Originally published 21 September 2018. Last updated 18 November 2020.
My family has taken pictures of me asleep on the couch in the evening. This usually happens to me after a particularly long week. Usually, the pictures also include my cat resting on me while I sleep. He likes to leech my body heat when I’m sleeping.
Luckily, me falling asleep on the sofa late in the evening doesn’t happen all that often. This is because when this happens late in the evening, it can impact the quality of your sleep. And when sleep gets interrupted, it can lead to potential negative health effects.
Taking regular afternoon naps, on the other hand, can promote health. This is because when you nap, your body is not preparing for that 7 to 9 hour hibernation. But if you fall asleep on the couch later in the evening, your body might think that it’s hibernation time. It’s preparing for you to sleep for 7 to 9 hours. It’s this long, deep, restorative sleep that our bodies need so badly. This is what helps us perform at our best when we wake up. If you interrupt it by getting up and going moving yourself to your bed, it may influence the overall quality of your sleep.
Animals, like cats and dogs, can achieve this state of deep restorative sleep really quickly. That’s partly why they don’t need to sleep for 7 or 8 continuous hours at a time like we do. They can take a quick snooze or “cat-nap” and be back up on their feet and ready to go after just 10 or 15 minutes of rest.
The Stages of Sleep
As human beings we have 2 stages of sleep that our bodies fluctuate in and out of throughout the night. There’s the Rapid Eye Movement (REM) phase and the Non-Rapid Eye Movement (NREM) phase. To make things just a bit more complicated, the Non-Rapid Eye Movement phase actually has 4 stages, where stages 1-2 are what we would call “light sleep” and stages 3-4 would mean the person is in “deep sleep.”
When someone is in stages 1 and 2, the slightest sound might wake them up. But in stages 3-4, it may be harder to wake them up.
Stages 3-4 are most important for our health. In case you’re wondering how scientists identified these stages, they had people come into a sleep lab where they hooked them up to these machines that read their brainwaves and body temperature while they slept.
That’s just NREM sleep. REM sleep is also important for feeling your best. For most of us, it takes about 90 minutes to get to this phase of deep sleep. Remember how a quick nap is so restorative for our pets? Well, we’re built quite differently. We need a minimum of 7 hours to allow our bodies to go in and out of all the stages of NREM and REM sleep. When that happens, we wake up feeling refreshed.
The Health Effects of Interrupted Sleep
Why did I bother explaining all of that? You needed to know some of this background information to truly understand this concept.
We’re learning that when there are interruptions to the progression of these stages–for example, if you fall asleep on the couch before bed and get up to move to your bed–our hormones begin to change. These hormones range from those related to stress, appetite, and even growth hormone.
Interrupted Sleep Affects Your Appetite
In fact, researchers have discovered that fragmented slumber may be more important than sleep duration for regulating appetite. In other words, if our sleep gets interrupted, we may end up eating more the next day. Some believe that this happens because the body is somehow trying to compensate; increasing food intake tends to promote sleep.
Interrupted Sleep Affects Your Stress Levels
Sleep researchers have also found that interrupted sleep can increase stress hormone levels in the blood. An increase in stress hormones can lead to other not-so-great health effects like:
- increased fat storage (particularly around the abdomen)
- decreased sensitivity to insulin (which may increase the risk for developing Type 2 diabetes)
- poorer brain functioning
- an immune system that doesn’t work as well
Interrupted Sleep and Your Overall Health
Other researchers have found that disrupting sleep for even just a few seconds leads to a temporary increase in heart rate and blood pressure. The body thinks that it’s time to wake up and tries to get your heart rate and blood pressure back up to the levels it normally experiences when you’re awake.
If sleep gets interrupted over and over, this increase in blood pressure may become permanent. This is one of the reasons why it’s been theorized that interrupted slumber may lead to high blood pressure or hypertension.
How Alcohol Affects Sleep
Depending on the amount of alcohol consumed, alcohol can act as a “depressant.” No, this doesn’t mean that by drinking it you will feel “depressed.” It simply means that it tends to slow down the body and mind. Caffeine, on the other hand, is called a stimulant in that it would have the opposite effect–it speeds things up.
Many folks will claim that alcohol makes them feel sluggish or sleepy. Because of this effect, they may use alcohol to help put themselves to sleep. After all, that’s what “nightcaps” are for, right? Well, this is partly true. Alcohol can make you fall asleep faster. But some have a lower tolerance to this effect, where others may have a higher tolerance. You may have a lower tolerance to alcohol while others may not have quite the same response–maybe they can consume more alcohol and not fall asleep as quickly or feel as groggy the next day.
The Rebound Effect
Here’s the really interesting thing: regardless of whether you have a high tolerance or a low tolerance to alcohol, while you’re asleep, your body is still metabolizing that alcohol and clearing it from your system. At some point during the night, while you’re asleep, something called a “rebound effect” happens. This means that instead of acting as a depressant like it normally would, once the alcohol clears your system, your body starts to wake up. And if you’re an otherwise healthy person with a normal functioning liver, this can happen 4-5 hours after you fall asleep (depending on how much alcohol you consumed before you hit the hay).
