Is this just hype to generate headlines? Or is the truth buried in the enormous marketing clout of the medical device industry, among which the imaging device manufacturers reign supreme?

It’s been over 110 years since radiation was first used for medical imaging. Over those years, it has had its share of misadventures.

In the 1930s and 1940s, before the dangers of radiation were recognized, shoe shoppers had shoes fitted using an x-ray device of the foot to assess fit. High doses of radiation were used to shrink enlarged tonsils and extinguish overactive thyroid glands. Attitudes towards radiation were so lax that doctors commonly permitted themselves to be exposed without protection day after day, year after year, until an unexpected rise in blood cancers like leukemia was observed. As recently as the 1970s and 1980s, cancers like Hodgkins’ disease were treated with high doses of radiation, also leading to radiation-induced diseases decades later.

Not all radiation is bad. Radiation can also be used as a therapeutic tool and even today remains a useful and reasonably effective method to reduce the size, sometimes eliminate, certain types of cancer. Forty percent of people with cancer now receive some form of radiation as part of their treatment (Ron E 2003).


Just how much does medical radiation add to our exposure?

Estimates vary, but most experts estimate that medical imaging provides approximately 15% of total lifetime exposure. In other words, radiation exposure from medical imaging is simply a small portion of total exposure that develops over the years of life. Exposure can be much higher, however, in a specific individual who undergoes repeated radiation imaging or treatment of one sort or another.

For all of us, exposure to medical radiation is part of lifetime exposure from multiple sources, added to the radiation we receive from the world around us. Just by living on earth, we are exposed to radiation from space and naturally-occurring radioactive compounds, and receive somewhere around 3.0 mSv per year (U.S. Nuclear Regulatory Commission). (Doses for radiation exposure are commonly expressed in milliSieverts, mSv, a measure that reflects whole-body radiation exposure.) People living in high-altitude locales like Colorado get exposed to an additional 30–50% ambient radiation (1.0–1.5 mSv more per year).

Much of the information on radiation exposure comes from studies like the Life Span Study that, since 1961, has tracked 120,000 Japanese exposed to radiation from the atomic bombs dropped in 1945 (Preston DL et al 2003). Although regarded as a high-dose exposure study for obvious reasons, there are actually thousands of people in this study who were exposed to lesser quantities of radiation (because of distance from the bomb sites) who still display a “dose-response” increased risk for cancer many years later in life. Radiation exposures of as little as 5–20 mSv showed a slight increase in lifetime risk.

Occupational and excessive medical exposure to radiation also provides a “laboratory” to examine radiation risk. Miners exposed to radon gas; patients exposed to the imaging agent, Thorotrast, containing radioactive isotope thorium dioxide and used as an x-ray contrast agent in the 1930s and 1940s and possesses the curious property of lingering in the body for over 30 years after administration; radium injections administered between 1945 and 1955 to treat diseases like ankylosing spondylitis and tuberculosis, all provide researchers an opportunity to study the long-term effects of various types of radiation exposure over many years (Harrison JD et al 2003).

The excess exposure of workers and several hundred thousand nearby residents to the Mayak nuclear plant in Russia has also revealed a “dose-response” relationship, with increasing exposure leading to more cancers, including leukemia and solid cancers of the bone, liver, and lung (Shilnikova NS et al 2003). Nuclear waste released into the Techa river between 1948 and 1956 contaminated drinking water used by over 100,000 Russians. A plant explosion in 1957 also released an excess of radiation into the atmosphere, yielding exposure via inhalation. Some sources estimate that at least 272,000 people have been affected by radiation from the Mayak plant. This unfortunate situation has, however, yielded plenty of data on radiation exposure and its long-term effects.

It’s also been known for several decades that people who receive therapeutic radiation for treatment of cancer, even with the reduced doses now employed, are subject to increased risk of a second cancer consequent to the radiation treatment.

