T Nation

Increased Metabolic Rate, Accelerated Aging


#1

Released: 4/26/2011 4:00 PM EDT
Embargo expired: 4/27/2011 7:00 AM EDT
Source: Endocrine Society

Findings from new study may explain why low-calorie diets are beneficial for human health

Newswise â?? Chevy Chase, MDâ?? A recent study accepted for publication in The Endocrine Societyâ??s Journal of Clinical Endocrinology & Metabolism (JCEM) found that higher metabolic rates predict early natural mortality, indicating that higher energy turnover may accelerate aging in humans.

Higher energy turnover is associated with shorter lifespan in animals, but evidence for this association in humans is limited. To investigate whether higher metabolic rate is associated with aging in humans, this study examined whether energy expenditure, measured in a metabolic chamber over 24 hours and during rest predicts natural mortality.

â??We found that higher endogenous metabolic rate, that is how much energy the body uses for normal body functions, is a risk factor for earlier mortality,â?? said Reiner Jumpertz, MD, of the National Institute of Diabetes and Digestive and Kidney Diseases in Phoenix, Ariz., and lead author of the study. â??This increased metabolic rate may lead to earlier organ damage (in effect accelerated aging) possibly by accumulation of toxic substances produced with the increase in energy turnover.â??

â??It is important to note that these data do not apply to exercise-related energy expenditure,â?? added Jumpertz. â??This activity clearly has beneficial effects on human health.â??

In this study, researchers evaluated 652 non-diabetic healthy Pima Indian volunteers. Twenty four hour energy expenditure (24EE) was measured in 508 individuals, resting metabolic rate (RMR) was measured in 384 individuals and 240 underwent both measurements on separate days. Data for 24EE were collected in a respiratory chamber between 1985 and 2006 with a mean follow-up time of 11.1 years. RMR was evaluated using an open-circuit respiratory hood system between 1982 and 2006 with a mean follow-up time of 15.4 years.

During the study period, 27 study participants died of natural causes. Researchers found that as energy expenditure increased, there was also an increase in risk for natural mortality.

â??The results of this study may help us understand some of the underlying mechanisms of human aging and indicate why reductions in metabolic rate, for instance via low calorie diets, appear to be beneficial for human health,â?? said Jumpertz.

Other researchers working on the study include: Robert Hanson, Maurice Sievers, Peter Bennett, Robert Nelson and Jonathan Krakoff of the National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, in Phoenix, Ariz.

The article, â??Higher energy expenditure in humans predicts natural mortality,â?? appears in the June 2011 issue of JCEM.

Founded in 1916, The Endocrine Society is the worldâ??s oldest, largest and most active organization devoted to research on hormones and the clinical practice of endocrinology. Today, The Endocrine Societyâ??s membership consists of over 14,000 scientists, physicians, educators, nurses and students in more than 100 countries. Society members represent all basic, applied and clinical interests in endocrinology. The Endocrine Society is based in Chevy Chase, Maryland. To learn more about the Society and the field of endocrinology, visit our site at www.endo-society.org.


#2

27 deceased participants are way too small a sample size to draw any conclusion on something as generic as natural death. Way too many variables.

Even if metabolic expenditure was correlated theres so many other things that will get you first.


#3

I mentioned in another forum that, although the results are interested, we would need to control what the participants ate in order to come to any conclusions on the metabolic rate.

A higher metabolic rate means more food needed to maintain weight and more possibilities to fuck yourself up with bad foods.


#4

If this be true then you may see me around till the 24th century.


#5

The validity is questionable but I've heard about the general concept for a while.

My view: I'd rather die stronger and younger than live forever as a fucking puss.


#6

I must admit that i didn't click on the link but it sounded to me from this that the pussies were dying earlier. Please correct me if I'm wrong. Again.


#7

If you're a bodybuilder or athlete you're almost guaranteed to have a higher resting metabolic expenditure. Muscles and hormones warrant a higher turnover of nutrients.

Ha, maybe the meek shall inherit the earth.

I'd be willing to bet my longevity on the benefits of ample nutrition and regular exercise outweighing this inferred correlation.

Interesting though.


#8

Looks like a few people didn't read the full article.

It is important to note that these data do not apply to exercise-related energy expenditure,â?? added Jumpertz. â??This activity clearly has beneficial effects on human health.


#9

Looks like a few people didn't read the full article.

It is important to note that these data do not apply to exercise-related energy expenditure,â?? added Jumpertz. â??This activity clearly has beneficial effects on human health.


#10

I was commenting on the general concept that greater metabolism = greater free radical production (as a static percentage it would increase with increased metabolism) = more cellular damage = disease.

Carrying more mass and putting more food through your system will probably burn you out earlier as a result of that concept.

My comments were not directly related to the article, but rather the general concept.


#11

Oh well then, I guess I'm living on borrowed time.


#12

Classical unproven correlation confused as potential causation. For all we know, the increased energy expenditure (respiratory) associated with morbidity could be the body working harder due to disease or aging itself. And if higher metabolic rate is the issue, why aren't they measuring thyroid hormone for instance? Anyway, I'm quite sure they know this better than I and perhaps controlled for this, but the way the article is written makes it appear as a very large assumption was made here.


#13

The concept doesn't take into account all the stuff folks around here are probably hip to, like supplementing with anti-oxidants (simple as Vitamin C, which has some anecdotal evidence for promoting longevity all on its own, the fella that first advocated mega-dosing [3-4g/day] it lived to 90 something) and all kinds of other things that are actually good for you.

Still borrowed time but not nearly as dramatic as I was joking about earlier.

I should probably be funnier, that might help.


#14

No, it DOES sound like they're talking about us. Walking around with more muscle mass will increase your Resting Metabolic Rate. Also, so will sprinting, prowler-pushing, and the vast majority of other short-burst, explosive forms of GPP T-Nation authors routinely advocate. Thats why they advocate them.

Being a bodybuilder WILL raise your RMR. I think that caveat from the article is meant to prevent people from being scared away from the AMA recommended 20min jog 3x/week.


#15

Well, the old joke for trying to live longer is that all those extra years that eating less food and non-delicious food at that is that all those extra years come at the end anyway.