I slept 8 hours but woke up tired — a doctor says this bedtime mistake is to blame

Until recently, I was getting eight hours sleep a night (most adults need seven to nine hours) yet every day I was waking up exhausted. Unable to liv with the morning grogginess any longer, I asked an expert for help and after some probing, the answer became clear: stress. More specifically, I wasn’t relaxing properly and shedding as much stress as possible before bed.

As I’ve since learned, stress keeps your nervous system alert, so you can’t shut off. “Even if you spend eight hours in bed, an alert nervous system can keep your sleep from being truly restorative,” explains Dr. Anita Raja, a sleep expert in partnership with Herbalife.

But the good news, according to Dr. Raja, is that there are simple ways to calm your nervous system and turn those eight hours of sleep into genuinely restorative rest. Here’s what she told me…

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Key take-aways: At a glance

• Stress keeps your nervous system alert, which means even if your body is tired, it can’t fully switch off
• This results in fragmented sleep and frequent wake-ups, preventing you from reaching the slow-wave stage of sleep
• When you don’t spend enough time in these restorative sleep stages, your sleep quality suffers and you’re more likely to wake up tired
• Calming the nervous system can help you enjoy better sleep, even when stressed
• Keep to a calming bedtime routine, to maintain healthy circadian rhythms
• Write down stressful thoughts in the evening, followed by possible solutions and positive moments, to redirect your mindset
• Use the ‘cognitive shuffling’ method when you wake up at 3 a.m. with stress

Why stress means you feel exhausted even after 8 hours sleep

“When we experience stress — whether from a looming deadline, a difficult relationship, or financial worries — the body activates its fight-or-flight response, releasing cortisol and adrenaline,” explains Dr. Raja.

You might recognize cortisol as the hormone that gets you up in the morning, so it’s bad news for sleep when it starts flooding through your body before bed.

“These survival hormones are extraordinarily good at keeping us awake and alert,” Dr. Raja says.

With cortisol levels still high, your sleep typically becomes fragmented, meaning you wake up frequently (albeit briefly) during the night. These disruptions prevent your body from moving into the more restorative stages of sleep — deep and REM sleep.

“Without sufficient slow-wave and REM sleep, both body and brain remain under-recovered, leaving you exhausted, mentally foggy, and physically drained the next day,” explains Dr. Raja. And that happens even if you’ve been asleep for eight hours.

With a survey from Herbalife finding 37% of women in the UK “feel stressed often” and research from Resmed noting 39% of us consider stress a sleep disruptor, it seems I’m not the only one dealing with this exhaustion.

3 ways to reduce stress before bed

Stopping stress before bed isn’t about solving the problems that are causing your anxieties — even the best sleep hacks can’t do that.

Instead, it’s about allowing your brain and body to switch away from stressors to focus on achieving high quality sleep so you can get the restoration you need. Here’s what the experts suggest…

1. Follow a bedtime routine

When I asked three doctors how to avoid sleep inertia and low-energy mornings, they all gave the same advice: keep to a bedtime routine.

Routine provides your body with obvious cues that it’s time for sleep, helping to suppress cortisol and increase production of sleep hormone melatonin.

A good nighttime routine incorporates relaxing hobbies, like reading and meditating, alongside environmental signals that sleep is coming, such as dimmer lights and cooler bedrooms.

Dr. Raja explains that this routine gives your nervous system “space to wind down,” facilitating the move from ‘awake’ to ‘asleep.’ And she emphasizes that taking this time is a must.

“Protecting your sleep isn’t indulgent — it’s one of the most powerful ways to support your overall health.”

2. Write it down

As a sleep writer I’m well aware that I need my snooze if I want to be at my best the next day. But when I’m stressed, it can be hard not to see bedtime as wasted time. This means I can’t quite switch my brain off.

The solution recommended by Dr. Carlos Nunez, sleep expert at Resmed, is to explore these stresses head on.

“Write down three things you’re going to do tomorrow to deal with,” says Dr. Nunez. “‘Hey, I’ve got this deadline at work. I’ve got this thing with my in laws,’ whatever it is stressing you out. Write it down.”

Known as the Constructive Worry Method, you complete it before your bedtime routine to get stress out of your head and onto paper.

And Dr. Nunez recommends following up your worries with some positives.

“Take that hour where you’re winding down and remind yourselves of all the positive things that have happened today, all the good things you have going on,” he says.

3. Cognitive shuffling

Cognitive shuffling is a popular technique among the Digitpatrox team and it’s a simple stress-buster to try at home. Just think of a word and try to imagine items that starts with every letter of that word.

So let’s say you pick ‘cognitive’: cheese, chalk, chaffinch, crayon, orange, orangutan, opal… and so on.

Dr. Nunez describes is as a “reset” for your brain and has a tip to take it up a level.

“[I imagine] I’m actually sitting in my workshop,” he says. “So I will sit in my mind, I’ll say, okay, Carlos, see what in my workshop begins with the letter C?”

If he can’t find items in the workshop, he’ll (mentally) move to a different room, like the kitchen, and start again. Working through a location increases the focus, which in turn can help you sleep.

“I’m so focused on finding the third or fourth letter, I’m asleep,” he says. “I don’t know why, because you would think I’m getting stressed trying to find the letters, but it pulls your mind so far away from your daily stress.”

How stress is stealing your sleep quality

You’d probably find it hard to sleep if you were actively in danger, say, if you knew a tiger was outside your room and it had your scent.

Stress of all kinds has a similar effect on your body and brain. There isn’t a tiger lurking but there might be deadlines, financial strains and difficult conversations preying on the same corners of your mind.

“The challenge is that the brain doesn’t distinguish between a physical threat and a psychological one,” explains Dr. Raja, GP and women’s health expert. “So, when you’re lying in bed worrying, your stress-response system can stay active as though you’re in danger.”

Your body doesn’t want you to fall into a deep sleep, just in case that tiger decides to finally pounce, and it has a hormonal response to keep you alert.

“Cortisol levels — which should naturally drop at night — remain elevated, suppressing the production of melatonin and preventing you from reaching the deeper, restorative stages of sleep,” Dr. Raja says.

She describes the experience as being physically exhausted yet mentally unable to switch off; “caught between a tired body and a nervous system that won’t stand down.”

And it’s a problem that reinforces itself. “The brain begins to associate bed with threat — and that’s when short-term stress can lead to fragmented or shallow sleep, leaving you exhausted even if the hours spent in bed seem sufficient,” she explains.