Wednesday, March 31, 2010
"My three hypotheses all remain viable:
Weak form: Chronic Steady state aerobic training* (CSSAT) does nothing to prevent or reverse atherosclerosis.
Mild Form: Some effects of CSSAT may be beneficial or neutral, but they are overridden by the inflammation promoting effects of the diets favored by those who train this way.
Strong Form: CSSAT itself promotes the inflammatory state via cortisol, cytokines, inadequate recovery, etc."
This lady offers a great angle on sugar. While I would not agree with all of her ideas about nutrition, if I were stuck in a sugar addicition, I might seek out her aid. She's certainly persuasive that sugar holds a special place in the pantheon of dangerous foods - which is why Dr. Davis' advice to eliminate sugar and wheat seems very, very smart, as does CrossFit Prescription: "Eat meat and vegatable, nuts and seeds, some fruit little starch and no sugar."
Tuesday, March 30, 2010
In "2005, there was a report in the medical journal Neurology. It described a pilot study of a special diet for the management of Parkinson's Disease. The whole trial only lasted 28 days and only involved seven people, of whom only five completed the full month. In these five there was an improvement in their Parkinson's disease. Keep in mind Parkinson's is supposed to be irreversible... By the way, a small trial like this is VERY significant. If you have a therapy which makes a big difference it will show in a small trial. If your trial needs 100,000 people to show a minor benefit, the benefit for an isolated individual will clearly be pretty well undetectable. That's interesting in its own right. But much more interesting was the interview with one of the participants published in USA Today. The article tells us what she ate and mentions that she lost 26lb. The study lasted 28 days. That is an impressive weight loss. So what sort of a diet combines modest reversal of an irreversible disease with dramatic weight loss? The diet is what is known as a ketogenic diet. Just a little meat or eggs each day, plus lots and lots of fat. No carbohydrate. Under these conditions the liver manufactures large quantities of ketone bodies, which are an excellent fuel for the brain and easily able to replace at least half of the daily glucose which is usually considered "essential". It appears that if you feed dopaminergic brain cells on ketone bodies they stop dying, and maybe the sick-but-not-yet-dead ones recover. The brain likes ketone bodies. Why did the weight loss happen? It is self evident that eating fat makes you fat. Just ask any dietician. It's obvious. Very obvious. But not true. Ketogenic diets are excellent for weight loss. The physiology is logical and unimportant here, but minimal carbohydrate intake is essential for it to work." One concept of the Paleolithic model is that our ancestors went through long periods of ketogenesis - fall and winter, at least, and perhaps most nights and mornings. If so, they were gaining the benefits of a ketone fueled brain routinely. This is at least a good match between that model and the observation that aboriginals eating their traditional diets have not been observed with Parkinson's/Alzheimers etc.
Monday, March 29, 2010
AGEs are part of aging; they are part of human disease. AGEs are the result of modification of proteins by glucose. AGEs form the basis for many disease conditions.
Accumulated AGEs have been associated with aging, dementia, cataracts, osteoporosis, deafness, cancer, and atherosclerosis. Most of the complications of diabetes have been attributable to AGEs.
There's one readily available method to assess your recent AGE status: HbA1c.
Hemoglobin is the oxygen-carrying protein of red blood cells. Like other proteins, hemoglobin becomes glycated in the presence of glucose. Hemoglobin glycation increases linearly with glucose: The higher the serum or tissue glucose level, the more glycation of hemoglobin develops. Glycated hemoglobin is available as the common test, HbA1c.
Ideal HbA1c is 4.5% or less, i.e., 4.5% of hemoglobin molecules are glycated. Diabetics typically have HbA1c 7.0% or greater, not uncommonly greater than 10%.
In other words, repetitive and sustained high blood glucose leads to greater hemoglobin glycation, higher HbA1c, and indicates greater glycation of proteins in nerve cells, the lens of your eye, proteins lining arteries, and apoprotein B in LDL cholesterol particles."
Sunday, March 28, 2010
Well, no. With this extrapolation, scientists and policymakers made a grave miscalculation: They assumed that all LDL cholesterol is the same and that all of it is bad. A spate of recent research is now overturning this fallacy and raising major questions about the wisdom of avoiding fat, especially considering that the food Americans have been replacing fat with—processed carbohydrates—could be far worse for heart health."
