Sleep Is Good for Your Heart

What are you doing to prevent a heart attack? Perhaps you do the things cardiologists typically recommend: exercise, eat less saturated fat, take statins and omega-3 supplements. Now, there is another recommendation: get 6-9 hours high-quality sleep each night.

One recent report of over 400,000 people who were evaluated over seven years  revealed that people who slept 6-9 hours a night had a 20% lower risk of a heart attack than people who slept less. However, sleeping more than 9 hours had a 34% higher risk.

Napping also seems to be a good idea. A group in Switzerland just reported from 3,462  people that

Source: Unsplash.com

those who had two or more naps a week had significantly less cardiovascular disease than those who did not nap. The benefit was unrelated to the length of napping.

The reason sleep is beneficial has not been established, but two lines of reasoning could explain it. The heart gets a rest during sleep. Heart rate and blood pressure typically go down during sleep. Also, sleep gives us a break from the stressful events of the day, events which release hormones and activate the "fight or flight" system that put a strain on the heart.

As to the paradox of the harmful effects of too much sleep (> 9 hours), one possible cause is too much dreaming, which is tied to the amount of sleep. During dreaming, blood and heart rate can spike, depending on the nature of what one is dreaming about.  The incidence of unpleasant, and therefore stressful, dreams should increase with increasing amounts of sleep time. By the way, I published a theory that asserts that the purpose of dreaming is the brain’s way to tell itself it has had enough sleep and it is time to wake up.

Another cause of excessive sleep can be poor quality sleep. For example, insomniacs may need more sleep because they are not getting enough of good, restful sleep.

Sleep apnea is a proven cause of bad sleep. Apnea is extremely stressful and can raise blood pressure on a continual basis, even during wakeful hours.

So, sleep well, with pleasant dreams. If your dreams are disturbing, program your brain to stop that. Tell your brain its job is to nurture you, not beat up on you. See my Psychology Today post on "How Nightmares May Affect Us, and What We Can Do about It."

Sources:

Daghlas, I. et al. (2019). Sleep duration and myocardial infarction. J. Amer. College of Cardiology. 74, 1304-1314.

Häusler, N. et al. (2019). Association of napping in incident cardiovascular events in a prospective cohort study. Heart. doi: 10.1136iuheartjnl2019-314999 (Sept. 9)

Klemm, W. R. 2011. Why does REM sleep occur? A wake-up Hypothesis. Frontiers in Neuroscience. 5 (73): 1- 12. Doi: 10.3389/fnsys.2011.00073

Why Lucid Dreams Matter

Lucid dreams are often defined as the ones you know you are having in real time. These are the dreams where you seem to be conscious. You are aware of the story line, and you are often a central character in the story. Sometimes, you may even consciously manipulate the dream content toward a more acceptable outcome.

Scientists have recorded physiological changes during sleep, and there are multiple episodes during sleep, especially early in the morning, that display brain waves similar to those when you are awake accompanied by rapid, jerky eye moves (REM). When people were awakened every time these signs appeared, they invariably said a dream was interrupted.

Source, with permission: Carroll Jones III, Nathaniel Graphics, 2013

Incidentally, I have studied this in animals. It appears that REM sleep is an innate property of the brains of mammals. I discovered REM sleep in ruminants, which at the time were assumed to rest without true sleep. I also discovered a rudimentary form of REM sleep in armadillos, which I studied because they are among the most primitive mammals. However, only people show numerous REM episodes lasting significant times. I have even published a theoretical paper suggesting why people need so much REM sleep.

Some people claim that they don't have lucid dreams, but there are physiological indicators that everybody does dream. It is possible that lucid dreams can occur but are not consolidated in memory. What is the first thing you do when you wake up? You start thinking about something other than what you were dreaming about, such as going to the bathroom, your aching joints, having breakfast, upcoming day's events, and so on. Such distractions interfere with memory consolidation of recent thought.

