Sleep. Most of us wish we had more of it. Yet it’s still. So. Elusive. And while yawning and feeling tired all the time can be a bummer, a lack of zzz’s can actually have a big impact on your health. Experts say you should aim to get between seven and eight hours of shut-eye each night, but is it really that important?
Short answer? Yes, and that’s a big YES!
Inadequate sleep (<7 hours), especially on a regular basis, doesn’t just make you drowsy, it can also affect short-term outcomes such as work or cognitive performance and increase cardiometabolic risk factors through effects on body mass, appetite, and energy expenditure. Insufficient sleep can also contribute to more serious long-term outcomes including cardiovascular disease (CVD), which may ultimately lead to death.
Unfortunately, there’s a lot that can interfere with natural sleep patterns. People are now sleeping less than they did in the past, and sleep quality has decreased as well.
Let’s take a closer look at why we sleep, along with what happens if we don’t get enough.
Why do we sleep?
A lot is still unknown about the purpose of sleep. However, it’s widely accepted that there isn’t just one explanation for why we need to sleep. It’s likely necessary for many biological reasons. To date, scientists have found that sleep helps the body in several ways. The most prominent theories and reasons are outlined below.
1. Energy Conservation
According to the energy conservation theory, we need sleep to conserve energy. Sleeping allows us to reduce our caloric needs by spending part of our time functioning at a lower metabolism.
2. Cellular Restoration
Another theory, called the restorative theory, says the body needs sleep to restore itself.
The idea is that sleep allows cells to repair and grow. This is supported by many important processes that happen during sleep, including:
- Muscle repair
- Protein synthesis
- Tissue growth
- Hormone release
3. Brain Function
The brain plasticity theory says sleep is required for brain function. Specifically, it allows your neurons, or nerve cells, to reorganize.
When you sleep, your brain’s glymphatic (waste clearance) system clears out waste from the central nervous system. It removes toxic by-products from your brain, which build up throughout the day. This allows your brain to work well when you wake up.
Sleep affects many aspects of brain function, including:
- Problem-solving skills
- Decision making
Have I convinced you yet that sleep is important?
If not, here are a few more important functions of sleep:
Sleep is necessary for emotional health
During sleep, brain activity increases in areas that regulate emotion, thereby supporting healthy brain function and emotional stability. Research shows that sleep and mental health are intertwined. On the one hand, sleep disturbances can contribute to the onset and progression of mental health issues, but on the other hand, mental health issues can also contribute to sleep disturbances.
Sleep assists with weight maintenance
Sleep affects your weight by controlling hunger hormones. These hormones include ghrelin, which increases appetite, and leptin, which increases the feeling of being full after eating. During sleep, ghrelin decreases because you’re using less energy than when you’re awake. Lack of sleep, however, elevated ghrelin and suppresses leptin. This imbalance makes you hungrier, which may increase the risk of eating more calories and gaining weight.
Sleep promotes proper insulin function
Insulin is a hormone that helps your cells use glucose, or sugar, for energy. But in insulin resistance, your cells don’t respond properly to insulin. This can lead to high blood glucose levels, and, eventually, type 2 diabetes.
Sleep may protect against insulin resistance. It keeps your cells healthy so they can easily take up glucose.
Sleep boosts immunity
A healthy and strong immune system depends on sleep. Research shows that sleep deprivation can inhibit the immune response and make the body susceptible to getting sick
When you sleep, your body makes cytokines, which are proteins that fight infection and inflammation. It also produces certain antibodies and immune cells. Together, these molecules help to protect your body from illness and disease.
Sleep protects your heart health
Sleep supports heart health. We can see this through the link between heart disease and poor sleep. People who don’t get enough sleep have a greater risk of heart disease and stroke. One study involving 461,347 people found that people who slept less than 6 hours a night- compared with those who slept 6 to 9 hours- had a 20% higher risk of heart attack!
Sleep Deprivation and Kidney Disease
Unfortunately sleep deprivation and sleep disorders are really common in people with CKD, with up to 80% of people with stage 5 CKD reporting sleep complaints. These sleep problems take a variety of forms and can take a serious toll on people’s health and quality of life.
Types of Sleep Problems
CKD sleep problems can take several forms. The most common are:
- Insomnia – trouble falling asleep, staying asleep, and/or early morning waking. Insomnia affects an estimated 30-70% of people with CKD.
- Restless legs syndrome (RLS) – an irresistible urge to move the legs, which is worse at night, and is temporarily relieved with movement. RLS is frequently associated with another movement disorder called Periodic Limb Movements in Sleep (PLMS). RLS affects 60-80% of people with CKD.
