Tuesday, February 5, 2008

Why is weight-training healthy?

A new study indicates why resistance training - more than endurance training - is good for you! The particular type of muscle growth prompted by resistance training counteracted the deleterious effects of a dodgy diet.

Fast/Glycolytic Muscle Fiber Growth Reduces Fat Mass and Improves Metabolic Parameters in Obese Mice

In contrast to the well-established role of oxidative muscle fibers in regulating whole-body metabolism, little is known about the function of fast/glycolytic muscle fibers in these processes. Here, we generated a skeletal muscle-specific, conditional transgenic mouse expressing a constitutively active form of Akt1. Transgene activation led to muscle hypertrophy due to the growth of type IIb muscle fibers, which was accompanied by an increase in strength. Akt1 transgene induction in diet-induced obese mice led to reductions in body weight and fat mass, resolution of hepatic steatosis, and improved metabolic parameters. Akt1-mediated skeletal muscle growth opposed the effects of a high-fat/high-sucrose diet on transcript expression patterns in the liver and increased hepatic fatty acid oxidation and ketone body production. Our findings indicate that an increase in fast/glycolytic muscle mass can result in the regression of obesity and metabolic improvement through its ability to alter fatty acid oxidation in remote tissues.

The associated press release explains things further:
Researchers used a genetic trick in obese mice that caused the mice’s muscles to bulk up as though they had been lifting weights. The researchers found that the “genetically reprogrammed” mice lost fat and showed other signs of metabolic improvement throughout the body. What’s more, those benefits were seen even though the mice continued eating a diet high in both fat and sugar and didn’t increase their physical activity at all.

Walsh’s group developed mice in which they could turn type II muscle growth on or off by flipping a genetic switch specifically in skeletal muscle. The gene they manipulated, known as Akt1, is preferentially activated in skeletal muscle in response to resistance training, but not endurance training, the researchers knew.

Rather than becoming strong and fat “sumo mice” as some of the researchers had expected, the modified mice gained type II muscle and strength while they lost fat. The mice also showed a resolution of hepatic steatosis, otherwise known as fatty liver, and improvements in a variety of other metabolic parameters. The Akt1-driven growth of skeletal muscle counteracted the usual effects of a high-fat, high-sucrose diet on patterns of gene activity in the liver and increased the breakdown of fatty acids there, the researchers showed.

This is an interesting one and shows that there is more to health than diet. There is an impact from exercise too and specifically from resistance training.

This is a call to us all to do more training to focus on the fast / glycotic muscle fibres....

You can read more about the research at:

Weight training melts fat and improves metabolism, says study of obese mice
'Weight training' muscles reduce fat, improve metabolism in mice


Peter said...

Interesting. Time to get the pushbike out again and see how high a gear I can get up the hill out of the village in... Higher the better from the sound of the paper!


Chris said...

Thanks for the comment Peter. I'd be quite interested in the compostion of the mice diet here - all it says is high fat and high sucrose.

Just as the orthodoxy in diet is low fat, the orthodoxy in exercise tends to be endurance / aerobic. This study (and others)challenges things a bit and indicates the value of anaerobic exercise (ie.e hard work!)

lazur said...

Nonetheless, many of the most overfat men in the world are also the most muscular. There's got to be more to this.

Peter said...

Hi Chris,

the archetypal high fat diet is D1245 or a derivative. I think the sucrose is quite important, though you can do it with glucose, and casein is insulogenic too. But resistance training might just be the ticket if it really does do the same thing, metaboliclally, as was done to the mice.

I don't have the time for sustained aerobic stuff, so this suits my biases nicely!


Rannoch Donald RKC said...

There have been a number or studies and articles recently that refute the conventional wisdom of aerobics and high carbs. Unfortunately for those who would benefit most from weights and lower carb intervention, the effort of training with sufficient intensity without their much expected "carb hit" is simply beyond their scope.

How's your training coming on Chris?

All the best


Chris said...

Hi Rannoch

Thanks for the comment - it is good to see the conventional wisdom challenged a bit, maybe eventually some sense will prevail. People like Mark Sisson and Eades are writing some good accessible stuff now.

My training is going well just now. Usually one "grind" strength day, one intervals day (usually kb snatches 15/15 or something similar) and one day of circuits. We need to meet up sometime.

Roston said...

I am real content with the mentation and don't conceive equivalent adding anything in it. It a perfect response.
weight training

viagra online said...

That's right, actually the resistance excercises are indeed more effective than endurance ones, that, and a da*m good healthy plan or diet, would be the best for your body!

Anonymous said...

Whatever you decide to do, I recommend going on a diet plan as well. No matter what kind of weight lifting you do, it won't work unless you are on a good diet. Check out FitClick.com for the best diet plans to do while weight training.

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weight training ensures a few years of life more for healthy people. in the other hand die young is a better choice.