Why You Still Feel So Tired Even After A Full Night's Sleep

You went to bed at a normal time, you didn’t look at your phone before bed, you followed all the golden rules to get a good night’s sleepand you got the full eight hours undisturbed... yet after all that, you wake up drained.

If this sounds familiar, you’re not alone. In fact, according to data from YouGov, three in five women (61%) say they feel tired when they wake up, even when they get a lot of sleep, while around half (49%) of men say the same.

But why does this happen? And what can we do about it?

Why do we wake up tired, even after a full night’s sleep?

Waking up exhausted after what feels like a ‘full’ night’s sleep is more common than people realise, and according to TRT UK, hormone specialists based in the UK, the problem usually isn’t the number of hours you’ve been in bed.

Rather, it’s the quality and structure of your sleep.

“Sleep happens in cycles, moving between light sleep, deep sleep and REM sleep,” explain TRT UK’s hormone health experts. “Deep sleep is when physical restoration happens, while REM sleep is important for mood regulation, memory and mental focus.

“If these stages are interrupted by alcohol, stress, late-night scrolling, blood sugar triggers or even small breathing disturbances, you can technically sleep for seven or eight hours but still wake up feeling groggy.”

Another ‘major factor’ is cortisol, the body’s natural ‘wake-up hormone’. Cortisol should rise slowly in the early morning to help you feel alert, but if your stress levels are increased, your cortisol patterns can be dysregulated, leaving you feeling unrefreshed rather than awake.

The experts add: “Hormones that support sleep and wakefulness, like cortisol and melatonin, work in a delicate rhythm.

“When that rhythm is disrupted by poor light exposure in the day, different bedtimes, or persistent stress, it can lead to that frustrating ‘I slept but I’m still tired’ feeling.”

This can lead to the ‘false rest’ effect

What many people experience is fragmented sleep without awareness. You may not consciously wake up, but micro-arousals (brief interruptions in brain activity) can, over time, pull you out of deeper restorative stages.

Modern life fuels this in many ways:

• Evening scrolling keeps the brain stimulated,
• Background anxiety keeps cortisol elevated,
• Irregular schedules confuse the body clock,
• Artificial light reduces melatonin efficiency,
• Alcohol sedates you, but reduces deep sleep quality.

The result? You log the hours, but miss the repair.

As deep sleep is where tissue repair, immune strengthening and physical recovery happens, while REM supports emotional processing and cognitive focus, disrupted cycles can leave you feeling physically heavy and mentally dull the next day.

Can you fix the ‘false rest’ effect?

Methods to combat this are often more about your daily rhythm, rather than just ‘sleeping more’.

TRT UK’s experts advise focusing on consistency, in other words going to bed and waking up at nearly the same time each day; getting natural light within 30 minutes of waking up; and limiting alcohol and heavy meals near bedtime. 

The experts also warn that keeping control of evening stress is a key step to better sleep. This is because high cortisol late at night can ruin the chance of falling into restorative sleep.

They advise: “Slowly and gently create a wind-down routine reduce screen time, low lighting, a warm shower and simple breathing exercises will help signal to the nervous system that it’s safe to switch off.”

Finally, if fatigue continues even with good sleep patterns, it’s worth looking into underlying factors such as thyroid health, iron levels or a wider hormone imbalance – speaking to your GP about this is key.