- Sleep apnoea – disordered breathing during sleep including periods of apnoea (not breathing), heavy snoring in most cases, restless sleep, fragmented sleep, frequent awakening, morning headache, personality or mood changes, and daytime sleepiness. Sleep apnoea affects around 50% of people with Stage 5 CKD.
Causes of Sleep Deprivation
There are various causes of sleep deprivation, which can be voluntary behavior, personal obligations, working schedules, or medical problems. One of the important causes of chronic sleep deprivation is a conditioned emotional response. That is thinking too much about sleep problems or feeling anxious about not getting enough sleep. These feelings can significantly impact normal sleep behaviors and prolong the period of sleep deprivation.
Things that can contribute to sleep deprivation include:
- Shift work
- Irregular sleep schedules
- Restless leg syndrome
- Sleep apnoea (untreated)
- Chronic pain
- Longer work hours
- Certain medications
Consequences of Sleep deprivation
In the past 15 or more years, research has overturned the idea that sleep loss has no health effects, apart from daytime sleepiness. Studies show us time and time again that sleep loss (less than 7 hours per night) may have wide-ranging effects on the cardiovascular, endocrine, immune, and nervous system including the following:
- Obesity in adults and children
- Diabetes and impaired glucose tolerance
- Cardiovascular disease and high blood pressure
- Anxiety symptoms
- Depressed mood
- Alcohol use
- Increased mortality from all causes
Many of the studies find graded associations, which means that the greater the degree of sleep deprivation, the greater the apparent adverse effect. Another common finding is the relationship that adverse effects occur with either short or long sleep duration, as compared to a sleep time of 7 to 8 hours. What this means is that negative health effects can occur both with too little sleep (below 7 hours) and too much sleep (above 8 hours).
Sleep Deprivation and the Kidneys
The relationship between sleep disturbances and CKD seems to go both ways. What I mean by that is that people with CKD are more likely to experience sleep problems AND sleep problems are linked to a faster decline in kidney function.
Multiple studies have shown that short sleep duration (less than 6 hours sleep) AND long sleep duration (typically more than 8 or 9 hours sleep) are both associated with an increased risk of developing CKD and progression to end-stage kidney disease.
The reason for this isn’t fully understood but it is likely to do with a variety of factors. Lack of sleep is associated with:
- High blood pressure
- ‘Non-dipping’ blood pressure – blood pressure that doesn’t drop during the night
- Increased sympathetic nervous system activity
- Dysregulation of renin-angiotensin-aldosterone system
- Increased inflammation
- Elevated cortisol levels
- Weight gain
- Insulin resistance and diabetes
All of these things have a negative effect on the kidneys and can increase the risk of both developing CKD and are involved in kidney disease progression.
Not getting enough sleep has also been shown to increase the risk of proteinuria (protein loss in the urine). In a meta-analysis involving over 280,000 people, sleeping 5 or fewer hours a night increased the risk of developing proteinuria.
Proteinuria is considered a strong risk factor for developing kidney disease and increases the likelihood of clinical progression of CKD. Proteinuria in people with CKD may accelerate kidney disease progression to end-stage kidney disease.
Are you sleep-deprived?
Sleep specialists say that one of the tell-tale signs of sleep deprivation is feeling drowsy during the day. In fact, even if a task is boring, you should be able to stay alert during it if you are not sleep-deprived. If you often fall asleep within 5 minutes of lying down, then you likely have sleep deprivation. People with sleep deprivation also have ‘microsleeps.’ These are brief periods of sleep during waking time. In many cases, sleep-deprived people may not even be aware that they are having these microsleeps.
Although sleep deprivation is estimated to affect one out of three people, it’s not easily diagnosed. The spoon test or the Sleep onset latency test is a simple home test that can be used to identify sleep deprivation. This test was developed by the late Dr. Nathaniel Kleitman from the University of Chicago, who is famously known as the ‘father of sleep research.’
Interested in giving it a go? Here’s how to do it:
Sleep Onset Latency Test
- A watch to measure time
- A metal spoon
- A metal tray
This test is to be carried out only during the daytime. Darken the bedroom and then lie down at the edge of the bed. Keep a metal tray on the floor beside the bed and hold a metal spoon over it. Note the time and close your eyes as if to sleep.
When you fall asleep, your hand will loosen its grip over the spoon and it will come crashing down onto the tray, waking you up. Immediately look at your watch and note how much time has passed.
If you fall asleep within 5 minutes, you are most likely severely sleep-deprived. If it took 10 minutes to fall asleep, you likely need more sleep than you are getting now. If you were awake for 15 minutes or more before falling asleep, then you are probably getting adequate good sleep regularly.
