In today’s fast-paced world, many people try to hack their sleep, often asking whether 4-5 hours of deep, uninterrupted sleep is better than a full 7-8 hours that’s frequently disturbed. While it may seem like quality trumps quantity, sleep science tells a more nuanced story. According to Dr Joy Desai, Director of Neurology, Jaslok Hospital & Research Centre, Mumbai, both duration and quality matter, but neither can truly replace the other.
What Constitutes Restorative Sleep?
Sleep quality isn’t just about how long you stay asleep. Rather, it’s about how restorative that sleep is. High-quality sleep means progressing through all the necessary sleep stages (light sleep, deep sleep (slow-wave), and REM sleep) in a natural cycle, without frequent disturbances.
Also Read: Ever Wondered Why Old People Wake Up Early? Expert Explains The Science Behind It
According to Dr Desai, sleep is more than just a period of rest; it is a vital biological necessity that fuels cellular, metabolic, and emotional well-being. While modern science has long established sleep’s role in healing, recent discoveries, such as the glymphatic system, the brain’s waste clearance mechanism, have deepened our understanding of its restorative powers.
So, what exactly qualifies as restorative sleep? As per Dr Desai, it includes:
Sleep Duration: Adults need 7–8 hours of sleep daily; teenagers may need up to 10 hours for proper development.
Sleep Timing: Sleep is most restorative when aligned with the circadian rhythm—ideally sleeping four hours after sunset and waking with the sun. In Mumbai, this translates to 10:30–11 pm to 6:30–7 am.
Sleep Disorders: Restorative sleep requires uninterrupted rest, free from conditions like sleep apnoea, restless legs syndrome, or insomnia.
Consistency: Regular sleep and wake times—even on weekends—enhance sleep quality by supporting the body’s internal clock.
4-5 Hours Of Quality Sleep Vs. 7-8 Hours Of Interrupted Sleep: Which Is Better?
While quality sleep is important, duration is equally crucial. Adults generally need 7–8 hours of sleep per night to allow the body and brain to recover, process memories, regulate hormones, and support metabolism. So, what if you’re getting only 4–5 hours of uninterrupted sleep?
According to Dr Desai, this is not enough, even if the sleep feels deep or uninterrupted. "Across the adult lifespan, a human being needs 7-8 hours of sleep apart from teenagers, who may require ten hours,” he clarifies.
On the other hand, 7–8 hours of sleep with occasional disturbances may still allow for enough complete cycles, especially if you can return to sleep relatively quickly, he adds.
However, there has been research which prioritises sleep quality over sleep quantity. A 2021 study published in the journal Children highlighted that sleep quality may be more important than sleep quantity in assessing overall restfulness and well-being. It found that feeling refreshed, staying alert during the day, and achieving deep sleep are key markers of good-quality sleep. While earlier research focused on sleep duration, recent findings suggest that quality plays a bigger role in health. However, more studies are needed, especially in children and adolescents, to fully understand the long-term impact of sleep patterns.
Verdict as per Dr Desai: While neither option is ideal, 7–8 hours with mild interruptions is generally better than consistently short, uninterrupted sleep. But the goal should always be to improve both duration and quality, not settle for one at the cost of the other.
Also Read: Always Wake Up Tired? Here's What You Can Do
Common Causes Of Interrupted Sleep And How To Fix Them
Interrupted sleep can be triggered by a variety of factors, including:
Sleep Apnoea
Sleep apnoea is a condition where breathing repeatedly stops during sleep. Some of the common treatments include medical evaluation, use of a Continuous Positive Airway Pressure (CPAP) machine, and weight management.
Restless Legs Syndrome (RLS)
It is the uncontrollable urge to move the legs, especially at night. Depending on the cause, RLS can be treated with iron supplementation if deficient and dopamine-modulating medications.
Anxiety and Stress
Anxiety is characterised by racing thoughts or heightened cortisol levels that tend to disrupt sleep onset and maintenance. Mindfulness practices, Cognitive Behavioural Therapy (CBT), and limiting screen time before bed can be some of the ways to manage the condition.
Noise, Light, and Temperature
Environmental disturbances can trigger awakenings, which can be treated with the use of blackout curtains, earplugs, or white noise machines. Additionally, you can maintain a cool room temperature.
Caffeine and Alcohol
Caffeine and alcohol can both impair deep sleep and increase nighttime awakenings. Therefore, avoiding caffeine after 2 pm and alcohol close to bedtime can be helpful.
Health Risks Of Poor Sleep Quality And Quantity
Chronic lack of restful sleep can lead to a wide range of health problems, including:
- Hypertension: Sleep regulates blood pressure; poor sleep raises it.
- Diabetes and weight gain: Sleep affects glucose metabolism and hunger hormones.
- Mood disorders: Increased risk of anxiety, depression, and mood swings.
- Weakened immunity: Sleep helps the body fight infections and heal.
- Cognitive decline: Poor sleep impairs memory, concentration, and decision-making.
- Increased risk of cancer: Studies link sleep disruption with higher risks of breast and lung cancer.
Conclusion
Sleep quality and quantity both are vital. While 4–5 hours of deep sleep may seem efficient, it isn’t enough to meet the body’s full restorative needs. Similarly, long hours in bed interrupted by frequent awakenings won’t leave you refreshed. So, aim for 7–8 hours of uninterrupted sleep but also maintain consistency every night. Therefore, prioritise both quality and consistency, as your health depends on it.