Simple Truths About Muscle Growth (part 2)

In previous posts I have stressed the importance of the IGF-1s (Insulin-like growth factors, type 1) in promoting body growth. To reiterate the main message of my last (post): the IGF-1s are likely to be our most important growth promoters, particularly with reference to all types of muscle, bone and connective tissues. Importantly, these are the tissues an athlete must fortify in order to continue making gains.

Not too long ago, however, it was believed (wrongly) that the only way to produce IGF-1 was in response to another hormone called Growth Hormone; it is by no coincidence that “growth” is explicitly stated in this important hormone’s name. This story has recently been revised, which has very important implications for how an athlete trains, rests and eats...

Go here for more information about the IGF-1s:

There are Two Pathways that Produce IGF-1:

Pathway 1 (traditionally recognized): Growth Hormone Stimulates IGF-1 Production for Systemic Distribution

Particularly, while we sleep, IGF-1 is produced from the liver in response to Growth Hormone (GH) that in turn, is released from a gland at the base of the brain called the anterior pituitary. Thus, the old dogma states that GH (released from the brain) stimulates the liver to produce IGF-1 distally, that then enters the blood stream to stimulate muscle and bone growth systemically; that is, delivered via the blood derived fluids that baths all our muscles and bones. This was known as the GH axis.

Importantly, the GH-mediated rise in IGF-1 is most pronounced while we sleep, declines in advanced age and is attenuated by heavy alcohol consumption, helping to explain the anabolic effects of rest and alcohol moderation…

See this link for more information about Growth Hormone:

Pathway 2: Muscle Makes its Own IGF-1 for Local Use

We’ll it turns out that muscle does not (more precisely, cannot) simply wait for the brain “to decide” when it needs IGF-1. Muscle has thus evolved a way of producing its own supply of IGF-1 on demand, when challenged by a physical stress. That is, exercise. Exercise is one of the most potent stimulators of local IGF-1 production by muscle.  Nonetheless, the IGF-1 produced by muscle can also reach neighboring tissues such as bone, to assist in their development as well.

Exercise-induced IGF-1 production makes practical sense and “feels right” for must of us as our practical experience has shown us that exercise causes muscle growth and increases our strength. Even more, not exercising causes our muscles to shrink, or atrophy. Why do you think?

A Trick to Optimize Muscular IGF-1 Production

An unexpected nutritional intervention has been recently shown to augment the expression of IGF-1 in isolated muscle cells grown outside the animal, independently of exercise. That is, though muscle cells in a plastic dish can’t undertake training, they respond to this nutritional intervention just the same.  Obviously, this has important implications for the athlete or clinician trying to promote muscle or bone development. How to put this into play in “real” terms will be the topic of subsequent posts.

If you are in a hurry for the answer click here: guide

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