From experiences like this, radiation experts estimate that an exposure of 10 mSv increases a population’s risk for cancer by 1 in 1000 (Semelka RC et al 2007).

This question was recently thrust into the spotlight with publication of a study from Columbia University in New York suggesting that a 20-year old woman would be exposed to a lifetime risk of cancer as high as 1 in 143 consequent to the radiation received during a CT coronary angiogram. (Important note: This was estimated risk from a CT coronary angiogram, not a simple heart scan that we advocate for the Track Your Plaque program.) The risk at the low end of the spectrum would be in an 80-year old man (because of the shorter period of time to develop cancer), with a risk of 1 in 5017. If “gating” to the EKG is added (which many scan centers do indeed perform nowadays), risk for a 60-year old woman is estimated at 1 in 715; risk for a 60-year old male, 1 in 1911 (Einstein AJ et al 2007). This study generated some criticism, since it did not directly involve human subjects, but used “phantoms” or x-ray dummies to simulate x-ray exposure. Nonetheless, the point was made: CT coronary angiograms in current practice do indeed expose the patient to substantial quantities of radiation, sufficient to pose a lifetime risk of cancer.


The media frenzy

The NY Times ran an article called With Rise in Radiation Exposure, Experts Urge Caution on Tests in which they stated:

"According to a new study, the per-capita dose of ionizing radiation from clinical imaging exams in the United States increased almost 600 percent from 1980 to 2006. In the past, natural background radiation was the leading source of human exposure; that has been displaced by diagnostic imaging procedures, the authors said."

“This is an absolutely sentinel event, a wake-up call,” said Dr. Fred A. Mettler Jr., principal investigator for the study, by the National Council on Radiation Protection. “Medical exposure now dwarfs that of all other sources.”

Radiation is a widely used imaging tool in medicine. Although CT scans of the brain, bones, chest, abdomen, and pelvis account for only 5% of all medical radiation procedures, they are responsible for nearly 50% of medical radiation used. It’s been known for years that increasing radiation exposure increases cancer risk over many years, but the boom of newer, faster devices that provide more detailed images has opened the floodgates to expanded use of CT scanners.

But before we join in the hysteria, let's first take a look at exposure measured for different sorts of tests:

Typical effective radiation dose values for common tests

Computed Tomography

Head CT 1 – 2 mSv
Pelvis CT 3 – 4 mSv
Chest CT 5 – 7 mSv
Abdomen CT 5 – 7 mSv
Abdomen/pelvis CT 8 – 11 mSv
Coronary CT angiography 5 – 12 mSv


Non-CT

Hand radiograph Less than 0.1 mSv
Chest radiograph Less than 0.1 mSv
Mammogram 0.3 – 0.6 mSv
Barium enema exam 3 – 6 mSv
Coronary angiogram 5 – 10 mSv
Sestamibi myocardial perfusion (per injection) 6 – 9 mSv
Thallium myocardial perfusion (per injection) 26 – 35 mSv

Source: Cynthia H. McCullough, Ph.D., Mayo Clinic, Rochester, MN


A plain, everyday chest x-ray, providing less than 0.1 mSv exposure, provides about the same quantity of radiation exposure as flying in an airplane for four hours, or the same amount of radiation from exposure to our surroundings for 11–12 days. Similar exposure arises from dental x-rays.

If you have a heart scan on an EBT device, then your exposure is 0.5-0.6 mSv, roughly the same as a mammogram or several standard chest x-rays.

With a heart scan on a 16- or 64-slice multidetector device, exposure is ideally around 1.0-2.0 mSv, about the same as 2-3 mammograms, though dose can vary with this technology depending on how it is performed (gated to the EKG, device settings, etc.)

CT coronary angiography presents a different story. This is where radiation really escalates and puts the radiation exposure issue in the spotlight. As Dr. Cynthia McCullough's chart shows above, the radiation exposure with CT coronary angiograms is 5-12 mSv, the equivalent of 100 or more chest x-rays or 20 mammograms. Now, that's a problem.