"In a 2000 study in the American Journal of Clinical Nutrition,Harvard researchers compared the food intakes of 75,521 women with their health over the course of a decade and found that the quintile of women who ate food with the highest glycemic load—a measure that incorporates portion size—had twice the risk of developing heart disease than the quintile who ate food with the lowest glycemic load. A 2008 meta-analysis of 37 studies reported a significant association between intake of high glycemic index foods and increased risk of type 2 diabetes, heart disease, gallbladder disease, and breast cancer."
"In a 2008 study published in Nutrition Research, researchers reported that subjects who followed high-fat, low-carb diets for eight weeks experienced a 46 percent drop in blood concentrations of small LDL particles, while those who followed a high-carb, low-fat diet experienced a 36 percent spike in them. What's more, processed carbohydrates lower "good" HDL cholesterol, whereas saturated fat increases it."
"Research published by Peter Havel, a professor of nutrition at the University of California-Davis, suggests that compared with glucose, fructose incites less of an insulin response, which ultimately results in lower circulating levels of the appetite-suppressing hormone leptin and higher levels of the appetite-boosting hormone ghrelin—so fructose may make you hungrier.
"It could also put you at greater risk of heart disease and diabetes. When overweight people supplemented their diets with drinks sweetened either with fructose or with glucose for 10 weeks, fructose drinkers ended up with higher concentrations of small LDL particles in their blood after they ate. They also experienced, on average, a 20 percent drop in insulin sensitivity—low insulin sensitivity is a risk factor for type 2 diabetes—over the course of the experiment compared with the glucose drinkers."
"As far as I can see AD, PD and ALS are all essentially the same disease, but the genetics of your glutamate receptor subtypes or quirks of your glutamate processing enzymes determine which you get. They're excitotoxin diseases, and Russell Blaylock has the most self consistent hypothesis of their generation that I've come across. According to Blaylock the glutamate neurotransmitter receptor sporting cells can be driven to a catastrophic energy failure under certain conditions. Adding ketones as an alternative to glucose appears to supply energy to allow both survival and improved function of neurones which are doing very badly on glucose.
Having read Vanitallie's abstract and Marilyn Deaton's account of eating an extreme ketogenic diet, I'd imagined that we would be needing ketones ++++++, ie. off the top of the scale, as for the rather problematic ketogenic epilepsy diet (especially if designed by a cholesterophobic nutritionist. But Dr Mary Newport got a detectable effect within 24 hours from 40ml, or 350kcal, of coconut oil. Without carbohydrate restriction. That's pretty impressive.
So the neuroprotection appears to kick in at very low levels of ketones. It might not even be necessary to go to Atkins induction. Something as mildly ketogenic as the Optimal Diet might just do the job.
(Commenting on another study about diabetic rat appetite on a high fat diet): Look at the calorie intake of the diabetic rats! For normal rats diet composition made no difference to food intake. For diabetic rats (streptozotocin induced) see how appetite skyrocketed on low fat but virtually normalised with increasing fat content (any fat) by the time fat got up to 25% of calories. The lower the fat content, the more hyperphagic (read HUNGRY) the rats became, the fatter they became too.
It just reminded me of the cruelty of telling human diabetics to eat a low fat, high carbohydrate diet and then berating them for their gross gluttony. "
Saturday, March 27, 2010
Would you be kind enough to review, and post your thoughts to comments below? I am working on a series of articles about this book, and it would be very helpful for me to know what thoughts and questions and observations my audience has in reviewing this summary. Thanks for your help!
1. Dietary fat, whether saturated or not, is not a cause of obesity, heart disease, or any other chronic disease of civilization.
2. The problem is the carbohydrates in the diet, their effect on insulin secretion, and thus the hormonal regulation of homeostasis—the entire hormonal ensemble of the human body. The more easily digestible and refined the carbohydrates, the greater the effect on our health, weight, and well-being.
3. Sugars -sucrose and high-fructose corn syrup specifically—are particularly harmful, probably because the combination of fructose and glucose simultaneously elevates insulin levels while overloading the liver with carbohydrates.
4. Through their direct effect on insulin and blood sugar, refined carbohydrates, starches, and sugars are the dietary cause of coronary heart disease and diabetes. They are the most likely dietary causes of cancer, Alzheimer’s disease, and the other chronic diseases of civilization.
