Why you're still tired after eight hours of sleep

It can be frustrating to feel like you’re doing everything right when it comes to sleep, only for your energy to wane from the moment you open your eyes. There is a range of reasons why you might be waking up exhausted and plenty of ways you can wake up on the right side of the bed and increase your energy levels.

According to Dr Preeya Alexander, GP and family health expert known as The Wholesome Doctor, there isn’t a ‘one-size-fits-all’ formula when it comes to sleep.

“We’re all different,” Preeya says. “I know I need around eight hours’ sleep to feel refreshed. My husband only needs six or seven hours’ sleep and he’s ready to go. You tend to know your sleep sweet spot. For most adults, it’s around seven to nine hours a night.”

Deciding whether to go back to sleep when you wake up tired depends on the time of day, your sleep schedule, how much sleep you've already had and your plans. If it's close to your usual wake-up time, going back to sleep might disrupt your schedule, but if it's much earlier, you might benefit from more rest.

Types of sleep

Sleep plays a crucial role in our physical, mental and emotional wellbeing. There are two main types of sleep – REM, known as rapid eye movement sleep and non-rapid eye movement (NREM). Both are essential and the amount we need depends on our age and other factors.

REM sleep 

REM sleep is when we dream. During this stage, your eyes move rapidly. It's essential for emotional regulation, memory consolidation, and learning. The need for REM sleep varies across different age groups.

Kids 

Children require a substantial amount of REM sleep for brain development. Newborn babies spend half their time asleep dreaming, and this gradually decreases as they reach primary school age.

Teens

Teenagers need ample REM sleep for cognitive development and learning.

Adults

In adults, REM sleep is crucial for emotional regulation and processing emotions experienced in the day.

Seniors

The need for REM sleep remains important for emotional health and memory in seniors, and the good news is the amount of REM sleep we get as we age remains largely unchanged.

Deep sleep

Deep sleep, or slow-wave sleep, is the most restorative phase of sleep. It plays a critical role in physical recovery, tissue repair and the release of growth hormones. Like REM sleep, the amount of NREM sleep we need changes throughout our life.

Kids

Deep sleep is particularly important for growth and development. As kids get older, they spend more time in deep sleep and it often becomes more consolidated as they stop their daytime naps.

Teens

Adolescents need lots of deep sleep to support their growth and development. Some studies show teens who get adequate deep sleep tend to perform better in school and find it easier to regulate their behaviour.

Adults

Deep sleep is vital for muscle growth, tissue repair and overall physical health. It's also during deep sleep that the body's immune system is strengthened.

Seniors

The amount of deep sleep we need drops as we age, but it’s important we still get enough sleep to prevent the increased risk of serious health problems. Creating an environment conducive to quality sleep is important for seniors. 

“If you’re getting enough sleep, then you should ideally wake feeling refreshed,” says Preeya. “There are many things that can impact your ability to wake feeling like this. In most cases however, it’s lifestyle factors that are responsible for fatigue such as poor sleep quality or quantity, or poorly managed stress.”

There could be a number of reasons you’re getting enough sleep but still tired, including:

Hormones

A hormonal imbalance can impact your energy levels. For example, too much cortisol, the stress hormone, can zap you of energy and disrupt sleep. Hormonal changes can affect your energy too, such as during menopause.

Sleep apnoea

This is a condition where the throat gets blocked, either partially or fully, while you’re asleep. The loss of oxygen will wake you briefly, often without you even realising it. In severe cases, it can interrupt sleep hundreds of times a night, leaving you exhausted.

Mental health

Conditions such as anxiety, depression and bipolar disorder can lead to excessive tiredness. Talk to your healthcare professional if you’re worried about your mental health affecting your sleep.

Thyroid issues

Poor thyroid function can interfere with your sleep. Hypothyroidism in particular can make you feel tired more easily, even if you’re getting enough sleep.

Nutrient deficiencies

A lack of certain nutrients such as iron, vitamin B12 and vitamin D can leave you feeling fatigued.

Related: Improve your night-time routine for more energy

Medications

Certain medications, including antidepressants, stimulants, corticosteroids, decongestants and medications for hypertension and asthma can disrupt sleep patterns.

A lack of certain nutrients, such as iron, vitamin B12 and vitamin D can leave you feeling fatigued

It’s tempting to rely on a tipple or two to help you unwind in the evening. But, warns Preeya, despite how it may make you feel in the short term, alcohol can steal your chance of a good night’s sleep.

“Drinking alcohol regularly can negatively impact sleep quality and how you wake in the morning,” she explains.

Research shows alcohol can disrupt your circadian cycle, block restorative REM sleep, aggravate breathing problems like snoring, and even induce sleep apnoea. Plus, alcohol’s diuretic effect might cause extra bathroom breaks during the night.

Preeya says if you wake up feeling groggy you may need to look more closely at your wellbeing. “Many people don’t realise mood disorders can impact how you wake,” she says. “If you’re suffering from depression or anxiety you may not wake feeling refreshed, despite having enough sleep.” 

Preeya says a routine is vital to get a good night’s sleep. “I ask my patients to prepare the brain for sleep with a regular ritual.”

Preeya prescribes the following:

1. No screens an hour before bed

“This includes phones, so no Instagram scrolling, sorry!” she says. The blue light from screens blocks the production of melatonin, the hormone essential for sleep.

Related: Can blue light damage your eyes?

2. Reduce caffeine and alcohol

Skipping your afternoon coffee, particularly after 2pm, is likely to improve your sleep, as is cutting down, or out, the amount of alcohol you drink at night.

3. Get active

Aim for regular physical activity, ideally 30 minutes most days and in sunlight. “This helps circadian rhythms that regulate sleep,” she says.

For more tips and tricks to improve the quality (and quantity) of your sleep, check out our dedicated Sleep page on The Check Up.

4. Regularity matters

Sticking to a regular sleep routine, with consistent bedtimes and wake-up times, is key to keeping your body's internal clock in check to ensure a good night's sleep. It's all about fostering better sleep quality and overall sleep hygiene.

5. Embrace the morning light

Being exposed to morning sunlight has been found to boost your alertness for the day ahead. Spending time outdoors and soaking in natural light can lower melatonin levels, keeping you alert and your body's internal clock ticking smoothly.

nib foundation partner, the Black Dog Institute, offers a free, evidence-based smartphone app called Sleep Ninja®, which has been shown to be effective in helping young people with sleep problems. Based on Cognitive Behavioural Therapy for Insomnia (CBT-I), Sleep Ninja teaches strategies across six ‘training sessions’ to develop healthy sleep habits and improve sleep quality. For more information, head to the Black Dog Institute website.

Please note: The tips throughout this article serve as broad information and should not replace any advice you have been given by your medical practitioner.