What is “normal” Deep Sleep?

User Question: 
Is it okay if Deep sleep occurs in short, 5-10 minute segments scattered throughout the night, instead of just a few longer segments during the first few hours of sleep, if the total amount of deep sleep is still in the typical range for my age?
Short Answer : 
There’s a lot we still do not understand about sleep, including exactly how to make sense of the vast range of individual differences in people’s sleep patterns. However, we do know that a scattered Deep sleep pattern in adults is sometimes associated with sleep-related breathing disorders and related health conditions, especially if the pattern is linked with feelings of sleepiness during the day.

Deep sleep is restorative, but different people need different levels of sleep. As Captain Barbossa from Pirates of the Caribbean said, the rules of sleep are “really more like guidelines.” For example, African-Americans get on average half the deep sleep that Euro-Americans get.  The elderly and the obese also see less deep sleep than healthy adults.

What’s the typical deep sleep pattern? For children and adults, the pattern usually includes a large chunk of deep sleep in the first portion of the night, followed by progressively smaller chunks, or none at all, with each of the following sleep cycles.

This pattern tends to break down with age. Aging adults are more likely to see their diminishing levels of deep sleep spread out more evenly throughout the night.

Sleep Quality and Quantity vs Age – Data Pulled from the Zeo Sleep Research Center Database

The pattern is also not guaranteed for those with a sleep-related breathing condition like sleep apnea. In  these cases, frequent awakenings from pauses in breathing cause sleep fragmentation, preventing deeper levels of sleep to be achieved. Patients with obstructive sleep apnea take longer to get deep sleep, and have less restorative sleep in general.

Even mild cases of breathing disorders during sleep can disrupt ordinary sleep patterns, leading to less time in restorative sleep.

Also, fragmented deep sleep is sometimes associated with parasomas, those strange sleep disturbances such as sleep walking, sleep talking, and night terrors. In these instances, the culprit may be fragmentation as well as unusually strong brain waves that prevent the sleeper from waking up easily.

So is Deep sleep not as restorative if it’s spread out across the night, (and you don’t have symptoms of sleep apnea or other health conditions)?

Honestly, we don’t know.

One of the functions of deep sleep is to release important hormones to the blood, including human growth hormone (HGH). In general, the amount of Deep sleep you get is correlated with how much HGH is produced. We make more as young adults, and it progressively declines as we age, step-in-step with our decreasing sleep.

However, selectively depriving people of Deep sleep does not always effect HGH levels. It appears that correlating deep sleep and health isas far as we can go – we still don’t have understand the direct causations of many relationships.

We’ve said it before, but it’s worth repeating: our understanding of sleep is still in its infancy.

The best way to insure healthy sleep is to track your symptoms as well as your sleep totals. At the end of the day – or the beginning of the day I should say — the most important thing to ask is how does it feel to wake up? Does sleep feel restorative?

From here, we can begin to make changes to our habits and priorities to get better rest at night and be more energetic during our days.

References:
Bes F., Schulz H., Navelet Y., Salzarulo P., “The distribution of slow-wave sleep across the night: a comparison for infants, children, and adults,” SLEEP. 1991 Feb; 14 (1): 5-12
Born J., Muth S., Fehm H.L., “The significance of sleep onset and slow wave sleep for nocturnal release of growth hormone (GH) and cortisol,” Psychoneuroendocrinology. 1998; 13 (3): 233-42
Espa F., Ondze B., Deglise P., Billiard M., Besset A., “Sleep architecture, slow wave activity, and sleep spindles in adult patterns with sleepwalking and sleep terrors,” Clinical Neurophysiology. 2000 May; 111 (5): 929-39
Lombardo P, Formicola G., Gori S., Gneri C., Massetani R., Murri L., Fagioli I., Salzarulo P., “Slow wave sleep (SWS) distribution across night sleep episode in the elderly,” Aging (Milano). 1998 Dec; 10 (6): 445-8
Mokhlesi B., Pannain S., Ghods F., Knutson K.L., “Predictors of slow-wave sleep in a clinic-based sample,” Journal of Sleep Research. 2011 Sep 28
Ondze B., Espa F., Dauvilliers Y., Billiard M., Besset A., “Sleep architecture, slow wave activity and sleep spindles in mind sleep disordered breathing,” Clinical Neurosphysiology. 2003 May; 114 (5): 867-74
Ratnavadivel R., Chau N., Stadler D., Yeo A., McEvory RD., Catcheside P.G., “Marked reduction in obstructive sleep apnea severity in slow wave sleep,” Journal of Clinical Medicine. 2009 Dec 15: 5 (6): 519-24
Van Cauter E., Leproult R., Plat L., “Age-related changes in slow wave sleep and REM sleep and relationship with growth hormones and cortisol levels in healthy men,” JAMA. 2000 Aug 16; 284 (7): 861-8

 

 

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