do we really only sleep in 90 minute cycles?

Answer 1

Roughly, it varies slightly from person to person. I find planning my sleep schedule on this is helpful as it's much easier to wake up out of REM sleep as opposed to deep sleep.

Answer 2

No, that is a simplification.

your brain has three different clock systems running within it.

the oldest part, the reptilian brain at the base of the neck, works on a 28 hour clock, reset at sunrise. It controls most body functions

the middle is the mamalian brain, and is on a 28 day cycle, controled by luna gravity. it overides the reprtilian brain, and allows us to use the chemical energy of stomach, rather than sunlight to control our body temprature. The body clock of the older brain controls sleep via body temprature.

Rem sleep is when the brain repairs cells, thus memories. Deep sleep is where the body is repaired. however we all have grey matter, a cranium, that is 80% of the mass, and it makes us individual. some folks slip into sleep easily, others will take far longer to get into sleep patterns, so the 90 minute cycle is in reality as much as 110 minutes for some folks, and 80 minutes for others.

Some research suggests that there are variations within these stages according to the individual and that these differences may vary again within an individual from night to night. These patterns may be affected by a person’s mental state (Rickards). Sleep disorders may be the primary presenting problem or they may be a response to something else such as an anxiety disorder or depression

Some folks suffer from sleep starts - sudden jerks, which occur at the beginning of sleep and can be considered normal as it affect 60-70% of the population. ‘Severe increased exertion’, emotional stress and too much caffeine can increase the frequency of sleep starts. These movements can involve the arms or the legs or the whole body and there might also be feelings of falling or imbalance (newcastle).

Answer 3

On average that's about right but it can be between 90 and 120 minute cycles. This is governed by our biological rhythms and continues through our waking period of the day. The acronym BRAC,which stands for Basic Rest Activity Cycle governs our life 24 hours a day, and during our waking life we routinely follow patterns of activity and rest which are also between 90 and 120 minutes duration.
A good book on this subject is by Ernest Lawrence Rossi, 'The 20 minute break', Ultradian Healing Response.

Answer 4

Yes, so says my Psychology teacher.

Answer 5

yes

Answer 6

yes

Answer 7

It's what I've heard, but that's not specific. I want to see someone in R.E.M.!!!

Answer 8

sure why not if you say so