The exposure is about the same for a pelvic or abdominal CT. The problem is that some centers are using CT coronary angiograms as screening procedures and even advocating their use annually. This is where the alarm needs to be sounded. These tests, as wonderful as the information and image quality can be, are not screening tests. Just like a pelvic CT, they are diagnostic tests done for legitimate medical questions. They are not screening tests to be applied broadly and used year after year.

It’s also worth giving second thought to any full body scan you might be considering. These screening studies include scans of the chest, abdomen, and pelvis. These scans, performed for screening, expose the recipient to approximately 10 mSv of radiation (Radiological Society of North American, 2007). Debate continues on whether the radiation exposure is justified, given the generally asymptomatic people who generally undergo these tests.

Always be mindful of your radiation exposure, as the NY Times article rightly advises. However, don't be so frightened that you are kept from obtaining truly useful information from, for instance, a CT heart scan (not angiography) at a modest radiation cost.


Heart scans, CT coronary angiograms and the future

Unfortunately, practicing physicians and those involved in providing CT scans are generally unconcerned with radiation exposure. The major

The world according to the Wheat Foods Council and the Whole Grains Council

23. abril 2010 William Davis (26)

You might get a kick out of what the Wheat Foods Council and the Whole Grains Council recommend for a sample meal plan:

Breakfast: Whole grain raisin toast

Lunch: Sandwich on whole grain
Snack: Rye bread crackers
Dinner: Whole grain pasta with your favorite sauce

Breakfast: Whole grain waffles 

The ultimate “bioidentical” hormone

2. July 2009 William Davis (19)

There has been a lot of debate over whether or not “bio-identical” hormones, i.e., hormones identical to the human form, are superior to non-human forms dispensed by the drug industry.

The FDA is currently taking steps to clamp down on availability of bioidentical hormones and their claims of superiority, despite a groundswell of grassroot support for them. The argument has pitted anti-aging practitioners and the public, as well as the likes of Oprah and Suzanne Somers, against Big Pharma and the FDA, the two forces trying to squash the bioidentical hormone movement.

Regardless of what heavy-handed approach the FDA takes, we already have access to hormones identical to the original human form. It requires no prescription and yields downstream hormones that the human body recognizes as human.

That "bioidentical" hormone is pregnenolone.

Pregnenolone is the first biochemical step in the conversion of dietary cholesterol (yes-cholesterol!) to numerous other hormones. Pregnenolone is the source of the hormones that lie at the center of the bioidentical hormone controversy: estrogens, progesterone, and testosterone. We therefore already have our own over-the-counter, non-prescription form of bioidentical hormones.

Supplemental pregnenolone increases estrogens (mildly), progesterone, and testosterone. Prenenonlone supplementation simply provide more of the basic substrate for hormone production. The increase in hormones is usually modest, not as vigorous as direct hormone replacement like, say, testosterone or progesterone topical creams. But pregnenolone can be useful when small to moderate increases are desired, such as for reduction of Lp(a). A theoretical downside is that pregnenonlone can also convert to cortisol, the adrenal gland hormone that regulates fluid and blood pressure. However, I've not seen any measurable increase in cortisol with low doses of pregnenonlone and limited data suggest that it does not. Pregnenolone also converts to the other adrenal gland hormone, DHEA; I call DHEA "the hormone of assertiveness," since some people who take too much pregnenolone (or direct DHEA) acquire excessive assertiveness.

The key to pregnenolone supplementation is to proceed gradually and begin with a small dose, e.g., 5 mg every morning. Hormonal assessment is best conducted periodically to assess the effects and to determine whether a dose adjustment is in order.

Roger's near-miss CT angiogram experience

27. June 2009 William Davis (13)

Heart Scan Blog reader, Roger, described his near-miss experience with CT coronary angiograms.