5. Obesity is a disorder of excess fat accumulation, not overeating, and not sedentary behavior.
6. Consuming excess calories does not cause us to grow fatter, any more than it causes a child to grow taller. Expending more energy than we consume does not lead to long-term weight loss; it leads to hunger.
7. Fattening and obesity are caused by an imbalance- a disequilibrium – in the hormonal regulation of adipose tissue and fat metabolism. Fat synthesis and storage exceed the mobilization of fat from the adipose tissue and its subsequent oxidation. We become leaner when the hormonal regulation of the fat tissue reverses this balance.
8. Insulin is the primary regulator of fat storage. When insulin levels are elevated - either chronically or after a meal – we accumulate fat in our fat tissue. When insulin levels fall, we release fat from our fat tissue and use it for fuel.
9. By stimulating insulin secretion, carbohydrates make us fat and ultimately cause obesity. The fewer carbohydrates we consume, the leaner we will be.
10. By driving fat accumulation, carbohydrates also increase hunger and decrease the amount of energy we expend in metabolism and physical activity.
Friday, March 26, 2010
Thursday, March 25, 2010
Conspiracies, wild accusations, and a hypothesis to self test. I'm thinking if you eliminate wheat but pound down the HFCS, you'll still have the belly!
Tuesday, March 23, 2010
The interesting parts of this article include a basket full of citations about the potential risks posted by rampant chemicals in our food. Makes a good case for aluminium water bottles and organic, and/or free range/grass fed meats.
However, take note that every study cited is working on 'observational' data, good only to establish an hypothesis, but in no way proof of cause and effect relationships.
Saturday, March 20, 2010
"The report just released from the Nurses' Health Study, in a rather understated way, offers 2 million American women who have had breast cancer some vital and actionable information. Taking a single aspirin tablet—a baby aspirin or one adult pill—every other day can be lifesaving. (In fact, were these aspirin tablets a hot new biotech drug, we would be popping champagne right now.) The long-term, low-dose aspirin program was initiated a year or more after the cancer diagnosis as an add-on to treatment, not as a substitute for it, to control the fate of tumor cells silently left behind.
The surprise finding: Those who made aspirin a regular habit, consuming low doses two to five times a week (mostly to help their hearts), were 71 percent less likely to have a deadly recurrence of their breast cancer compared to those who were taking little or no aspirin."
Walking Out Cured
"It's a wonder no one has tried to have Mary Vernon's medical license revoked. Since 1999, the 52-year-old family doctor has been treating diabetic patients in Lawrence, Kansas, with an approach that was abandoned by most physicians in the 1930s. Worse, this Depression-era remedy is the opposite of the current guidelines established by the American Diabetes Association, a nonprofit organization that spent nearly $51 million on research in 2005, and so should know a thing or two about how to handle diabetes. There's no question that Dr. Vernon is trouble -- but for whom? Not her patients, that's for certain. They just won't stay sick. People walk into her office afflicted with type-2 diabetes and, by every objective medical measurement, walk out cured. There's $51 million that says that isn't supposed to happen, not in a clinic in Kansas, and definitely not as a result of cleaning out the refrigerator. "My first line of treatment is to have patients remove carbohydrates from their diets," explains Dr. Vernon, a petite, energetic mother of two who also serves as the president of the American Society of Bariatric Physicians. "This is often all it takes to reverse their symptoms, so that they no longer require medication.""
This piece closely mirrors what Taubes reports in Good Calories Bad Calories. Like a tragic play in the way it has played out for diabetics. How lucky for the ones who walked through Dr. Vernon's door.
Friday, March 19, 2010
Thursday, March 18, 2010
Coronary atherosclerotic plaque and bone health are intimately interwoven. People who have coronary plaque usually have osteoporosis; people who have osteoporosis usually have coronary plaque. (The association is strongest in females.) The worse the osteoporosis, the greater the quantity of coronary plaque, and vice versa. The two seemingly unconnected conditions share common causes and thereby respond to similar treatments.
I have seen many women increase bone density using these strategies . . . without drugs of any sort.
1) Vitamin D restoration--Vitamin D is the most important control factor over bone calcium metabolism, as well as parathyroid function. As readers of this blog already know, gelcap forms of vitamin D work best, aiming for a 25-hydroxy vitamin level of 60-70 ng/ml. This usually requires 6000 units per day, though there is great individual variation in need.
