Millions of Americans will delight in the luxury of getting a few hours of extra sleep over the Christmas holiday weekend – but may not realize they’ll likely pay the price later on.
Sleeping longer than the recommended seven or eight hours every night, while it seems like the best bet for recovering from a busy week at work or the madness of preparing for the holiday, actually causes more grogginess and low energy throughout the day.
Each sleep cycle starts over every 80 to 100 minutes, so adding an hour or more to a night’s sleep typically means waking up in the middle of a deep sleep cycle, resulting in a post-hibernation hangover.
There are four sleep cycles, but waking up during the third, when sleep is deepest, will have the greatest influence on how someone feels in the daytime. After the third cycle comes REM, or the rapid eye movement cycle, which is when we dream.
Getting too much sleep, like too little sleep, can cause a litany of health problems, from headaches, depression, and low productivity to an elevated risk of chronic heart disease, diabetes, and obesity
The harmful effects of sleep deprivation are similar to those linked to sleeping too much, including a weakened immune system and risk factors for heart disease such as high blood pressure and inflammation
The brain cycles through two different types of sleep – REM and non-REM, which includes the early stage, when a person just begins to fall asleep, followed by light sleep, when the heart rate and breathing are regulated and body temperature drops.
The third stage is deep sleep when the brain can consolidate new memories and commit them to long-term storage.
This phase is characterized by slow electrical waves that, on a monitor, look like unevenly spread-out rolling hills as opposed to the tightly packed crests and valleys that represent brain waves during wakefulness.
In REM, or rapid eye movement sleep, the electrical activity looks similar to an awake brain. During REM sleep, the brain continues to consolidate those memories and solidifies them into long-term memory. It is also the phase in which most dreams happen.
Doctors can detect when a person is in REM by examining facial twitches, eye movement behind the eyelids, and jaw tension.
The first cycle of REM sleep is the shorted, about 10 minutes. But each cycle gets longer with the greater amount of time spent asleep.
A person’s brain typically resets the cycle four or five times every night. Cycles typically last an average of 90 minutes, making the optimal duration for sleep around seven and a half hours.
Dr Alexandria Reynolds, a sleep researcher and psychologist at the University of South Carolina, said: ‘If you were to wake up while you were in deep sleep, you would wake up feeling super groggy, super confused, and whoever woke you up might not be safe.
‘If you were to wake up when you’re in REM sleep then you feel much more rested, ready to tackle the day, and you’ll feel pretty good.’
This is because during REM sleep, the brain is very active. It’s why vivid dreaming takes place during the REM stage, making the transition to wakefullness smoother.
Dr Reynolds added that on those mornings when a person wakes up on their own an hour before their alarm goes off should think twice before rolling over for that extra hour of sleep and instead get up and start the day.
‘You go back to sleep, you roll over, your alarm clock wakes you up and then you feel like trash… You really should have gotten up. You were oversleeping when your alarm clock woke you up,’ she said.
But getting the recommended number of hours every night is easier said than done, and normal life can get in the way, whether in the form of a heavy workload or a mad dash to prepare for Christmas festivities.
The freedom of work-free weekends often lulls people into the false sense of belief that snoozing for longer on Friday and Saturday nights will make up for their sleep deficit during the week. But experts maintain this simply is not how sleep works.
The more a person lacks sufficient sleep over time, the more they rack up sleep debt, the harder it is to pay it off.
They have long said that one cannot compensate for lost sleep by snoozing more on their day off. When a person does sleep for an additional hour or more into a Saturday or Sunday morning, they typically struggle to fall asleep on schedule Sunday night, perpetuating the sleep debt cycle.
Dr Jeffrey Iliff, a sleep and traumatic brain injury researcher at the University of Washington, said: ‘The sleep that you lose is sort of gone forever and many of the benefits of that sleep – that’s memory consolidation or whether that’s rejuvenation that happens in the brain – you sort of miss the boat.’
Research has shown that it can take up to four days of adequate sleep to recover from just one hour of lost sleep and up to nine days of good sleep to completely wipe out sleep debt.
Experts recommend people avoid exercise, heavy meals, alcohol or caffeine directly before bed, keep a consistent sleep schedule and avoid afternoon naps to help prevent sleep fragmentation, which puts them at an increased risk of developing cognitive issues down the line
A 2003 study performed at the Walter Reed Army Institute of Research put the weekend sleep catch-up method to the test.
In the study, 66 people spent either three, five, seven, or nine hours asleep every night for a week, followed by three days of eight hours of sleep.
Over the week, each participant underwent motor reaction speed and attention tests. During the three-day recovery phase, those who rested for seven and five hours continued to perform as poorly on the tests after several nights of longer sleep as they did during the week with poor sleep, showing no significant improvement.
The group with three hours of sleep saw their motor and attention skills improve after the first night of normal sleep, but their performance was not fully restored to normal and stayed similar to the seven and five-hour groups.
Getting too much sleep, like too little sleep, can cause a litany of health problems, from headaches and low productivity to an elevated risk of chronic heart disease, diabetes, and obesity.
Sleeping for longer than eight hours per night has also been linked with various mental health issues, including anxiety and depression. About 15 percent of people living with depression are oversleepers.
While oversleeping can lead to negative health outcomes, it can also be indicative of an underlying condition, including sleep apnea that causes poor quality of sleep throughout the night or hypersomnia, a condition in which people have excessive daytime sleepiness.
But, Dr Reynolds said, ‘We don’t know the direction of causality until we do more experimental studies.’
Experts recommend keeping to a sleep schedule with a goal of snoozing for around the same length of time consistently without over-indulging a few nights a week.
Napping is a good option, but there is such as thing as ‘good’ napping and ‘bad’ napping.
Dr Iliff said: ‘When you wake up after a nap and you feel like you just got hit by a truck, it’s because what has happened is you started to build what’s called sleep inertia.
‘Once you start sleeping, after you get past a certain point, your brain gets into the mode that thinks, “oh, we’re doing this for the next eight hours.” and if you interrupt it after it’s gotten past that point it’s sort of a rude awakening.’
Experts recommend napping for a short period of time, around 25 minutes, or a longer 90 minute nap, which is enough time for the brain to go through an entire sleep cycle.
