Why is my sleep light and unrefreshing?

Light, unrefreshing sleep. 

Have you ever felt as if you’re skimming the surface of sleep for much of the night? You dip in and out, perhaps catching the odd dream, but never feel as if you sink into the deeper, more oblivion-like parts of sleep. The smallest noises wake you, and sometimes you’re not even sure whether what you experienced was sleep or wake. Instead, it feels like an unpleasant limbo.

Around 40% of Australians report dissatisfaction with their sleep, and around 10 to 15% experience chronic insomnia that significantly interferes with daily life. Feeling that sleep is too light or fragmented is one of the most common reasons people seek help or turn to solutions. There are two things worth understanding about this experience that can genuinely help.

What do we do about this?

People respond to light and fragmented sleep in different ways. Some simply get on with life, carrying the belief, “I’m a light sleeper, that’s the card I’ve been dealt.” Others actively try to fix it. They seek out advice, products, and devices that promise deeper, more solid sleep. Along the way, many people encounter misinformation about the causes and consequences of light sleep, and absorb the idea that good sleep should feel like being knocked out cold.

Therapists may encourage stress reduction, which can help for some people. Others begin tracking their sleep closely, matching nightly “sleep quality” scores to the events of the day before. All the while, two important and often overlooked factors remain in the background.

So what are they?

First, a reality check.

The first is a reality check that many people find both confronting and relieving. Experiencing light sleep, from which you are easily woken, is normal.

“The best sleep I ever had,” someone once told me, “was when I went under a general anaesthetic for surgery.” A general anaesthetic is not sleep. It is pharmacological sedation, and it delivers none of the benefits of natural sleep. It feels like total oblivion, but it achieves zero restoration.

Unfortunately, we have absorbed the idea that good sleep should resemble impenetrable unconsciousness. It is worth pausing to consider how poorly that expectation fits with human survival. If our ancestors slept like the dead, we would not be here.

Here are a few points worth knowing about light sleep and awakenings overnight:

• We spend most of the night in lighter stages of sleep, particularly in the second half of the night, often in the early morning hours.

• Deep sleep makes up around 20% of total sleep time in adults, and this proportion declines with age.

• Light sleep plays an important role in memory formation and consolidation.

• Our arousal threshold during light sleep is lower, meaning it is easier to be woken. While inconvenient, this has likely been advantageous for survival.

• All stages of sleep are peppered with brief arousals. Most adults fully wake several times each night, although we usually forget these awakenings by morning.

This picture is a 'hypnogram.' It depicts a night of sleep based on polysomnography (electrodes all over the scalp and other sensors on the body). As you can see, most of the night is spent in light stages of sleep - the light and dark green. There are also plenty of wakes and arousals. The individual in this study has no sleep complaint or disorder. Source: Riemann, D., Benz, F., Dressle, R. J., Espie, C. A., Johann, A. F., Blanken, T. F., ... & Van Someren, E. J. (2022). Insomnia disorder: State of the science and challenges for the future. Journal of sleep research, 31(4), e13604.

Taken together, these features suggest that light sleep is not a flaw in the system. It is a core part of how sleep works. It is probably in need of better public relations.

If you find yourself thinking, “This may all be true, but my sleep used to feel much more solid,” it is worth considering the role of age. Just as joints stiffen and skin loses elasticity, sleep becomes lighter and more fragmented over time. Unlike joints or skin, however, we do not yet have a way to replace ageing sleep.

Before concluding that the message here is simply to accept what cannot be controlled, there is one evidence-based way that some people can improve sleep depth and continuity.

Improving sleep depth and continuity.

Sleep is regulated by two interacting processes.

The first is the circadian rhythm, often referred to as the body clock. This system governs daily rhythms in alertness, melatonin and cortisol secretion, and body temperature. When the circadian rhythm is well aligned, the brain has a strong signal that it is night-time across the usual sleep window. Because light exposure is the primary cue that sets this rhythm, much sleep advice focuses on managing light through the eyes.

The second, often lesser-known process is sleep homeostasis, or sleep pressure. From the moment we wake, the brain’s drive for sleep begins to build. As sleep pressure increases, falling asleep becomes easier and sleep tends to be deeper and more continuous. Even when we try to stay awake, sleep pressure eventually overwhelms our ability to do so.

For most adults, this means being awake for around 16 to 17 hours before bed.

The key to consolidated sleep is finding your individual sweet spot. How much time does your body need to be awake in order to generate enough sleep pressure for one solid block of sleep overnight? If you tend to need around seven hours of sleep, this often means a wake-up time of 7am and a bedtime closer to 11pm or midnight.

Many of us spend too long in bed

There are understandable reasons for this. We are tired from the day and want some time out. Sleep has felt fragile lately, so we try to give ourselves more opportunity. Our partner goes to bed early, so we join them.

The problem is that many people go to bed before their sleep pressure is high enough. This can show up as difficulty falling asleep, waking frequently during the night, waking earlier than intended, or a combination of all three.

A common analogy in behavioural sleep medicine involves pizza dough. Imagine you need seven hours of sleep. If you spend eight or nine hours in bed, you are trying to stretch a fixed amount of dough too far. The result is thin patches or holes. 

In experimental studies, when people are given a slightly restricted sleep opportunity, sleep quality often improves rapidly.

This principle underpins one of the core components of evidence-based treatment for insomnia. Clinicians work collaboratively to assess whether there is a mismatch between sleep need and time in bed, and then test what happens when sleep opportunity is reduced modestly and deliberately.

If you notice that much of your night feels thin or fragile, it may be worth gently reducing your time in bed by 15 to 30 minutes at a time, avoiding naps, and anchoring a consistent wake-up time.

Regular daytime activity, particularly exercise, is one of the few modifiable factors known to improve sleep quality.

Closing remarks

Light sleep that we are easily woken from is sometimes a fact of life. Chasing better sleep, especially night after night, often reinforces dissatisfaction without improving sleep itself.

It is counterintuitive, but in many cases the path to deeper, more continuous sleep involves being awake for longer, not trying harder to sleep. The evidence for this is remarkably strong.

Of course, there are plenty of other reasons we can feel poorly rested overnight, but these reasons are often overlooked. I will come back to the others in time!