2) Vitamin K2--If you lived in Japan, you would be prescribed vitamin K2. While it's odd that K2 is a "drug" in Japan, it means that it enjoys the validation required for approval through their FDA-equivalent. Prescription K2 (as MK-4 or menatetranone) at doses of 15,000-45,000 mcg per day (15-45 mg), improves bone architecture, even when administered by itself. However, K2 works best when part of a broader program of bone health. I advise 1000 mcg per day, preferably a mixture of the short-acting MK-4 and long-acting MK-7. (Emerging data measuring bone resorption markers suggest that lower doses may work nearly as well as the high-dose prescription.)
3) Magnesium--I generally advise supplementation with the well-absorbed forms, magnesium glycinate (400 mg twice per day) or magnesium malate (1200 mg twice per day). Because they are well-absorbed, they are least likely to lead to diarrhea (as magnesium oxide commonly does).
4) Alkaline potassium salts--Potassium as the bicarbonate or the citrate, i.e., alkalinizing forms, are wonderfully effective for preservation or reversal of bone density. Because potassium in large doses is potentially fatal, over-the-counter supplements contain only 99 mg potassium per capsule. I have patients take two capsules twice per day, provided kidney function is normal and there is no history of high potassium.
5) An alkalinizing diet--Animal products are acidic, vegetables and fruits are alkaline. Put them together and you should obtain a slightly net alkaline body pH that preserves bone health. Throw grains like wheat, carbonated soft drinks, or other acids into the mix and you shift the pH balance towards net acid. This powerfully erodes bone. Therefore, avoid grains and never consume carbonated soft drinks. (Readers of this blog know that "healthy, whole grains" should be included in the list of Scams of the
Century, along with Bernie Madoff and mortgage-backed securities.)
6) Strength training--Bone density follows muscle mass. Restoring youthful muscle mass with strength training can increase bone density over time. The time and energy needs are modest, e.g., 20 minutes twice per week.
Note that calcium may or may not be on the list. If on the list at all, it is dead last. When vitamin D has been restored, intestinal absorption of calcium is as much as quadrupled. The era of force-feeding high-doses of calcium are long-gone. In fact, calcium supplementation in the age of vitamin D can lead to abnormal high calcium blood levels and increased heart attack risk.
Wednesday, March 17, 2010
Read more: http://www.time.com/time/magazine/article/0,9171,1558294,00.html?loomia_si=t0:a16:g2:r1:c0.15245:b24314702&xid=Loomia#ixzz0eigxOd4K
Interesting results. Would be interesting to dig into the study to piece together what the authors meant by the final para, and which if any inconsistencies could be found. The fact that they were looking means they likely believed the 'animal bad plant good' dogma to begin with. How did that affect their analysis?
Tuesday, March 16, 2010
Another brilliant post from Heartscan about vitamin K.
BLUF: you need it, and getting isn't simple. How much you need and exactly how high the impact will be isn't known. Most usable tip - eat your green leafy vegatables with good quality oil!
Monday, March 15, 2010
My friends over a CrossFit Rockwall do a marvelous job describing most of what anyone needs to know about dairy.
I stopped drinking milk when I learned it has been shown to significantly increase insulin levels over equivalent quantities of non-milk sugars. My perception was that both body fat and inflammation levels decreased when I stopped co milk. That said, I don't have access to raw milk, which might have a lower insulin and therefore inflammation impact.
Sunday, March 14, 2010
This is a great summary of the issues, but of course, not completely accurate. For one thing, the study he cites was a survey of a collection of observational studies, which of course cannot prove causation one way or the other (see this post on the actual study: http://fireofthegodsfitness.blogspot.com/2010/02/meta-analysis-considering-impact-of-fat.html).
My biggest gripe with the doc's post is he pumps REAL food, but then includes whole grains which are only REAL food if you happen to be a bird! Dump the wheat and you lose nothing you need, and many things you don't need.
Saturday, March 13, 2010
Friday, March 12, 2010
" believe that we can all agree that the commonly obtained Friedewald LDL cholesterol (what I call "fictitious" LDL cholesterol) is wildly inaccurate. 100%--yes, 100% inaccuracy--is not at all uncommon.
This flagrant inaccuracy, unacceptable in virtually every other discipline (imagine your airplane flight to New York lands in Pittsburgh--close enough, isn't it?), is highlighted in the University of California study by Stanhope et al I discussed previously.
