Growth Hormone and Growing Kids

Most of us have heard about human Growth Hormone (hGH, thanks in large part to those like Sylvester Stallone promoting there ‘magical’ anti aging properties). hGH is a protein hormone secreted by somatotrophs in the pituitary, and is comprised of 190 amino acids. As you can tell from it’s name it plays an important role in growth (which is important to kids, who are our topic for the week). It stimulates the liver to secrete IGF-I. This stimulates cartilage cells and results in bone growth. The IGF-I also appears to be key to muscle growth because it stimulates amino acid uptake and protein synthesis in muscle. It maintains blood glucose, as well, by suppressing the insulin’s ability to stimulate glucose uptake by peripheral tissues. Release of hGH is controlled by Growth Hormone-releasing hormone (GHRH) and Ghrelin. Somatostatin (SS) inhibits the release in response to GHRH and other stimulatory factors (such as low blood glucose). Growth Hormone is stimulated by: peptides (GHRH and ghrelin), sex hormones (androgen, especially during puberty, and estrogen), deep sleep, fasting, and vigorous exercise. Growth Hormone levels effect: height in children, increased calcium retention (increase bone mineralization), growth of internal organs, increase protein synthesis, homeostasis maintenance, prevention of hypoglycemia, and stimulates immune function. Increased levels have also been associated with decrease body fat, increased muscle mass, increased bone density, increased energy levels, improved skin tone, and increased sexual function. It’s clear that Growth Hormone is essential, so what can be done to maximize levels (without injections)? Production is effected by stress, exercise, nutrition, and sleep. Sleep probably being the most important of these (we talked about it Tuesday), I can’t emphasize how important sleep is, especially for growing children. For children and adults the most intense period of growth hormone release is just after the onset of deep sleep. The more you sleep the more Growth Hormone you have, whereas the less you sleep the less Growth Hormone you have.Exercise is also a natural stimulate, as is diet (as is important with all aspects of health). Insulin actually inhibits Growth Hormone (another reason not to eat grains, starches and sugars, which spike insulin levels), especially pay attention to what you’re ingesting after a workout. Eating something with a higher glycemic index, actually reduces the hGH effect from the workout that you just did. Eat a low glycemic food and lean protein after exercise to maximize Growth Hormone. Also stay hydrated. Dehydration decreases exercise induced hGH response. Key points for muscle and bone growth (and maintenance): SLEEP, exercise, SLEEP, reduction in insulin intake, SLEEP, and diet.

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