October 27, 1997
- Can exercise preserve youthful metabolic rate?
- Bone mineral content and body fat vs muscle mass
- Obesity and muscle development
- Wheat and behavioral problems
- P.S. on European estrogen dosages
- Great quotations: Picasso on youth
Can regular exercise preserve youthful metabolic rate?
Resting metabolic rate (RMR) generally declines with age. Low RMR correlates with obesity and premature mortality. Is the decline in RMR inevitable, or can exercise maintain youthful RMR?
This study compared 65 sedentary and physically active (runners and swimmers) premenopausal and postmenopausal women. In premenopausal women (age 21-35), RMR was tested during the follicular phase, when it is somewhat lower (progesterone raises RMR). The age range of postmenopausal women was 50-72; of premenopausal women, 21-35. Half of postmenopausal women in each group used HRT. All were non-smokers.
WHR stands for Waist/Hip Ratio, a measure of central obesity (the dangerous kind). VO2max indicates maximum oxygen consumption, a measure of aerobic fitness. Here are the results comparing the sedentary and exercising premenopausal and postmenopausal women (sorry, my email messes up the table format, so I have to specify bit by bit; the figure for premenopausal women is always given first):
BMI in sedentary women showed an increase from 22.6 to 27; in runners, from 19.6 to 21.
Percentage of body fat in sedentary women showed an increase from 27% to 39.8%; in runners, from 15.4% to 25.7%.
WHR in sedentary women showed an increase from .75 to .83; in runners, it stayed the same at .74.
VO2max in sedentary women showed a decrease from 34.3 to 22; in runners, from 53 to 38.
RMR in sedentary women showed a decrease from 57 cal/h to 52 cal/h (10% decrease); in runners, from 59 to 57 cal/h (4% decrease).
Thus, the decrease in RMR in runners could be classified as slight. In fact, the authors enthusiastically conclude that exercise prevents the age-related decline in RMR. They sound a warning about obesity: “This age-related difference in energy expenditure, if uncompensated by a decrease in energy intake, would equate to about 4kg/year greater increase in body weight in sedentary women (. . .) Even modest weight gain in women with advancing age is associated with markedly increased risk of diabetes, coronary artery disease, and overall mortality.”
Still, the comparison of runners and swimmers in the same study leaves some questions unanswered. The swimmers exercised less: an average of 7.6 hours a week compared to 10.9 hours a week for runners. Itâ€™s not surprising that postmenopausal swimmers had a higher average BMI than postmenopausal runners (23.3 vs 21) and a higher percentage of body fat (29.4 vs 25.7). Yet the postmenopausal swimmers had the same RMR as the postmenopausal runners: 57 cal/h. Thus it may take considerably less exercise to maintain a high RMR than the amount needed to significantly retard the creeping middle-age weight gain. As always, the situation is complex.
Still, there is no arguing with the main point: exercise seems effective in preserving a higher RMR.
Note, however, that percentage of body fat did go up with age even in exercisers. In other words, there was a negative change in muscle to fat ratio even in exercisers. Itâ€™s possible that this muscle loss canâ€™t be prevented with aerobic exercise alone, without growth hormone replacement.
A study comparing premenopausal and postmenopausal weight lifters is also badly needed.
Van Pelt RE et al. Regular exercise and age-related decline in resting metabolic rate in women. J Clin Endo Metab 1997;82:3208-12
BUT WHEN IT COMES TO STRONG BONES . . .
FAT OVER MUSCLE AGAIN?
One recent study examined bone mineral content in 301 elderly men and women (“elderly” was defined as 65 or over). In women not taking HRT, bone mineral content (BMC) correlated more highly with fat than with muscle mass.
In fact, there was no significant correlation between BMC and muscle mass in women.
In women on HRT there was no significant correlation between either fat or muscle and BMC.
The authors conclude, “This study suggests that fatness may be more important than muscle in maintaining bone mineral in elderly women not taking estrogen.”
(“Fatness” seems to be the trendy term for obesity, or body fat in general, as in “the age at menarche depends on fatness.”) One possible explanation is that the higher estrone levels in obese women play a significant role both in intestinal calcium and silicon absorption, the synthesis of Vitamin D3, and in direct bone building through the action of estrone on the osteoblasts. Add to this the fact that simply carrying the extra weight seems to strengthen bone (see Dr. Vangorâ€™s commentary below).