32 participants consumed either a diet enriched with either fructose or glucose. Compared to the effect of glucose, after 10 weeks fructose:
Increased LDL cholesterol (calculated) by 7.6%
Increased Apoprotein B (a measure of the number of LDL particles) by 24%
Increased small dense LDL by 41%
Increased oxidized LDL by 12.6%
In other words, conventional calculated LDL substantially underestimates the undesirable effects of fructose. The divergence between calculated LDL and small LDL is especially dramatic. (By the way, this same divergence applies to the studies suggesting that calculated LDL cholesterol is reduced by low fat diets--While calculated LDL may indeed be reduced, small LDL goes way up, a striking divergence.)
This is yet another reason to not rely on this "fictitious" LDL cholesterol value that, inaccuracies notwithstanding, serves as the foundation for a $27 billion per year industry."
Thursday, March 11, 2010
- Mario Andretti (Italian-born American car racer)
Thanks to CrossFit.com
Wednesday, March 10, 2010
The article totally underplays the significance of this outcome. LDL and total cholesterol are correlated with CVD and other diseases of civilization (DOC), but only sometimes, and in some populations. However, high triglycerides, high blood pressure, low HDL, and glucose intolerance is metabolic syndrome - these are unquestionable precursors to CVD and DOC. If you can break this profile, you are getting well and preventing damage to your body. The 'bad' cholesterol it turns out is only 'bad' in one of several forms - small, dense LDL (this is latest thinking but not proved; still, just as proved as the diet-heart hypothesis). Small dense LDL are lipoproteins result as an end stage product of VLDL (very low density - because they are filled with fat). When on a high carb diet, the body converts a lot of the sugar to tryglycerides (TG) in the liver. VLDL are created to shunt the TG around the body. As VLDL deposit their stores of TG, and become less full, they become 'small, dense LDL' and are easily oxidized. The current theory is the small dense LDL goes to the site of arterial injury as a repair team (cholesterol is not water soluable so is critical to cell structure), but instead gets 'stuck' to the artery through oxidation. The artery gets "rust" instead of repair. Now there's an even greater need for repair, and the construction of a plaque has begun. There are other mal-adaptive reactions to high blood sugars - AGE (advanced glycation end products) which also contribute to atherosclerosis by binding the artery protein together, preventing arterial expansion/flexibility. Small dense LDLs are very susceptible to glycation. The best way to reduce AGE - reduce blood sugar levels (intermittent fasting is one way to do this). TGs, thus small dense LDLs, plus AGEs are reduced through carb restriction.
This process of small, dense LDL creation is one of the elements of Metabolic Syndrome (also called Syndrome X). Metabolic syndrome is interrupted through carb restriction. It seems there is a subset of folks who cannot toerate high saturated fat levels, but a larger subset, much larger, than cannot tolerate chronicly high carb intake (100g/day being 'high'). Metabolic syndrome is the most likely driver of the DOC. In contrast with the 'diet-heart' hypothesis that began its most recent lifespan with Ancel Keys, the metabolic syndrome model is not controverted by any intervention study of which I'm aware, and is consistent with all observed criteria for reducing chronic diseases from Alzheimer's to CVD. Metabolic syndrome is also avoidable. Keep carb intake to 50-100g per day, and measure the results via blood pressure, triglycerides, HDL levels, and glucose tolerance. Adjust carb levels as necessary.
Fascinating analysis. I like the doc's conclusion.
"So perhaps mustard isn't exactly a super health food. But it may have some bona fide health effects and should be used generously especially if you are concerned about blood sugar and inflammatory phenomena."
Tuesday, March 9, 2010
Articulates the story fairly well, but doesn't tell us - how to live well and eat less? There is an answer - eat meat and vegetables, nuts and seeds, some fruit little starch and no sugar.
Monday, March 8, 2010
"Bottom line for you - if you have high blood pressure, you should worry about salt intake. If you do not have HBP, you should only worry about salt if you have nailed down the big pieces, have a stable, healthy body composition and good HDL and triglyceride numbers, and want to move from healthy to "friggin' perfect.""
Very interesting study. Can't conclude a whole lot from studies on rats, but when a study on rats confirms something I already believe is true - we eat too many omega 6 fatty acids - it's worthy of notice.