Hoping to obtain just a simple CT heart scan, he was bullied to get a CT coronary angiogram instead. Roger held strong and just asked for the test that we all should be having, a CT heart scan.


I posted yesterday that I was about to have my first CT heart scan...well, it was an interesting experience for reasons I coudn't possibly have anticipated. Dr. Davis has commented in the past on the confusion in the media about the difference between a CT calcium score scan, and a CT angiography, the latter requiring a far higher dose of radiation. I assumed this was a source of confusion only among patients and lay folks, but, lo and behold, I discovered today that doctors--or at least their helpers--can be just as confused.

Here's my story:

After checking in, I asked the receptionist to see if she had any information on whether my medical insurance was covering the scan. She called someone, and I heard her say over the phone, "He's here for a CT angiogram." At that point my ears perked up. I explained I wasn't here for a CT angiogram, only a regular CT scan. "Well, do you want to call your doctor and talk about this?" she asked. No, I said, I would like to ask one of their folks to verify exactly what test my doctor had ordered. As luck would have it, the technician was walking by at that point. "Is this a CT angiogram?" the receptionist asked. "No, it's just a CT calcium score scan" was the reply. But apparently the technician had been unclear herself, and had called my doctor just to verify. In other words, the "default" procedure they were accustomed to doing at this august Houston vascular clinic was a CT angiogram.

In fact, my appointment was even listed on their calendar as a "CT angiogram." For all I know, my insurance will be billed for the same. Later, during the procedure, the technician acted surprised I wasn't doing the "full test." I explained I had minimal risk factors (actually only one, an HDL of 34 a couple of years ago, which has since been raised to 50 partly as a result of taking advice from this site), but that my doctor was progressive (he is an MD for the Houston Astros) and thought it was a good idea since there is heart disease in my immediate family. My doctor did indeed prescribe only a CT calcium score scan, but it seems to have been an order that this clinic, at least, wasn't all that used to seeing.

So, I guess the message is: we have a lot of educating to do. Had I not been a faithful reader of these pages, I certainly wouldn't have known what kind of test I was about to get, or what questions to ask!

As for the heart scan itself, a piece of cake. If you can hold your breath, you can take this test. Just be sure it is the right one!


Why the "push" towards CT coronary angiograms and not "just" a CT heart scan? Well, I know it's shocking but it's . . . money!

CT coronary angiograms yield around $1800-$4000 per test. CT heart scans yield somewhere around $200. Though the scan center support staff might not care too much about the money themselves, their administrators likely make the cost distinctions clear to them.

Another reason: Most scan center staff, ironically, don't understand what a heart scan means, nor do they understand how it might serve to launch a program of prevention. They do understand that severe blockage by CT angiogram "needs" to be stented or bypassed. So they push patients towards things they understand.

Nobody makes money from CT heart scans, just as nobody makes money from a mammogram. Heart scans also don't lead to heroic, "lifesaving" procedures. They just lead to this sleepy, unexciting, inexpensive thing called prevention.

The Myth of Prevention: Letter to the Wall Street Journal

25. June 2009 William Davis (20)

The June 20-21, 2009 Wall Street Journal Weekend Journal featured a provocative front page article written by physician, Dr. Abraham Verghese:

The Myth of Prevention

While eloquently written, I took issue with a few crucial points. Here is the letter I sent to the Editor at Wall Street Journal:


Dear Wall Street Journal Editor,

Re: Dr. Abraham Verghese’s article, The Myth of Prevention in the June 20-21, 2009 Weekend Journal.


I believe a more suitable title for Dr. Verghese’s article would be: “The Myth of What Passes as Prevention.”

As a practicing cardiologist, I, too, have witnessed firsthand the systemic “corruption” described by Dr. Verghese, the doing things “to” people rather than “for” them. Heart care, in particular, is rife with this form of profit-driven health delivery.

There is a fundamental flaw in Dr. Verghese’s otherwise admirable analysis: He assumes that what is called “prevention” in mainstream medicine is truly preventive.

