There is a popular (e.g. link 1, link 2) theory, that is, if you train big muscle groups (e.g. legs, chest), it will increase the overall growth of muscles all over the body; the trained muscle will release signals (what are they?) into the blood stream and in turn, triggers the release of muscle growth/repair hormones (insulin-like growth factor?) which have effects on any (skeleton) muscle cells.

Is this story true? Will the muscle growth/repair hormones also enhance the smooth muscle or cardiac muscle?

  • I think what you're referring to is performing compound movements. But, I've never heard of the second part of your theory - "trained muscles releasing signals". Can you share any more details about this "popular theory"?
    – rrirower
    Jan 8, 2016 at 20:08
  • Don't have the time to look into now, but I think this is along the lines of "big compound lifts increase testosterone production", which I think is true to small degree.
    – Eric
    Jan 8, 2016 at 20:17
  • Reddit article, but it sources a lot of the info. reddit.com/r/Fitness/comments/yv0rg/…
    – Eric
    Jan 8, 2016 at 20:18
  • Here are some examples novexbiotech.com/blog/… stronglifts.com/5-reasons-why-train-legs-squats @rrirower
    – Machine
    Jan 8, 2016 at 20:45
  • 1
    You should update your question with your references.
    – rrirower
    Jan 8, 2016 at 21:05

1 Answer 1


Performing compound exercise movements have been shown to trigger the pituitary gland to release Human Growth Hormone. HGH does not discriminate against the muscle cells it targets. In a paper titled Growth Hormone and the Heart, it was shown that

GH exerts direct effects on myocardial growth and function. Evidence from laboratory models shows that GH (or IGF-I) induces mRNA expression for specific contractile proteins and myocyte hypertrophy.


The data also support a role of GH in the maintenance of a normal cardiac structure and performance.

In fact, cardiovascular researchers have also looked to HGH in recent years as a potential benefit for those with congestive heart failure (CHF).

In summary, increasingly, scientific data exists suggesting that bio-identical hormone replacement might be crucial in maintaining adequate heart health and improving the lives of people already suffering from cardiovascular disease.

  • In the compound exercise list, squats are not mentioned. Do you think it's similar enough to the deadlift (which was mentioned) that they excluded it? Or does the squat simply not have the same effect?
    – Alec
    Jan 9, 2016 at 2:56
  • Insulin-like Growth Factor I (IGF-I) also stimulates proliferations and attenuates apoptosis of intestinal smooth muscles (c.f. ncbi.nlm.nih.gov/pmc/articles/PMC2813387/pdf/nihms-145774.pdf) So I speculate it will also improve the vein in a similar way.
    – Machine
    Jan 9, 2016 at 6:11
  • @Alec Squat is definitely an option.
    – Machine
    Jan 9, 2016 at 6:14
  • N.B. Growth Hormone and IGF-I are different proteins encoded by different genes. GH is generated by pituitary gland while IGF-I mainly comes from the liver.
    – Machine
    Jan 9, 2016 at 6:21
  • @Alec I don't think that list was meant to be complete since squats and dead lifts are often mentioned in the same sentence when referring to compound movements. I think the list was meant to be a sampling.
    – rrirower
    Jan 9, 2016 at 18:28

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