"According to Oprah's biography, she was born to a poor single mother in rural Mississippi. I would assume that her mother, like most poor rural people, consumed primarily a carb-based diet. Why? Carbs are cheap. One of the reason poor people are fatter in general than well-off people, is that poor people eat a lot more carbs for budget reasons. Another reason poor people are fatter is a little less known, but surely applies to Oprah.When pregnant women load up on refined carbohydrates during pregnancy, especially during the first trimester, they end up damaging the developing pancreas of the fetus. The pancreas is pretty much developed during the first trimester, so a chronic high load of glucose in the mother's blood that crosses the placenta ends up programming the fetal pancreas in much the same way that a huge chronic glucose load over a long time in adults creates insulin resistance. This situation has been published about extensively in the medical literature. The phenomenon is called fetal programming. Babies born are basically programed to become insulin resistant and obese. These kids tend to develop obesity and insulin resistance more easily than others and have a tougher time dealing with it. I'm sure that Oprah falls into this category.Just like any adults who have glucose intolerance, insulin resistance, and/or diabetes, these fetally-programmed people tend to do better on low-carbohydrate diets than on low-fat/high-carb diets."
Friday, March 5, 2010
As often as possible during the off-season, James Upham, U.S. Biathlon's development coach, points his athletes in one direction: up. Hill work is the fastest way to push into the range of your max heart rate while simultaneously building strength, power, and technique. "One legendary drill is the whiteface workout," Upham says with a devilish laugh. "It's really fun for coaches to watch. You bound straight uphill for 12 minutes, alternating 15 seconds of moving with 15 seconds of rest. Then you take 5 minutes off and do it again.""
Thursday, March 4, 2010
"Rob Roy, the veteran coach who oversees Chris Klug's training, uses an obstacle course to teach snowboarders to look ahead instead of down at their feet. If you play basketball or soccer, you can benefit, too. Try the sidewinder, from plyometrics expert Donald Chu, Ph.D. Line up three cones 3 to 4 feet apart. Set up a fourth cone 20 yards away. Keeping your eyes ahead, shuffle sideways, weaving through the first three cones from left to right, and then back from right to left. Now pivot and sprint 20 yards to the fourth cone. Return to the obstacle course using a quick, sideways shuffle. Repeat 3 times."
Also a good summary of plank variants for someone who's looking for an unloaded approach to building or rebuilding core strength.
Wednesday, March 3, 2010
Jason Hartman likes to wow new bobsledders with his magical jumping drill. First, he tests their maximum vertical leap. Then he has them do a set of heavy squats before jumping again. Without fail, they'll jump several inches higher after blasting their legs with the squats.
"It's called post-activation potentiation," Hartman explains. The theory is that the squat activates bands of last-resort muscle fibers called "high-threshold motor units." Your body keeps HTMU fibers in reserve for emergencies and only the most strenuous jobs, so the trick is to recruit them voluntarily.
Unlike with the training regimen Hartman typically uses, you don't want a lot of reps here. "I tend to make sure the resistance is high but not maxed out. Just do a small amount of volume to wake up your muscles." And once you've recruited that HTMU oomph to leap those extra inches, Hartman says, the gains remain; after your body learns that it can jump 32 inches instead of 30, you can do it all the time, even without the squat-rack warmup.
Tuesday, March 2, 2010
""High-intensity interval training is twice as effective as normal exercise," said Jan Helgerud, an exercise expert at the Norwegian University of Science and Technology. "This is like finding a new pill that works twice as well ... we should immediately throw out the old way of exercising."
Intense interval training means working very hard for a few minutes, with rest periods in between sets. Experts have mostly tested people running or biking, but other sports like rowing or swimming should also work.
Helgerud recommends people try four sessions lasting four minutes each, with three minutes of recovery time in between. Unless you're an elite athlete, it shouldn't be an all-out effort.
"You should be a little out of breath, but you shouldn't have the obvious feeling of exhaustion," Helgerud said.""
Monday, March 1, 2010
Hope we'll see these on more and more sidelines.
BLUF: Burning up time doing cardio work is a bad deal for your strength, your health and likely also for your longevity. Why? it's well known that heavy duty cardio is muscle consuming, and makes you weaker. It also subjects you to oxidative stresses that you can live better without. There's not really an upside - weak core, flexibility challenges, and all you gain for all that time spent is the ability to work not very hard (maximum of 40% of your total output) for a long time.
THere's only one reason to do this to yourself - you just love it. Otherwise, go for high intensity and lower duration; 20 minutes max!