Our Blog


At Advanced Cardiovascular Sleep Disorder Center in Auburn, AL, we always want to keep our clients informed. Check out our blog entries on the latest news and developments regarding sleep disorders.

Five commonly confused or misunderstood sleep terms

December 6, 2017 0 Comments

"Tyler (Insomnia)" by HappyManDomo (2010) (CC BY-ND 3.0)

[by Tamara Sellman RPSGT CCSH for Advanced Cardiovascular Sleep Disorders Center] 

Current recommendations from the National Sleep Foundation state that the average adult should sleep between seven and nine hours of sleep every night to maintain good health. Anything less than seven hours amounts to sleep loss.

How we define that sleep loss can be a matter of semantics.

Is is sleep deprivation? Sleep debt? Sleep restriction? Insomnia? Insufficient or inadequate sleep?

Knowing the difference will help you to take the next step to solving these issues with your sleep.


What is Sleep Deprivation? 

This terms describes sleep loss on a night-to-night basis. You can be sleep deprived one night, then go to bed earlier the next night (or nap during the day) and "catch up" on lost sleep. However, many nights in a row of lost sleep leads to something called "sleep debt." 

Sleep deprivation is a fairly loose term as it describes sleep loss for any reason. You might:

  • have had insomnia for a few nights in a row during a stress time in your life.
  • work a night shift that keeps you up until the wee hours of the morning, yet need to awaken to help your kids get off to school the next day.
  • suffer from an undetected sleep disorder: sleep apnea and periodic leg movement disorder, or PLMD, are two common ones that can go undetected for years.
  • enjoy a teeming social life that cuts into the time when you should really be sleeping.
  • experience chronic pain, which can cause sleep loss; what's worse, sleep deprivation can heighten one's pain threshold, making it even harder to sleep.
  • drink coffee in the afternoon or alcohol in the evening without realizing these are two very common sleep hygiene issues that result in lost sleep. 

What is Sleep Debt?

Like financial debt, sleep debt suggests you haven't "put enough sleep in the bank." However, sleep debt doesn't exactly work like financial debt.

With financial debt, you pay an interest on loans. However, you almost always have the opportunity to pay off your debt and start from square one. 

With sleep debt, you pay a tax on lost sleep with physical and mental health problems that require sleep to overcome. However, because your circadian rhythms need to stick to a schedule, paying off sleep debt isn't as simple as sleeping an extra dozen hours on the weekend. That will throw your circadian system offline and then you will have even more problems getting adequate sleep. 

A short period of sleep deprivation (say, over a week or two) may accrue as sleep debt, but with a little vigilance in sticking to a healthy sleep schedule and practicing sleep hygiene, you can overcome your debt. But if you are sleep deprived over months, getting adequate sleep itself won't be such an easy reset. Sleeping extra hours pay off longstanding debt, especially if you've developed other health problems that are related to sleep loss, such as hypertension, a mood disorder, or diabetes.

What is Sleep Restriction?

This term has two separate meanings: 

Sleep restriction due to lifestyle

When you choose to do things in your life that lead to fewer hours of sleep at night, that is a form of voluntary sleep restriction. You may opt for a night job, or you might be a student with lots of homework that keeps you up at night. A busy social calendar might impose itself on your nightly sleep. Though not necessarily by choice, new parents experience sleep restriction when they get up at night to soothe a crying baby. People with aging parents who step up to care for them might find they lose sleep due to this new role.

Sleep restriction as a therapy

Cognitive behavior therapy for insomnia (CBT-i) might employ a technique known as sleep restriction. It's an intentional sleep scheduling practice you follow under the supervision of a therapist for the purpose of resetting your circadian rhythms.

It can also be employed to solve some issues with sleep debt. It may also be a useful tool for people who have worked night shift for years but who are no longer doing so and need to return to a normal sleep-wake schedule.

Also, some insomniacs or people with distressing circadian rhythm sleep disorders like severe advanced or delayed sleep phase disorder (ASPD or DSPD, respectively) or non24 may need to cleave to a sleep restriction protocol in order to achieve adequate sleep.

In all of these cases, you are best advised to practice sleep restriction under the safe guidance of a counselor or sleep professional.

What is Insomnia?

Who hasn't had trouble falling asleep from time to time? Insomnia, generally speaking, refers to problems falling asleep or staying asleep. When people struggle to sleep even when they have every opportunity to do so, this form of sleeplessness is involuntary (unlike sleep restriction).

Acute insomnia occurs in response to stress or sleep hygiene issues. Usually, this form of insomnia goes away on its own once the root cause is addressed.

Chronic insomnia is defined as struggling to fall or remain asleep at least three nights a week over a consecutive period of time that is longer than three months. This is considered problematic as it contributes to sleep debt and its fallout, such as physical and mental health problems.

Typically, chronic insomnia indicates an undetected health problem that requires immediate attention, and is not, in itself, usually a primary occurrence. For instance, recent studies of people who have suffered from years of insomnia and who have not responded to sleep aids showed that the vast majority of them had a undetected and untreated sleep breathing disorder. [Read about the research here.]

Chronic sleeplessness can also be caused by a number of other health concerns, such as PTSD or recovery from a heart attack.  

What is Insufficient, or Inadequate, Sleep?

These terms simply mean you didn't get the recommended seven to nine hours of sleep the night before. Simply put, less than seven hours is not enough sleep to maintain optimum health: it is insufficient, or inadequate.

These forms of sleep loss don't seek to define the cause. But we all know how we feel when our sleep is insufficient or inadequate. We find we are sleepy during the day, we make mistakes at work or in school, we can be clumsy, and maybe even find ourselves drowsy behind the wheel of a car. 

Sleep loss, however it is defined, is concerning

How we define sleep loss makes a difference. These terms mean different things to sleep health professionals. Knowing how to describe your sleep loss will help you become more savvy about your sleep loss problems. It means you are able and willing to identify the root cause of your sleep loss. That's half the battle! Using the terms correctly also gives your health practitioner some insight into how they can help you sleep better, and shows them you are being proactive about your own health.

Have questions about these terms? Post your question in the comments below... we're happy to help you!


Photo credit: "Tyler (Insomnia)" by HappyManDomo (2010) (CC BY-ND 3.0)

No comments for this post

Add a comment