Dr. Verghese makes issue of the apparent minor differences between preventing a condition and just allowing a condition to run its course. Prostate cancer screening is one example: Men subjected to repeated screenings have little length-of-life advantage over men who just allow their prostate to suffer the expected course of disease.

What if, instead, “prevention” as practiced today is nothing more than a solution that has been adopted in mainstream practice to suit yet another doing “to” strategy than doing “for”? In the prostate cancer example, PSA and prostate exam screenings often serve as little more than a means of harvesting procedures for the local urologist.

That’s not prevention. It is a prototypical example of “prevention” being subverted into the cause of revenue-generating procedures.

I submit that Dr. Verghese has fallen victim to the very same system he criticizes. His views have unwittingly been corrupted by the corrupt profit-driven system he describes.

What if, instead, prevention were just that: prevention or elimination of the condition. What if “prevention” of prostate cancer eliminated prostate cancer? What if heart disease “prevention” prevented all heart disease? What if this all proceeded without regard for profit or revenue-generating procedures, but just on results?

Dr. Verghese specifically targets heart scans or coronary calcium scoring, a test he likens to “miracle glow-in-the-dark minnow lures,” calling them “moneymakers.” Yes, when subverted into a corrupt algorithm of stress test, heart catheterization, stent, or bypass, heart scans are indeed a test used wrongly to “prevent” heart disease.

But what if the risk insights provided by heart scans prompt the start of a benign yet effective “prevention” program that inexpensively, safely, and assuredly prevents--in the true sense of the word--or eliminates heart disease? Then I believe the differences in mortality, quality of life, and costs would be substantial. Such strategies exist, yet do not necessarily include prescription drugs and certainly do not include the aftermath of heart catheterization and bypass surgery. Yet such programs fail to seize the limelight of media attention with no new high-tech lifesaving headline nor a big marketing budget to broadcast its message.

The problem in medicine is not prevention and its failure to yield cost- and life-saving results. It is the pervasively profit-driven mindset that keeps true preventive strategies from entering mainstream conversation. It is a repeat of Dr. Ignaz Semmelweis’ late 19th-century pleads for physicians to wash their hands before delivering babies to reduce puerperal sepsis, ignominious advice that earned him life and death in an asylum. We are essentially continuing to deliver children with unwashed hands because there is no revenue-generating procedure to clean them.

No, Dr. Verghese, the economic and medical failings of preventive strategies are not at fault. The failure of the medical system, in which everyone is bent on seizing a piece of the financial action for himself, has resulted in the failure to support the propagation of true preventive strategies that could genuinely save money and lives.

President Obama’s goal of cultivating preventive practices in medicine can work, but only if the profit-motive for “prevention” does not serve as the primary determinant of practice. Results-driven practices that are applied without regard to profit have the potential to yield the sorts of cost-saving and life-saving results that can reduce healthcare costs.


William Davis, MD
Milwaukee, Wisconsin
Medical Director, The Track Your Plaque Program (www.cureality.com)
Blog: http://heartscanblog.blogspot.com

A victory for SHAPE, CT heart scans, and doing what is RIGHT

24. June 2009 William Davis (7)

The efforts of Texas House of Representatives Rep. Rene Oliveira and the SHAPE Guidelines committee have paid off: The Texas legislature passed a bill that requires health insurers to cover CT heart scans.

(NOTE: Don't make the same mistake that the media often makes and confuse CT heart scans with CT coronary angiography: two different tests, two different results, two different levels of radiation exposure. The difference is discussed here.)

Track Your Plaque previously reported the release of the SHAPE Guidelines, an ambitious effort to open CT heart scanning to people who would benefit from a simple screening test for coronary disease. Rep. Rene Oliveira initially introduced the bill in 2006, after having a heart scan uncovered extensive coronary plaque that resulted in coronary bypass surgery.

