep.
How Much Deep Sleep Is Considered Ideal
An adequate amount of deep sleep is essential for people to feel fully restored and rejuvenated when they wake up. However, the ideal amount of deep sleep can only be measured depending on a person’s overall amount of sleep.
Dr Dey says, “The ideal amount of deep sleep varies by age and individual needs. Generally, adults require about 1.5 to 2 hours of deep sleep each night, which constitutes approximately 15-20% of their total sleep duration. The proportion of deep sleep tends to decrease with age, with infants and young children typically experiencing more deep sleep compared to adults, supporting their rapid growth and development. Various factors, such as stress, sleep disorders, and lifestyle choices, can impact the quality and quantity of deep sleep.”
It is also important to note that insufficient deep sleep can lead to impaired cognitive abilities, mood disturbances, and an increased risk of chronic conditions such as cardiovascular disease and diabetes, according to Dr Dey.
What Happens When You Do Not Get Enough Deep Sleep?
The first thing that you might notice is extreme fatigue and tiredness. This can be accompanied by other symptoms, including:
- A lack of rejuvenation
- Decreased attentiveness
- Difficulties in acquiring new information and creating memories
- Desires for high-calorie foods
Dr Dey explains, "The process of forming memories involves deep sleep, and after a night without enough of it, it may be difficult to recall those memories. Getting too little deep sleep can weaken immunity against infection and lower the strength of the immune response. Particularly, skipping slow-wave sleep may increase insulin resistance, which in turn accelerates the onset of type 2 diabetes and heart disease."
Additionally, a study published in the Pflügers Archiv - European Journal of Physiology also suggests that during sleep, especially deep sleep, our bodies ramp up production of immune cells and chemicals that help us fight off germs. This is why inadequate deep sleep may make people more susceptible to illness.
Also Read: Do You Struggle To Sleep At Night? Try These Tips To Improve Your Quality of Sleep
Tips To Improve Quality Sleep
Here are a few expert-recommended strategies to get more deep sleep and improve overall sleep quality:
Adhere to a consistent sleeping schedule: Regardless of the weekends, fall asleep and wake up at the same time each day.
Develop a favourable sleep environment: Make certain that the bedroom is dark, quiet, and cold. White noise machines, earplugs, or curtains can help reduce disturbances.
Restrict contact with electronic devices: The blue light that these electronics emit may block the synthesis of melatonin, a hormone that controls sleep. According to the ResMed Sleep Survey 2024, 25% of Indian respondents stated that screens and other electronics kept them up at night. It is therefore crucial to try to put electronics away at least an hour before bed.
Implement relaxation methods: Set aside time for relaxation before going to bed to help the body and mind get ready for sound sleep. This can involve practices like progressive muscle relaxation, deep breathing, meditation, or light stretching.
Recognise sleep-related disorders: Inadequate sleep could result from a sleep disorder or illness that prevents an individual from consistently getting enough sleep. One such sleep disorder that has been linked to excessive daytime sleepiness (EDS) is obstructive sleep apnoea.
Conclusion
Deep sleep deprivation can cause several health complications and affect overall sleep quality. It is important to recognise the underlying causes or factors that may be contributing to poor sleep health. This should be followed by necessary measures and sleep hygiene practices that have a positive influence on sleep. Consult with your doctor or a sleep specialist to determine an effective plan of action, especially if you’re struggling with sleep issues.
[Disclaimer: This article contains information provided by an expert and is for informational purposes only. Hence, we advise you to consult your own professional if you are dealing with any health issues to avoid complications.]