Think about it–the body is starting to wake up right in the middle of your sleep cycle! This is when you’re supposed to be moving in and out of stage 2 of non-rapid eye movement and REM sleep!
Sure enough, this is what scientists have discovered. When alcohol is consumed before bedtime, the body spends less time in the REM phase of the sleep cycle. You end up feeling tired and groggy the next day as a result, even though you may have slept for the recommended 7-8 hours. Added to this is the effect that alcohol may have on hormones, like growth hormone. Alcohol may decrease the amount of growth hormone secreted during sleep–that will definitely influence any gains you were hoping to achieve from your workout earlier in the day.
I know–all of this news doesn’t sound great. In fact, it can be pretty distressing. If we start obsessing over the minutes of sleep we’re losing every night, that may cause us to lose even more sleep!
What I recommend: when you start to feel sleepy, move to your bed before sleep sets in.
Getting off the couch to tuck yourself into bed may wake you out of the state of sleepiness you were experiencing, but If that happens, have a snoozy-time book on your nightstand–one that’s not super-interesting–and start reading. That should get your mind and body back into sleep mode.
Is Sleep or Exercise More Important?
As for sleep and exercise: is one more important than the other?
There simply does not seem to be enough hours in the day to accomplish both sleep and exercise. Yet both are super important for long-term health and wellness.
You may have heard that most adults need 6-8 hours of sleep each night. We’re learning that, for most healthy adults, a minimum of 7 uninterrupted hours of sleep each night is the sweet spot. Sleeping for 7 hours each night allows the body enough time to go in and out of deep, restorative sleep (often called REM sleep) which helps repair and replenish the body’s cells, especially the immune system (our body’s natural defense against harmful bacteria and viruses).
Benefits of Exercise
We also know that regular exercise is vital for overall health and wellness. Long-time listeners of my podcast can probably list at least 5 reasons exercise is so beneficial:
- it keeps your heart healthy
- it improves mood
- it reduces systemic inflammation
- it keeps your brain young
- it helps you sleep longer and deeper
That’s right! Regular physical activity helps you fall asleep faster and stay asleep longer.
Benefits of Getting Enough Sleep
Now check out the health benefits of getting adequate sleep and see if there are any that sound familiar.
- it keeps your heart healthy
- it improves mood
- it reduces systemic inflammation
- it keeps your brain young
Hmm… But at the same time, if you don’t get a good night’s sleep, you won’t be motivated to exercise. So it’s no surprise that both of these behaviors are very dependent on each other
Many will often sacrifice their sleep in order to squeeze in a workout. For example, you may wake up after only 5.5 hours of sleep to go to the gym before heading off to work or school. Or you may end up only getting 5.5 hours of sleep because you went to bed late the night before to squeeze in that evening run.
Here's my bottom line: I would place getting adequate sleep just slightly above exercise. Again, only slightly.
Why Sleeping Has a Slight Edge
Getting those 7 uninterrupted hours of solid sleep may prevent damage to muscles and will reduce your risk for injury when you are working out which gives sleep a slight edge. But that doesn’t mean that you should skip being active completely.
Remember: the Surgeon General admits that breaking up your activity into small increments throughout the day still leads to health benefits. So even if you don’t have time to get in that 30 min workout, taking the stairs instead of the elevator still counts towards your physical activity for the day. Walking to and from class counts. Doing chores around the house counts.
All of these add up to your physical activity quota and still provide health benefits.
Ways to Get In More Exercise
What if you’re looking for something a little more intense?
The other day, I was running late for a meeting but I knew I wanted to squeeze in a quick workout before I headed to the office. I used to be one of those melodramatic fools that believed if I’m not spending at least 45 minutes at the gym, then I’m not getting in a good workout. But I’ve come to learn how wrong I was.
So when I was running late for a meeting the other day, I finished a 7.5 minute workout at home… with no equipment. And I was completely gassed! The workout took only 7.5 minutes and yet I felt so accomplished… and I got in a solid workout.
If you’re strapped for time, run a mile as fast as you can. For most folks, it should take you no more than 8 minutes. Boom, you’re done. Hit the showers and go on with your day.
HIIT workouts are something you could easily work into your day, too.
How Do I Know If I Did Enough Exercise?
How do you know whether the activity you just finished was worthwhile?
Ask yourself these two questions:
- Am I breathing heavily? If yes, perfect. If you’re breathing heavily, it means your heart is working hard.
- Do any of my muscles feel fatigued? If yes, then, you’ve worked those muscles adequately.
Getting in some solid physical activity does not have to come at the expense of getting enough sleep.
There are enough hours in the day to accomplish both… you just may have to be a little creative.