Sleep for heart health

Sleep is a fascinating phenomenon.

Virtually all animals, certainly all mammals, sleep. While the form and shape of sleep can vary, sleeping is a universal phenomenon. Even fish sleep, though their eyes remain open.

Sleep disorders like sleep apnea ("apnea" = without breathing) are growing in prevalence nationwide as the country gets fatter and fatter. Our throats assume a smaller diameter, even our tongues get obese. This results in intermittent obstruction to the airway during sleep, causing snoring. It also results in sleep interruption, particularly during attempts to "descend" down to the deepest phases of sleep. Dire health and cardiac consequences can sometimes emerge, such as high blood pressure, higher blood sugar, abnormal heart rhythms, impaired heart muscle function, even sudden death.

We are all familiar with the perceptible effects of sleep deprivation: edginess, crabbiness, diminished attention span, slowed reaction time. I'm not talking about sleep apnea or sleep disorders, but just simple duration of sleep. Data are emerging that both sleep deprivation and sleep excess may trigger undesirable changes in lipids (cholesterol values):

Associations of usual sleep duration with serum lipid and lipoprotein levels.

Kaneita Y, Uchiyama M et al.

STUDY OBJECTIVES: We examined the individual association between sleep duration and a high serum triglyceride, low HDL cholesterol, or high LDL cholesterol level. DESIGN AND SETTING: The present study analyzed data from the National Health and Nutrition Survey that was conducted in November 2003 by the Japanese Ministry of Health, Labour and Welfare. This survey was conducted on residents in the districts selected randomly from all over Japan. PARTICIPANTS: The subjects included in the statistical analysis were 1,666 men and 2,329 women aged 20 years or older. INTERVENTION: N/A. MEASUREMENTS AND RESULTS: Among women, both short and long sleep durations are associated with a high serum triglyceride level or a low HDL cholesterol level. Compared with women sleeping 6 to 7 h, the relative risk of a high triglyceride level among women sleeping <5 h was 1.51 (95% CI, 0.96-2.35), and among women sleeping > or =8 h was 1.45 (95% CI, 1.00-2.11); the relative risk of a low HDL cholesterol level among women sleeping <5 h was 5.85 (95% CI, 2.29-14.94), and among women sleeping > or =8 h was 4.27 (95% CI, 1.88-9.72). On the other hand, it was observed that the risk of a high LDL cholesterol level was lower among men sleeping > or =8 h. These analyses were adjusted for the following items: age, blood pressure, body mass index, plasma glucose level, smoking habit, alcohol consumption, dietary habits, psychological stress, and taking cholesterol-lowering medications. CONCLUSIONS: Usual sleep duration is closely associated with serum lipid and lipoprotein levels.

Triglycerides go up with too little or too much sleep. Note especially the extraordinary association of low HDL cholesterol with sleeping <5 hours (nearly 6-fold increased risk) or sleeping >8 hours (more than 4-fold increased risk).

Why do these effects develop? Does sleep deprivation, for instance, trigger higher adrenaline levels, encourage carbohydrate cravings or binges, make us less likely to engage in physical activity? Cortisol is elevated; could this be a factor? I know that I am a different person when sleep-deprived: irritable, less clear-thinking, quicker to anger, more critical, and I develop carbohydrate cravings. It's curious that triglycerides increase when sleep excess is present; what might that represent?

Anyway, the data are growing: Sleep is an important facet of health, both for maintaining a bright outlook and to discourage development of low HDL and high triglycerides. Though not specifically examined in this study, we know that low HDL/high triglycerides are, as a rule, associated with the undesirable small LDL particle pattern.

As a practical matter, you may also find sleep and waking from sleep more satisfying and restful if you sleep in increments of 90 minutes, e.g., 7 1/2 hours (rather than 7 or 8 hours). This is because the full cycle of sleep, from phase 1 to REM (rapid-eye movement sleep), requires 90 minutes for completion. That doped feeling that sometimes develops when awaking will disappear if you sleep according to your sleep cycle, which is usually 90 minutes long.

Comments (4) -

  • Anna

    6/8/2008 1:27:00 AM |

    Not to beat a dead horse, but sleep apnea is a often overlooked symptom of hypothyroidism, too.  

    One does not have to be overweight to have sleep apnea, either (& lack of  excess obesity may lead physicians to dismiss apnea as a diagnosis).  

    Untreated or undertreated hypothyroidism can result in weak muscles at the back of the throat (soft palate area) that close down during sleep.  

    For me, the sleep apnea presented as repeated violent nighttime coughing fits that would significantly disrupt my sleep (and my husband's).  Unfortunately, it was too easy to assume for too many years it was simply allergic post-nasal drip (doc was happy to Rx for that, of course, but nothing helped, nor did dusting Smile.

    A lot of weird, annoying breathing issues improved considerably once on a good dose of T4/T3 - excessive, uncontrollable yawning when reading aloud to my son (but strangely, not while talking), excessive sighing during the day (I was unaware, but my husband noticed it), etc.

  • Dr. William Davis

    6/8/2008 2:11:00 AM |

    What a fascinating insight!

    That's one I've never come across before.

  • Anonymous

    6/8/2008 12:06:00 PM |

    I'd like to file a complaint against the department of Mother Nature for creating excessive noise for the past 2 weeks.  This springs weather has been crazy in the mid-west with all the lightning, flooding, and tornado sirens.  Bring on the hot sticky summer weather, I'll get more sleep with it than I have with this excessively stormy spring.

    This week I was reminded that my brother in law does not sleep and that isn't an exaggeration.  The family is having a reunion this week and most are gathered at my folks house.  Instead of sleeping at night my brother in law just wonders around, gets on the computer, goes for a walk, etc.  About the only time I've seen him rest is when the TV is on.  He has what the hospital calls border line high blood pressure, 140 over something, I don't remember.  His cholesterol #s are not good also.  This is all in despite of being a marathon running, lifts weights, has little body fat.

    A month or so ago he began some parts of the TYP program.  Hopefully what he does will help.  His father had the same sleep problem and he passed away from a sudden heart attack in his mid50s.

  • Brin

    11/10/2012 3:39:52 AM |

    Hi all
    Just want to say that I am impressed by the information here. Also the friendliness of the posts. You are all working together for everyones benifits. Kudos!
    Since I was a very young child I have had insomnia, restless leg, migrains, anxiety. All of these things I have had since before starting school. All of these things, except the migrains did not have a name back then. I remember my mother coming in the morning to wake me, and i was still awake! I have also always had heart palpitations, always when I am at rest, never when I am exerting myself. Only in the last few years have "they" put names to these things. And only in the last few years have there been any information on help for same.
    A number of years ago i started Atkins, I have always been overweight. I am tall, Long fine bones, but always have had a "belly". Over time Atkins became for me Low -carb, I did not stay true to Atkins, I found low carb healthier and recipes for making delishis food is now all over the internet
    BUT always the issues of anxiety, insomnia, restless legs, migrains. I have always felt that they are all related. Of course my G.P. thinks I need to be on antidepresants .... which i was on for a number of years, then took myself off... thats a whole other story. But Because of the low carb diet a co worker lent me the wheat belly book... OMG!, then I found this blog. So now I am taking Vit. D, Magnesium, zinc, kelp,omega 3s, and about to start melitonin. Am stickin to the low carb forever, sans the wheat and grains. Am hopeing the next 57 yrs (thats how old I am ) will be healtier than the first.
    Thank you Dr. Davis, and everyone who contributes to the blog.