The study also found that IN MEN muscle mass was associated with bone mineral content. This is not surprising, since in men testosterone maintains both muscle mass and bone health. Muscle mass in men is closely associated with testosterone levels.
This finding should not be taken to mean that weight-bearing exercise is useless for women in terms of bone health. On the contrary. Exercise is vital in preserving both muscle and bone; without exercise, atrophy sets in.
This is seen not only in immobilized patients, but also when astronauts stay for a significant period of time in zero gravity and thus are getting no exercise because they are weightless and movement is effortless. Also, those of you who have ever worn a cast were probably shocked by how skinny your arm or leg looked when the cast came off.
As for the inescapable conclusion that obesity has some health benefits, oh, well . . . please see below.
Baumgartner RN et al. Association of fat and muscle masses with bone mineral in elderly men and women. Am J Clin Nutr 1996; 63 (3): 365-72
DR. ANDREA VANGOR’S COMMENTS ON OBESITY AND MUSCLE MASS
DON’T MISS THIS ONE!
Andrea Vangor, Ph.D., Anatomy, has contributed this fascinating commentary in response to the point about the probable obesity of Cauleyâ€™s subjects who had both superior grip strength and high native estrogen levels:
“I wonder if researchers are taking into consideration the training effects of obesity per se. I used to teach human dissection, and so I can tell you that fat people who were active up to the point of death make the best cadavers. Great muscles and they donâ€™t dry out.
Most cadavers are elderly, for obvious reasons. But they are not all alike in terms of muscle mass and bone development. You often know from the information on the cause of death whether the person was inactive for a long time or not. Thin people, especially the elderly, have thin, wispy muscles.
They have so little work to do against gravity. Fat people who are bedridden for a long time have mounds of fat and thin wispy muscles.
But fat people, even elderly, who died of some sudden stroke or heart attack or car wreck have lovely muscles and robust bones under the fat.
Being obese is like continual weight training. A fat person who moves continually against gravity and inertia is de facto an athlete. You can compute the increase in load on muscles and bones due to carrying the extra weight as a problem in biomechanics. Talk about grip strengthâ€”it is not a function of the intrinsic hand muscles so much as the forearm flexors; these muscles stabilize the elbow and the wrist joint as well as flexing it and the fingers, and they are heavily recruited and become strong in an active obese person.
I would assume that Cauleyâ€™s obese subjects were not bedridden cancer patients, but active people in a constant state of built-in weight training.”
Fascinating! Itâ€™s a shame that Cauley did not investigate the connection between grip strength, estrone and estradiol levels, and obesity.
Dr. Vangorâ€™s comments confirm my guess in CHW#1 that the obese subjects also had the most grip strength.
Muscle atrophy in the elderly is a serious problem. Weâ€™ve been so fixated on bone loss that the fact that we lose an estimated 6 lbs of muscle for every decade after 20, and this loss accelerates after menopause, has been largely uncommented on. Let us hope that the emerging growth hormone replacement therapy will bring muscle atrophy into public focus.
IF YOU DO NOTHING, EXPECT TO LOSE ABOUT 40% OF YOUR MUSCLE MASS BETWEEN THE AGES OF 50 AND 80.
The dark side of obesity as continual weight training is the horrendous stress on the joints. Most of the generalized osteoarthritis patients are obese.
The politically incorrect connection between female obesity and the prevention of bone, muscle, and skin atrophy may make us squirm a little, but it has to be acknowledged. Still, obesity is a devilâ€™s bargain: the health risks outweigh the benefits. Those with BMI over 30 have twice the all-cause mortality, and triple the cardiovascular mortality. There are no obese centenarians.
Then what about the frequent advice to menopausal women along the lines of “Go ahead, put on those extra pounds, body fat is your best natural source of hormones after the ovaries quit!” Or even Gail Sheehyâ€™s innocent-sounding motto of “sacrificing the fanny to save the face” (since chubby women have younger-looking faces)? The advocates of calorie restriction seriously disagree. Hence the Life Extension Foundationâ€™s motto: “Eat like a bird, exercise, and replace those hormones!” (Birds actually eat a lot for their body weight, but we wonâ€™t pick on that.) Iâ€™d like to modify this as follows: “Eat a low-glycemic diet, make sure your exercise regimen includes weight lifting, and yes, do replace those hormones!”
