Why Do I Keep Waking Up at 3 am?

We’ve all been there: no matter how early you go to bed, night after night, you find yourself wide awake at 3 am, unsure why. The reason often comes down to your body’s natural rhythms. Throughout the night, we move through different sleep cycles, alternating between lighter and deeper stages, which can affect how easily we wake up.

In this guide, we explore the common causes of night-time awakenings, such as bathroom trips, stress, and diet, before taking a closer look at the four stages of sleep and tips for getting a more restorative night’s rest.

Most people are in their third or fourth sleep cycle around 3 am, which may include lighter stages like N2 or REM. During these stages, your body is more sensitive to external or internal signals, such as a full bladder. This means that if you need the toilet, you’re more likely to wake up during this lighter phase rather than during deeper sleep earlier in the night.

Ageing plays a key role in your sleep cycles; the older you get, the more likely you are to experience sleep disturbances. One of the main reasons sleep cycles change with age is due to shifts in circadian rhythms, also known as the internal clock, which can lead to sleep interruptions.

A 2019 study found that 50% of adults over 55 had difficulty staying asleep and, therefore, experienced a poor night’s rest. This can also make you feel more tired earlier in the day and cause you to wake up earlier in the morning. Older individuals tend to spend more of their sleep in lighter stages rather than deeper phases, making them more susceptible to waking up.

The transition into menopause is another common cause of night-time awakenings. Hot flashes caused by estrogen withdrawal can make it difficult to stay asleep. For advice on reducing your body temperature, explore our tips on staying cool at night.

Similarly, your menstrual cycle brings its own set of hormonal shifts, including fluctuations in estrogen and progesterone. These natural changes can impact your sleep, sometimes causing discomfort and those annoying wake-ups during the night.

Worried about deadlines or financial burdens? If so, stress could be the main reason for your 3 am nightly awakenings. When you’re stressed, your sympathetic nervous system is activated, triggering the ‘fight or flight’ response. This can cause your heart rate to rise, making it harder to stay asleep. No wonder that endless to-do list is keeping you up at night.

Nightmares and bad dreams are another cause of waking up at 3 am, probably among the most unpleasant ones. If you’re struggling with unsettling dreams, explore practical ways to end nightmares and night terrors.

Dipti Tait, an NSDR hypnotherapist and sleep expert, explains what happens when we experience nightmares:

“Your critical mind is switched off. This means that, as we sleep, we believe whatever we see in our dreams. As a result, if your brain perceives you to be in a stressful situation, it says, ‘No, don’t relax.’ Your body will release stress hormones such as adrenaline and cortisol, waking you up.”

Our internal clocks respond to cues in our environment, such as light and noise. If streetlights or early morning sunlight are coming through your blinds, your body may interpret this as a signal to wake up. Additionally, sleeping with the window open can expose you to outdoor noises, such as passing cars or gusts of wind, which can interrupt your rest.

Sharing a bed can be comforting, but it can also affect your sleep quality. Disturbances like snoring, duvet-hogging, or teeth grinding can wake you up without you even realising it. Even a slight movement, such as your partner rolling over, can disrupt your rest if you’re in a lighter sleep stage. For tips on managing night-time noise, check out our guide on sleeping when your partner is snoring.

While food provides us with energy, what we consume can also directly impact our rest. For example, research has found that people who don’t consume enough carbohydrates struggle to maintain a good night’s sleep.

Caffeinated beverages are also well-known for keeping us awake. Although caffeine is a fast-acting stimulant, it has an average half-life of five hours. So, if you have a standard 95-milligram cup of caffeinated coffee, after five hours, you will still have 47.5 milligrams in your system. However, those sensitive to caffeine may feel the side effects for even longer.

Sleep apnea is a disorder in which, when your muscles are relaxed, your airways temporarily close or narrow, preventing you from breathing properly. Your brain detects the lower oxygen levels in your blood and wakes you up to reopen your airway. These awakenings can be very brief, and you might not even remember them. However, in some cases, they could be the culprit behind waking up during the night.

A full night’s sleep might feel like one long, uninterrupted rest, but your body actually goes through several different sleep stages, all without you even noticing.

The four stages of sleep are referred to as N1, N2, N3, and REM. These stages include:

1. N1—lightest sleep: The first stage, N1, is the transition from wakefulness to sleep, lasting only about 1–7 minutes. It’s a very light stage, and you can be easily woken.
2. N2—deeper sleep: During N2, the body relaxes further, and brain activity slows down. Lasting around 10–25 minutes, this phase prepares you for deeper, more restorative sleep.
3. N3—deep sleep: Known as the most restorative part of the sleep cycle, deep sleep is essential for physical recovery and immune function. Waking up in this stage often leaves you feeling groggy and disoriented. This phase lasts approximately 20–40 minutes and is the hardest to wake up from.
4. REM—dream sleep: REM sleep usually begins about 90 minutes into the sleep cycle and is marked by intense brain activity and vivid dreams. Early REM stages last only a few minutes, but they can extend up to an hour as the night progresses. REM is crucial for cognitive function, memory consolidation, and mood regulation.

In a typical 8–10 hours of sleep, most people will go through these stages 4–6 times, depending on how quickly they fall asleep and how deeply they sleep.