A sleep-lab study in which the EEG was recorded revealed certain physiological signs that are unique to lucid dreams, as opposed to non-lucid dreams. Subjects were trained to generate, recognize, and remember lucid dreams. Subjects who commonly reported having lucid dreams were selected for specific training, which included reminding themselves before going to sleep that they were to recognize when they were having lucid dreams and signal that to sleep monitors by a specific pattern of eye movements (in dream sleep, only the eyes move continuously because a descending motor-inhibition circuit in the brainstem is activated). During early-morning sleep, when lucid dreams were more prevalent, EEG recordings during lucid dreaming revealed REM-like activity in frequency bands δ and θ, and higher-than-usual REM activity in the γ band, the between-states-difference peaking around 40 Hz. 

Voltage power in the 40 Hz band is strongest in the frontal and frontolateral region. Moreover, the 40-Hz activity during REM is more coherent with similar activity in other regions of the cortex. The specific increase in gamma activity and the increased in 40 Hz-band coherence in lucid dreaming suggests that these are this may be the physiological basic of consciousness.

This study is important because the EEG changes are not like those in regular, non-dream sleep but are similar to what occurs in conscious wakefulness. Thus, REM sleep seems to be a form of consciousness. The lucid dreams are special because the content means something, but usually expresses it symbolically or in metaphors. Your brain has escaped the editing shackles of wakefulness and is free to reveal things you might not know about. Sometimes it is things you don't want to know about. However, you brain is trying to tell you something. You don't have to be a Sigmund Freud to figure out some of the meaning.

With my own lucid dreams, when I reflect on the content, I often find they help me to recognize and deal with deeply personal issues. They can point the way to personal insight. If you reflect on the dream content right after awakening, you are likely to remember it. Lucid dream content can change your life, one small step at a time.

Sources:

Klemm, W. R. 2011. Why does REM sleep occur? A wake-up hypothesis. Frontiers in Neuroscience. 5 (73): 1- 12. Doi: 10.3389/fnsys.2011.00073

Voss, Ursula, Holzmann, Romain, Tuin, Inka, and Hobson, Allan, J. (2009). Lucid dreaming: A state of consciousness with features of both waking and non-lucid dreaming. Sleep. 32(9), 1191-1200. https://academic.oup.com/sleep/article/32/9/1191/2454513

Neuroscience research working for you

I just attended the 40th annual meeting of the Society for Neuroscience in San Diego. There were over 31,000 scientists there, about 20,000 of whom presented research findings.Attendees come from all over the world. I an a Charter member of the Society and attended the first and most of the other annual meetings. It is hard for "outsiders" to appreciate just how much has changed in brain research over that time. The first meeting had less than 1,000 attendees. Now the meeting is so big that only a handful of U.S. cities can host such a large meeting.

There were many papers on memory presented. Most, however, were focused on how the brain achieves memory, and a lot of that has no immediate practical application for everyday life. I keep an eye out for such papers and report them in this blog when I find it.

One paper confirmed what I already knew about teaching "old dogs new tricks."  It showed that learning of a series of items was impaired in Seniors compared to younger people, but the deficiency was overcome if the experimenters just increased the interval between presentation of items. In other words, you CAN teach old dogs new tricks, it just takes longer.

I was really excited to see that I am on the right track on my new book, due out from Springer next Spring. The book is titled "Atoms of Mind. The 'Ghost in the Machine' Materializes." A few scientists are starting to do  the kind of research I advocate in the book for the study of consciousness. While at the meeting, I got a new idea nobody has considered yet. I'll tell people about it in the book, which I am mailing off to the publisher in a week or so..

I presented a paper on why people dream. A commonly accepted idea is that we dream to consolidate memories of the preceding day's events  It is true that memory consolidation does occur in sleep, both dream and non-dream sleep. But that is not the CAUSE of either dreaming or non-dreaming sleep. It is the consequence.

The simple answer is that we dream because the brain becomes activated in what is called REM sleep. Activated brains want to think, and thinking during sleep is expressed as dreams. So the real question I addressed is why do we have REM sleep. It's a long story, but the short answer is that REM helps to re-boot a sleeping brain so that we can become awake and conscious again. My presentation was well received. I had 50 copies of handouts, and they were scarfed up in the first 30 minutes of my poster session. Lots of people left their e-mail address so I could mail them copies of the poster. Over 100 people came by the poster. And they weren't window shopping. They stayed, read it all, and discussed it with me during the time when I was attending the poster. Nobody could punch any holes in the theory. I think I have the best explanation anybody has every presented.

It has been a stimulating four days. I will need some time to unwind.