&gt; <i>Long-term exercise</i> is known to reduce serum levels of growth stimulating hormones. In contrast, the endocrine effects of <i>acute endurance exercise</i> include increased levels of mitogenic factors such as GH and IGF-1.<p>Two points:<p>1. how to best understand &quot;long-term exercise&quot; vs &quot;acute endurance exercise&quot; in lay terms here roughly?<p>2. how mitogenic is growth hormone vs IGF-1? Raised GH seems to raise IGF-1 &quot;usually&quot;, but for example during fasts for more than a day or couple of days, GH weirdly seems to go up very drastically while of course IGF-1, insulin, mTOR, leptin all trend ever-lower<p>Always wondered whether the bodybuilders tried to raise GH for its own sake primarily or just in order to initiate the cascade of other &quot;growth &amp; proliferation&quot; pathways..