An Alternative Method
Dr. Michael Mosley, a physician, and author suggests a simpler alternative to the spoon test. He advises setting an alarm for 15 minutes so that you can note whether sleep happens within that time. If you’re still awake when the alarm goes off then you’re less likely to be sleep-deprived.
Recovering from Sleep Deprivation
If you don’t get enough sleep, there’s only one way to compensate- getting more sleep. It won’t happen with a single early night. If you’ve had months (or in some cases years) of restricted sleep, you’ll have built up a significant sleep debt, so expect recovery to take several weeks.
Treating sleep as a priority, rather than a luxury is an important step in reducing sleep deprivation, preventing a number of chronic medical conditions, and looking after your kidneys.
Tips for Improving Sleep
Firstly, it’s important to determine whether you’re suffering from a sleep disorder like sleep apnoea or restless legs syndrome because the treatment of these sleep disorders is different from those suffering from insomnia or sleep deprivation.
- Take time to wind down- the goal is to be in a parasympathetic state at bedtime, so you need to give yourself a chance to wind down before getting into bed. Do a relaxing activity in low light and avoid task-orientated activities. Also, our brains work well with routine so following the same bedtime routine helps our brains recognize when it’s time to sleep.
- Limit light at night- the type and brightness of light we’re exposed to in the hour before bed can suppress melatonin (sleep hormone) production. Keep all devices out of the bedroom because this is associated with worse sleep and use blue light-emitting glasses or apps in the hours before bedtime to allow melatonin to increase.
- Try to go to bed at the same time each night and wake up at the same time each day
- Avoid caffeine, alcohol, and nicotine
- Exercise no later than 3 hours before you go to bed
- Stop eating at least 3 hours before going to bed
- Avoid naps outside of 20-minute power naps during the day
- Practice relaxation techniques or breathing techniques in bed to help you relax
- Make sure your bedroom is set up for good sleep:
- Cooler than 18 degrees Celsius or 65 degrees Fahrenheit
- Comfortable sleeping surface
- No wakeful stimuli ie. Devices docked in another room
- Door closed
- Get out of bed if you can’t sleep- if you haven’t been able to sleep after 20 minutes, get up and do something quiet (and boring) in dim light until you’re tired and then try again
- And in the morning:
- Get sunlight for 30 minutes in the first 1-2 hours of waking to increase melatonin levels at night
- Get 10-minute bursts of light every couple of hours
Supplements to help with sleep
Changing your routine and working on the sleep hygiene measures I’ve mentioned may be enough to get your sleep back on track but for those of you who are still struggling, adding in some specific supplements may be helpful:
- Melatonin – often referred to as the sleep hormone, helps us fall asleep and stay asleep during the night. Low levels of melatonin make it harder to fall asleep so it can be taken as a medication or supplement to help regulate our circadian rhythm and get our sleep-wake cycle back on track. Studies have shown that the production of melatonin is impaired in people with CKD which may be part of the reason people with CKD have a greater degree of sleep disorders than the rest of the population.
- Magnesium – insomnia is a common symptom of magnesium deficiency. People with low magnesium often experience restless sleep and wake frequently during the night. Supplementing with magnesium can increase sleep time, sleep efficiency, increase melatonin levels, improve sleep onset, reduce cortisol levels and reduce early morning waking.
- Glycine – glycine is an amino acid. Research in people with sleep issues has shown that when taken before bed it can decrease how long it takes to fall asleep, improves sleep quality and promotes deeper, more restful sleep, and lessens daytime sleepiness.
- Valerian Officinalis – Valerian is a sedative herb that helps reduce the time it takes to fall asleep, reduces restless sleep, and promotes more refreshing sleep. One of the great things about Valerian is that it doesn’t cause a hangover effect that can occur with sleeping tablets or sedative medications.
- Chamomile – Chamomile tea is a great addition to your nighttime routine. Chamomile contains apigenin, a chemical compound that binds to the GABA receptors in your brain, the same receptors that benzodiazepines like Valium bind to (medications commonly used for anxiety and insomnia). It has a sedative and relaxing effect so is helpful for people who have trouble falling asleep at night.
Make sure you discuss any new supplements with your healthcare provider first before starting on them.
A good night’s sleep is incredibly important for your physical and mental health. In fact, it’s just as important as healthy eating and exercising. Sleep problems are becoming increasingly common and because of that, it can be easy to fall into the trap of thinking it’s ‘normal’ to have trouble falling or staying asleep. Well, I’m here to tell you that just because it may be common, doesn’t mean it’s normal and it’s definitely not benign.
If you want to heal your kidneys, it’s really important that you’re taking care of ALL aspects of your health and sleep is a really big part of that.
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