Growth hormone (GH) is a peptide hormone that is intimately involved in tissue growth and repair.  Together with insulin-like growth factor 1 (IGF-1), GH helps regulate metabolism and maintain normal brain and cardiac function.

Secretion of GH falls dramatically with aging, correlating with age-related symptoms such as disordered sleep patterns, fragile bones, cognitive decline, and decreased muscle mass and strength.

Studies examining exogenous GH therapy in elderly adults with declining GH levels have yielded mixed results.

Given the mixed results and the high cost of subcutaneous injection of human recombinant GH therapy, a more natural approach to maintaining youthful health and vigor is to employ lifestyle choices that optimize the endogenous production of GH.

Safe methods for enhancing endogenous GH production include:

• Losing excess body fat, particularly abdominal fat; avoiding high-glycemic load carbohydrates

• Optimizing sleep habits

• Eating a high-protein, low-carbohydrate snack before bedtime

• Exercising regularly to your lactate threshold

• Targeted nutrients including CDP-choline, arginine, ornithine, glycine, glutamine, and niacin (vitamin B3) can help support endogenous GH secretion, assist muscle growth and recovery from exercise, and promote healthy sleep.

Lifestyle Techniques to Naturally Boost Endogenous GH Secretion:

1.   Deflate the spare tire.  If you happen to suffer from fat stores concentrated centrally around the organs of the abdominal region, GH secretion will be even more impaired.  Fortunately, research indicates that declining GH due to body fat gain is partially reversible with weight loss.¹  Unfortunately, visceral adiposity is often an indicator of both insulin and leptin resistance and, as a result, can be very difficult to shed permanently.  Fortunately recent work has led to the discovery of effective, natural methods for combating leptin resistance.^2-4  For more information, see: "Deflating your spare tire for a longer, leaner life . . . Understanding the risks of leptin resistance" Life Extension, February 2009,⁵ and "Vindication" (How correcting a testosterone deficit can reduce abdominal adiposity), Life Extension, December 2008.⁶

2.   Avoid high-glycemic-load carbohydrates.  Insulin is a powerful, direct inhibitor of GH secretion.^7,13  To prevent the unhealthy surges of insulin or "insulin spikes" that decrease endogenous GH levels and increase your risk for type 2 diabetes, avoid highly processed carbohydrates like refined white bread and sugary cereal, as well as high-glycemic-load foods such as white rice, potato chips, cookies, soda, and commercially processed fruit juices (high in fructose and devoid of fiber).  Instead, emphasize nutrient and fiber-rich whole fruits, vegetables, nuts, and legumes (beans).

3.   Insist on a good night's sleep.  The majority of GH secretion occurs at night during slow-wave (deep) sleep.  Along with high-intensity exercise, another natural stimulus of endogenous GH secretion is sleep itself.  It is well documented that inadequate sleep, irregular sleeping patterns, and poor quality sleep can substantially inhibit GH secretion.^13,16  To optimize sleep, maintain good sleep hygiene habits: keep to a regular bedtime and wake-up time; do not consume alcohol or caffeine 4-6 hours before bedtime; and keep excess light and noise out of the bedroom.

4.   Plan your last meal of the day carefully.  Your last meal of the day is the most important for maintaining a robust GH/IGF-1 axis.  A high-protein, low-carbohydrate snack before bedtime serves a dual purpose.  First, it helps minimize insulin release and allows for maximum endogenous GH secretion.  Second, important essential and conditionally essential amino acids found in protein assist endogenous GH secretion.^13-15

5.   Stay active!  Exercise is a significant, natural optimizer of GH secretion.⁹  The type of exercise you do, as well the intensity and duration of your workouts, all play an important role in determining to what degree your training regimen contributes to GH secretion.  A number of studies have suggested that the intensity necessary to trigger exercise-induced GH release corresponds to the lactate threshold -- the exercise intensity at which lactic acid accumulates in the blood.¹⁰  Exercise training above the lactate threshold appears to amplify the pulsatile release of endogenous GH at rest, increasing total secretion for at least 24 hours.¹¹

Declining GH Levels and Poor Health

There are a number of lifestyle factors that lead to decreased GH and IGF-1 secretion.  For example, multiple studies indicate that central adiposity (the accumulation of central body fat) accurately predicts GH decline.^12,17-19 

In addition, it is well established that poor nutritional status, inadequate sleep, and lack of physical fitness can all contribute to decreases in circulating GH and IGF-1, regardless of age.⁷

Individually or in combination, poor nutritional status, inadequate sleep, and lack of physical fitness negatively impact body composition, bone strength, athletic conditioning, and cognition -- independent of their effects on serum GH levels.¹³

It seems clear that an unhealthy lifestyle contributes to somatopause both directly, by causing profound reductions in GH secretion, as well as indirectly, by promoting the physical and psychological symptoms of accelerated aging.

