How Many Hours Of Sleep Should You Be Getting?

Diet, exercise and sleep are the three elements fundamental to leading a happier, healthier and fitter life. And yet, millions of Australians aren’t getting enough hours each night.

In fact, recent research found about a third of Australians said they weren’t getting the recommended minimum of seven hours a night [1]. Most adults require between 7 and 9 hours each night to function at their best. Although the requirements of each individual will vary, it’s not recommended any adults get less than 6 or more than 10 hours [2].

Regardless of if you are training to improve your overall health and quality of life, gain muscle or lose fat, sleep plays an integral role in achieving these goals. It will help you feel better and improve your training and nutrition motivation, performance and results.

Why sleep is important for strength

You build strength by creating tiny tears in your muscles which are then repaired to be stronger. The majority of this process takes place while you are asleep. Therefore if you don’t get enough, your body may take longer or be unable to fully repair your muscles, leading to fatigue and compromising your strength.

Insufficient sleep has been linked to a drop in strength training performance. Studies show that acute deprivation, such as one bad night, doesn’t appear to impact on strength, but extended deprivation does. Consecutive nights with reduced sleep affect multi-joint, or compound strength exercises, such as the squat, deadlift and bench press [3]. This means you won’t be able to lift as much on your main lifts, however some of your single-joint accessory exercises may be unaffected [4].

Sleep plays an integral role in regulating your hormones, which impact muscle growth and repair and long-term health. As you sleep your body secretes a muscle-building growth hormone and your muscles relax, relieving tension and reducing pain [5]. On the other hand, deprivation prompts cortisol to be released, making it harder to build muscles. It also disrupts testosterone production and increases insulin resistance, which may limit muscle growth and repair [6].

How sleep affects fat loss

Sleep is not only important for losing fat, but also in keeping it off. Not getting enough shut-eye dulls activity in the frontal lobe, which is the part of the brain responsible for decision-making and impulse control. It also leads to increased cravings for energy-dense, high-carbohydrate foods and your reward centres ramp up, making it harder to say no. Add these together and you’re more likely to crave unhealthy foods and to give into these cravings [7].

But even if you’re managing to resist those cravings and achieve a calorie deficit, you still need to get enough shut-eye. To optimise your results and health, you should aim to decrease body fat while retaining as much muscle mass as possible. While much of this comes down to nutrition, sleep also plays a role. For example, one study found that participants who only slept 5.5 hours a night lost 55% less fat than those who got 8.5 hours. They also lost 60% more muscle [8].

Another placed participants on a calorie deficit diet and reduced the amount of slumber by just one hour a night on five nights a week. The study had similar results, with those with less rest losing less less fat and more muscle than those who were well rested. This suggests that simply catching up on the weekend isn’t enough to reverse the effects of mid-week deprivation [9].

The impact of sleep on your health

Sleep disruption has both short and long-term heath consequences. In otherwise healthy adults, consequences include stress responsivity, somatic pain, reduced quality of life, emotional distress and mood disorders, and decreased cognitive and memory performance.

Long-term consequences include increased risk of health conditions such as diabetes, weight-related issues, heart disease and stroke. There is also a relationship between deprivation and sarcopenia, which is the loss of muscle mass and strength as you age [10].

How much deep sleep should you get a night?

There are four stages of sleep, with each serving a different purpose. Deep sleep refers to the third stage and it is what makes you feel refreshed in the morning [11]. It is when your body recovers, blood sugar levels and metabolism balances out, immune system is energised, learning and emotions process and memories consolidate [12].

Every night, your body repeatedly moves through the four stages. The first episode of deep sleep lasts from 45-90 minutes and each subsequent episode gets shorter as the night progresses [13]. The average healthy adult needs between one and two hours of deep sleep across eight hours of sleep [14].

It’s about quality, not just quantity

Getting enough deep sleep is about more than just the number of hours spent in bed, it’s also about the quality. Signs your sleep quality need to improve may include feeling tired and irritable, difficulty falling and staying asleep and taking more than 30 minutes to fall asleep after you get in bed [15]. This may mean that even though you are spending enough hours in bed, you’re not getting the full restorative effects.

Circadian rhythms play a huge role in governing your quality. Your circadian rhythms are part of your internal clock which tells your body when to carry out different functions, including sleeping and waking. You may find it difficult to unlock high quality sleep if your circadian rhythm isn’t aligned with your routine [16].

However, there are plenty of things you can do to adjust your circadian rhythm and improve your sleep quality. The trick to quality is in consistency, through developing good habits.

Tips for developing good habits

Set a routine

Going to bed and waking up at the same time every day will strengthen your circadian rhythm. Even one night’s alteration can make it more difficult to fall asleep, so it’s important to be consistent [17]. Set yourself a one-hour period for when you will go to bed and make it realistic and attainable. Remember, everyone’s schedule is unique and your bed time needs to fit in with your lifestyle.

Set boundaries

Dedicate the hour before bed to winding down and relaxing. Activities such as reading (books, not work emails) will help prepare your brain for a good night’s rest.

Be aware of blue light

Technology such as computers and smartphones emit blue light, which interferes with your circadian rhythms. You can drastically improve your quality of rest by keeping your bed as a place for slumber – not for watching TV or scrolling mindlessly through social media [18].

Should you still workout if you’re tired?

Even though your energy levels will impact on your performance in the gym, it’s no excuse to skip a session. Instead, talk to your coach about how you can adjust your workout to facilitate recovery. For example, you may opt for less intensity in a session by lowering the weights. This will allow you to still access all the benefits of strength training but mitigate your body’s reduced ability to recover.

References:

[1] https://www.abc.net.au/news/science/2021-06-09/australia-talks-not-getting-enough-sleep-phones-to-blame/100161686

[2] https://www.sleephealthfoundation.org.au/how-much-sleep-do-you-really-need.html

[3] https://pubmed.ncbi.nlm.nih.gov/29422383/

[4] https://pubmed.ncbi.nlm.nih.gov/29422383/

[5] https://www.sleep.org/how-sleep-adds-muscle/

[6] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6262283/

[7] https://www.webmd.com/diet/sleep-and-weight-loss#1

[8] https://www.acpjournals.org/doi/10.7326/0003-4819-153-7-201010050-00006?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub%3Dpubmed&

[9] https://academic.oup.com/sleep/article/41/5/zsy027/4846324

[10] https://www.sleepfoundation.org/physical-health/diet-exercise-sleep

[11] https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Understanding-Sleep#2

[12] https://www.healthline.com/health/how-much-deep-sleep-do-you-need#takeaway

[13] https://www.sleephealth.org/sleephealthapp/learnmoreaboutsleephealthapp/

[14] https://www.healthline.com/health/how-much-deep-sleep-do-you-need#takeaway

[15] https://www.sleepfoundation.org/sleep-hygiene/how-to-determine-poor-quality-sleep

[16] https://www.sleepfoundation.org/circadian-rhythm

[17] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2718885/

[18] https://www.sleepfoundation.org/bedroom-environment/blue-light