The bill requires that health-benefit providers cover the cost of CT heart scans (and carotid ultrasound) in men between the ages of 45-76, women 55-76, as well as anyone with diabetes or at "intermediate-risk" or higher for coronary disease by Framingham risk score.

The usual panel of cardiology knuckleheads stepped to the media podium, expressing their incredulity that something as "unvalidated" as heart scans could gain the backing of legislative mandate. Heartwire carried this comment:

"Contacted by heartwire, Dr Amit Khera (University of Texas Southwestern Medical Center, Dallas) confirmed there are still no comprehensive, adequately powered studies showing that these screening tests lead to better outcomes. In a phone interview, Khera said he has major concerns about how physicians will use these tests, particularly primary-care physicians. "I gave a talk last week to primary-care doctors, and there were probably 250 people in the room, and when I asked how many people had ordered a calcium scan, just one person raised a hand. . . . Most people don't even know what to do with the Framingham risk score, so they're going to follow an algorithm that they don't know how to follow to order a test result that they don't know what to do with."

It's the same criticisms hurled at heart scans over the years despite literally thousands of studies validating their application.

Studies have conclusively shown that:

--Coronary calcium scores generated by a CT heart scan outperform any other risk measure for coronary disease, including LDL cholesterol, c-reactive protein, total cholesterol, HDL cholesterol, blood pressure.
--Coronary calcium scores yield a graded, trackable index of coronary risk. Scores that increase correlate with increased risk of cardiovascular events; scores that remain unchanged correlate with much reduced risk.
--A coronary calcium score of zero--no detectable calcium--correlates with extremely low 5-year risk for cardiovascular events.
--Coronary calcium scores correlate with other measures of coronary disease. Heart scans correlate with coronary angiography, quantitative coronary angiography, carotid ultrasound (intimal-medial thickness and plaque severity), ankle-brachial index, and stress tests, including radionuclide (nuclear) perfusion imaging.

The reluctance of my colleagues to embrace heart scans stems from two issues, for the most part:

1) No study has yet been performed showing that knowing what the score is vs. not knowing what the score is changes prognosis. That's true. But it is also true of the great majority of practices in medicine. While many wrongs don't make a right, the miserable and widespread failure of other coronary risk measures, like LDL cholesterol or c-reactive protein, to readily and reliably detect hidden coronary disease creates a gaping void for improved efforts at early detection. If your LDL cholesterol is 140 mg/dl, do you or don't you have coronary disease? If your doctor's response is "Just take a statin drug anyway" you've been done a great disservice. (If and when this sort of study gets done, its huge cost--outcome studies have to be large and last many years--it will likely be a statin study. It is unlikely it will include such Track Your Plaque strategies that help reduce heart scan scores, like vitamin D and correction of small LDL particles.)

2) Fears over overuse of hospital procedures triggered by heart scans. This is a legitimate concern--if the information provided by a heart scan is misused. Heart scans should never--NEVER--lead directly to heart catheterization, stents, bypass surgery. Heart scans do not change the indications for performing revascularization (angioplasty, stents, bypass). Just because 20% of my cardiology colleagues are more concerned with profit rather than patient welfare does not invalidate the value of the test. Just because the mechanic at the local garage gouged you by replacing a carburetor for $800 when all you need was a new spark plug does not mean that we should outlaw all auto mechanics. Abuse is the fault of the abuser, not of the tool used to exercise the abuse.


All in all, while I am not a fan of legislating behavior in healthcare, the blatant and extreme ignorance of this simple tool for uncovering hidden heart disease makes the Texas action a huge success for heart disease prevention. I hope that this success will raise awareness, not just in Texas, but in other states and cities in which similar systemic neglect is the rule.

Remember: CT heart scans are tools for prevention, not to uncover "need" for procedures. They serve as a starting point to decide whether or not an intensive program of prevention is in order, and I don't mean statin vs. no statin.