The Life Extension Foundation provided this information on natural ways to increase human growth hormone levels.

Citations:

1.   Williams T, Berelowitz M, Joffe SN, et al.  "Impaired growth hormone responses to growth hormone-releasing factor in obesity. A pituitary defect reversed with weight reduction."  N Engl J Med. 1984 Nov 29;311(22):1403-7.

2.   Ngondi JL, Matsinkou R, Oben JE.  "The use of Irvingia gabonensis extract (IGOB131) in the management of metabolic syndrome in Cameroon." 2008. Submitted for publication.

3.   Oben JE, Ngondi JL, Blum K.  "Inhibition of adipogenesis by Irvingia gabonensis seed extract (IGOB131) as mediated via down regulation of the PPAR gamma and leptin genes, and up-regulation of the adiponectin gene."  Lipids Health Dis. 2008 Nov 13;7(1):44.

4.   Ngondi JL, Djiotsa EJ, Fossouo Z, Oben J.  "Hypoglycaemic effect of the methanol extract of irvingia gabonensis seeds on streptozotocin diabetic rats."  Afr J Trad CAM. 2006;3:74-7.

5.   Lydon C.  "Deflating your spare tire for a longer, leaner life. Turn off your fat switch. Understanding the risks of leptin resistance."  Life Extension. 2009 Feb; 15(2):54-61.

6.   Faloon W.  "Vindication."  Life Extension. 2008 Dec; 14(12):7-14.

7.   Ji S, Guan R, Frank SJ, Messina JL.  "Insulin inhibits growth hormone signaling via the growth hormone receptor/JAK2/STAT5B pathway."  J Biol Chem. 1999 May 7;274(19):13434-42.

8.   Livesey G, Taylor R, Hulshof T, Howlett J.  "Glycemic response and health -- a systematic review and meta-analysis: relations between dietary glycemic properties and health outcomes."  Am J Clin Nutr. 2008 Jan;87(1):258S-268S.

9.   Ftaiti F, Jemni M, Kacem A, et al.  "Effect of hyperthermia and physical activity on circulating growth hormone."  Appl Physiol Nutr Metab. 2008 Oct;33(5):880-7.

10.   Godfrey RJ, Whyte GR, Buckley J, Quinlivan R.  "The role of lactate in the exercise-induced human growth hormone response: evidence from McArdle's disease."  Br J Sports Med. 2008 Jan 31.

11.   Godfrey RJ, Madgwick Z, Whyte GP.  "The exercise-induced growth hormone response in athletes."  Sports Med. 2003;33(8):599-613.

12.   Vahl N, Jorgensen JO, Jurik AG, Christiansen JS.  "Abdominal adiposity and physical fitness are major determinants of the age associated decline in stimulated GH secretion in healthy adults."  J Clin Endocrinol Metab. 1996 Jun;81(6):2209-15.

13.   Available at:  http://www.endotext.org/neuroendo/neuroendo5c/neuroendoframe5c.htm.  Accessed December 30, 2008.

14.   Chromiak JA, Antonio J.  "Use of amino acids as growth hormone-releasing agents by athletes."  Nutrition. 2002 Jul;18(7-8):657-61.

15.   Adriao M, Chrisman CJ, Bielavsky M, et al.  "Arginine increases growth hormone gene expression in rat pituitary and GH3 cells."  Neuroendocrinology. 2004 Jan;79(1):26-33.

16.   Available at:  http://emedicine.medscape.com/article/126999-overview.  Accessed January 5, 2009.

17.   Vahl N, Jorgensen JO, Skjaerbaek C, et al.  "Abdominal adiposity rather than age and sex predicts mass and regularity of GH secretion in healthy adults."  Am J Physiol. 1997 Jun;272(6 Pt 1):E1108-16.

18.   Scacchi M, Pincelli AI, Cavagnini F.  "Growth hormone in obesity."  Int J Obes Relat Metab Disord. 1999 Mar;23(3):260-71.

19.   Savastano S, Di Somma C, Belfiore A, et al.  "Growth hormone status in morbidly obese subjects and correlation with body composition."  J Endocrinol Invest. 2006 Jun;29(6):536-43.