Thinner IS better, as long as you use optimal, well-balanced natural hormone replacement to overcome the postmenopausal hormonal disadvantage of thinness, exercise (but not to excess), and eat a diet sufficient in protein and healthy fats.
WHEAT INTOLERANCE AND BEHAVIORAL DISORDERS â€”
MORE FROM DR. ANDREA VANGOR
“Iâ€™d be really interested in following up on the wheat-celiac disease connection. I work on severe behavior disorders of children and advocate strongly for a multiple elimination diet. Cow-dairy and wheat are at the top of the list, after artificial chemicals. Wheat is an especially noxious sensitizer because it can hang around in the body for three days after consumption, affecting the production of endogenous opioids in the brain. A recent client found that he suffered a marked decrease in obsessive-compulsive behavior when he stopped eating wheat. Thereâ€™s a patchy but tantalizing literature on this subject.”
Again, this is fascinating! I suspect that additional factors may be involved. For instance, we know that wheat products contain PHYTATES, and phytates block the absorption of essential minerals such as calcium and magnesiumâ€”both among natureâ€™s best tranquilizers. Weâ€™ll have an article on phytates coming up soon, graciously contributed by Dr. David Zava.
Also, a diet heavy on bread and breakfast cereals probably contains excess carbohydrates, especially the harmful processed carbohydrates that lead to a glucose surge followed by an insulin surge, quite likely followed by hypoglycemiaâ€”this blood sugar roller-coaster by itself could lead to neurotransmitter imbalances and mood and cognitive disturbances.
The difference between a high-protein, wheat-free breakfast and a protein-deficient, fatty-acid-deficient, cereal-based breakfast could be night and day for anyone who tends to underproduce dopamine and other neurotransmitters, as may be the case with attention-deficit-disorder children and adults.
Bottom line: Wheat may be harmful for more than one reason. Many, perhaps even most people would do well to perform a simple experiment: eliminate all wheat products for a month and see how you feel.
Note: beans, especially soybeans, also contain phytates, but their levels can be reduced through overnight soaking. Soaking, sprouting, and fermenting are all traditional methods of preparing seed products. More on this in the article by Dr. Zava.
If you eliminate wheat, and it turns out that you still suffer from some bloating, headaches, and low energy, experiment with eliminating white potatoes also. Donâ€™t worry: there are plenty of health-giving carbohydrates to take the place of the trouble makers. As Jim Barron points out in CHW 1, there are no nutrients in grains (or potatoes) that cannot be easily obtained from other sources.
A P.S. ON EUROPEAN ESTROGEN DOSAGES
You may remember the lively article by Elizabeth (CH 3), and the fact that she was on 1.25mg Premarinâ€”twice the typical American dosage. She has now switched to estradiol, 4mg/day, taken sublingually (actually she prefers to put the tablet between gum and cheek). Again, this is the more realistic translation of the Premarin dosage than would be common in the minimalist-minded U.S., where we think that 2mg is the maximum dose. In Europe, thatâ€™s actually the minimum dose, the starting dose for menopausal women. The typical European dosage range is 2-4mg. In Germany, 1mg estriol is added. This is the dosage range that appears to produce excellent cardiovascular benefits and help preserve the waistline and muscle strength.
How does one make it safe? By taking sufficient progesterone on daily basis. Think of the birth control pill: the higher the dose of estrogen, the higher the dose of Progestin has to be. The Pill is safe because the hormones are well-balanced. I canâ€™t understand why HRT is not generally thought of in these terms.
Elizabeth is still taking 10 mg of Provera/day (continuous regimen). She tried 15mg, but the side effects hit.
Including small doses of testosterone, DHEA, and Pregnenolone in the replacement regimen probably also increases safety. Nature has designed a system of hormonal checks and balances; it makes sense to replicate this system, as opposed to the mono-hormone approach.
GREAT QUOTATIONS: PABLO PICASSO ON YOUTH
“It takes a long time to become young.”
The material contained herein is intended as information only, and not as medical advice.