Though not a multi-million dollar statin drug study, I have NEVER seen a heart attack or "need" for procedure in any person who has stopped progression or reduced their heart scan score. A small cohort from my practice was reported:

Effect of a Combined Therapeutic Approach of Intensive Lipid Management, Omega-3 Fatty Acid Supplementation, and Increased Serum 25 (OH) Vitamin D on Coronary Calcium Scores in Asymptomatic Adults.

Davis W, Rockway S, Kwasny M.

The impact of intensive lipid management, omega-3 fatty acid, and vitamin D3 supplementation on atherosclerotic plaque was assessed through serial computed tomography coronary calcium scoring (CCS). Low-density lipoprotein cholesterol reduction with statin therapy has not been shown to reduce or slow progression of serial CCS in several recent studies, casting doubt on the usefulness of this approach for tracking atherosclerotic progression. In an open-label study, 45 male and female subjects with CCS of >/= 50 without symptoms of heart disease were treated with statin therapy, niacin, and omega-3 fatty acid supplementation to achieve low-density lipoprotein cholesterol and triglycerides /=60 mg/dL; and vitamin D3 supplementation to achieve serum levels of >/=50 ng/mL 25(OH) vitamin D, in addition to diet advice. Lipid profiles of subjects were significantly changed as follows: total cholesterol -24%, low-density lipoprotein -41%; triglycerides -42%, high-density lipoprotein +19%, and mean serum 25(OH) vitamin D levels +83%. After a mean of 18 months, 20 subjects experienced decrease in CCS with mean change of -14.5% (range 0% to -64%); 22 subjects experienced no change or slow annual rate of CCS increase of +12% (range 1%-29%). Only 3 subjects experienced annual CCS progression exceeding 29% (44%-71%). Despite wide variation in response, substantial reduction of CCS was achieved in 44% of subjects and slowed plaque growth in 49% of the subjects applying a broad treatment program.

Sleep: A to Zzzzzzzzzz

23. June 2009 William Davis (5)

Take a look at the results from the Heart Scan Blog's most recent reader poll (399 respondents):

How many hours do you sleep per night (on average)?


9 or more hours per night
15 (3.7%)

8-9 hours per night
72 (18%)

7-8 hours per night
152 (38.1%)

6-7 hours per night
111 (27.8%)

5-6 hours per night
38 (9.5%)

Less than 5 hours per night
11 (2.8%)


Like many issues in health, too much or too little of a good thing can present undesirable consequences.

Too much sleep: While psychologists and sleep researchers advise us that at least 9 hours are required to fully eliminate sleep "debt" and achieve optimal vigilance and mental performance, epidemiologic studies have shown increased mortality with this quantity of sleep.

Too little sleep: Getting less than 7 hours habituallly increases blood sugar, appetite, inflammatory measures, and encourages weight gain. Mortality is also increased, just as with sleeping too much. It is also associated with increased likelihood of a positive heart scan score.

7-8 hours per night from a health viewpoint is that Goldlilocks "just right" value: just enough to not erode mental performance substantially, but not so little that inflammatory, insulin-disrupting, and appetite-increasing effects develop.

Of our 399 respondents in the poll, 56.1% (38% + 18%) slept what appears to be an optimal amount for health. While only 3.7% slept too much (9 hours or more), the remaining 40.1% slept too little.

Our informal poll confirms what most of us observe in everyday life: The majority of people shortchange sleep in order to meet the demands of their high-pressure, squeeze-as-much-as-possible-into-every-day lives. But not paying off your sleep "debt" is like not paying the mortgage for a couple of months. You wouldn't expect your friendly neighborhood bank to say, "Oh, you forgot to pay your mortgage? Forget about it. Just pay next month's." Sure, fat chance. But if you don't pay off your sleep "debt," you will pay it back with health.

<< Older posts Newer posts >>

• Newer posts
• 1
• 2
• ...
• 39
• 40
• 41
• 42
• 43
• 44
• 45
• 46
• 47
• ...
• 123
• 124
• Older posts