Do you feel increasingly tired over the working week and then sleep in on weekends? This is one of the surest signs that you’re sleep deprived most of the time. Many people fill their daily schedules so much that they simply have no time to sleep enough. And how much sleep is enough? Scientists say healthy adults need between 7 and 9 hours – teenagers a little more, and the elderly slightly less. Women usually need more sleep than men.
Catching up on sleep can be a good idea in some situations – for example, if you’ve had one night of shortened sleep, you can simply take a nap and then make sure your sleep schedule is ‘neat’ in the following days. But if you are constantly sleep-deprived, then those two, three, or more extra hours over the weekend won’t do much for your health nor for your sleep habits.
How does sleep work and what does sleep deprivation do?
You go through four sleep stages every night. They are repeated cyclically. All sleep stages (two light sleep stages, deep sleep, and REM sleep) are equally important for our overall health – the immune system, mood, memory, heart, and metabolism.
In the first half of the night, we have more deep sleep (also called slow-wave sleep), which is the most restorative. Deep sleep is very ‘sensitive’, so things like chronic sleep deprivation, alcohol or excessive stress can ‘block’ it – causing a person to have non-restorative sleep.
In the second half of the night, we experience more REM sleep, which is characterized by the rapid eye movement and vivid dreams. REM sleep helps balance our emotions and strengthen our memory. When you shorten your sleep and wake up too early, you might be cutting back on REM sleep.
In between, we have periods of light sleep – and we spend about 50% of our time in it. Light sleep prepares us for the transition between different sleep stages; during this sleep, our motor memory is consolidated. When we are sleep deprived, the body seems to prioritize deep sleep and REM over light sleep, so we usually make up the most of those two stages, while cutting back on light sleep.
When we are sleep deprived, we are moody, unable to focus, and our hormones are disrupted. People who are not well-rested are bad and dangerous drivers, and it’s almost certain that tiredness will cause us to make poor decisions.
Long-term consequences of sleep deprivation include serious psychological problems, heart disease, sleep disorders, obesity, insulin resistance, and many more.
Catching up on sleep over the weekend
Many adults get exhausted over the week and try to make up for it at the weekend. If you are one of them, you might be thinking there’s nothing wrong with this kind of behavior – you lose sleep, and then you get it back. Research shows this is not the case. You can get something back, but not all that you’ve lost.
A group of researchers wanted to know if people who were sleep-deprived (6 hours of sleep) for five days, and then slept in at the weekend would regain all the deficits that appear after sleep restriction. The study was conducted on thirty healthy people. After having four nights of recommended 8-hour sleep, they had six nights of shortened sleep. Then, they were given a three- day period of recovery sleep opportunity.
Their daytime sleepiness kept increasing over the period of restricted sleep and was brought to normal after two recovery days. The levels of their stress hormone cortisol dropped (compared to the beginning of the study) only after two nights of good sleep. As their cortisol was already high when the study began, it was concluded that the participants had already been deprived of sleep. So far, two important things have been proven to turn to normal – which is great.
However, the weekend recovery sleep didn’t help with regaining the attention levels. Unfortunately, although this was just partial sleep deprivation, participants’ attention decreased significantly, getting worse with time. Also, it’s not possible to fully restore lost health.
Therefore, a weekend’s recovery can help with some sleep deprivation consequences, but not all.
Is napping a good way to recover lost sleep?
Napping after only one night of sleep deprivation can definitely reverse some of the sleep-loss problems. It depends on how long your nap is. If you take a short 10-20 minute nap, it’s likely that most of it will be in light sleep. Take a longer, 90-minute nap to allow yourself enough time to finish one sleep cycle and go through all sleep stages.
Naps combined with a longer night’s sleep seem to work even better.
However, chronic sleep deprivation can’t simply be ‘fixed’ with naps. It’s a serious problem which affects health, inflammation, metabolism, hormones, blood pressure and more. Long-term sleep insufficiency requires huge changes in sleep habits – it especially means establishing a routine.
Am I sleep deprived without knowing it?
An easy way to check is – give yourself the opportunity to sleep in for a couple of days. If you still wake up early, you should be fine. However, if you do sleep in, then your body is trying to repay for sleep debt and you should consider changing your sleep hours.
You might think that 6-7 hours of sleep is all you need, but the truth is that just a small percentage of people can pull this out with no consequences. Many are just sleeping too little, wrongly believing that’s enough.
How do we deprive ourselves of sleep?
Some people accumulate sleep debt when they are at university and study at night, some when working in changing shifts, some are too busy, and some are just poorly organized. Also, going out and staying up late is what makes things really difficult for our circadian rhythm (biological clock), which relies on light as a cue – this is the only way your body can know what time it is. If you keep confusing your brain, you aren’t likely to get a good night’s sleep.
It is not impossible for people to go through life with excessive daytime sleepiness, not being aware they have a sleep disorder. For example, people are usually not aware they suffer from obstructive sleep apnea (OSA). It mostly affects obese males, who have difficulty breathing while they sleep. Sometimes their breathing pathways close, which causes frequent night awakenings. The sufferers are unlikely to remember ever waking up.
Keeping a routine in your sleep schedule and consulting a doctor if you suspect to have a sleep disorder are some of the best decisions you can make when it comes to your sleep habits and health.
- Repaying your sleep debt. Harvard Health Publishing. May 9, 2018. https://www.health.harvard.edu/womens-health/repaying-your-sleep-debt Accessed February 22, 2019.
- Breus, M. J. Fact or Fiction: You Can Catch Up on Sleep Over the Weekend. Psychology today. November 17, 2009. https://www.psychologytoday.com/us/blog/sleep-newzzz/200911/fact-or-fiction-you-can-catch-sleep-over-the-weekend Accessed February 22, 2019.
- Pejovic S, Basta M, et al. Effects of recovery sleep after one work week of mild sleep restriction on interleukin-6 and cortisol secretion and daytime sleepiness and performance. American journal of physiology. Endocrinology and metabolism. October 1, 2013. https://www.ncbi.nlm.nih.gov/pubmed/23941878 Accessed February 22, 2019.
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