The influence of human growth hormone (HGH) on physiologic processes and exercise: Difference between revisions

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= '''[[Image:HGH function.jpg|right|248x304px]]Introduction'''<br>  =
= '''[[Image:HGH function.jpg|right|248x304px]]Introduction'''<br>  =


Human growth hormone (HGH), also known as somatotropin, is peptide hormone secreted by the anterior pituitary gland <ref name="Hoffman">Hoffman, J.R., Kraemer, W. J., Bhasin, S., Storer, T., Ratamess, N. A., Haff, G. G., Willoughby, D. S. Rogol, A. D. (2009). Position stand on androgen and human growth hormone use. Journal of Strength and Conditioning Research, 23(5), S1-S59. Doi: 10. 1519/JSC. 0b013e31819df2e6</ref>. HGH is an anabolic hormone that builds and repairs tissue, such as collagen and muscle tissue, throughout the body<ref name="Hoffman" />. HGH release is stimulated from the release of growth hormone releasing hormone (GHRH), which is released as a result of exercise<ref name="Kraemer">Kraemer, W. J., Dunn-Lewis, C., Comstock, B. A., Thomas, G. A., Clark, J. E.,&amp;amp;amp;amp;amp;amp;amp;amp; Nindl, B. C. (2010). Growth hormone, exercise, and athletic performance: A continued evolution of complexity. Current Sports Medicine Reports, 9(4), 242. doi:10.1249/JSR.0b013e3181e976df</ref>. HGH promotes the release of IGF-1, which promotes anabolic effects within the body<ref name="Kraemer" /> .It also helps facilitate body's response to exercise, however it's effects are not restricted to protein alone.<ref name="Kraemer" /> HGH is only released periodically, such as during certain stages of sleep, certain parts of the day, and with exercise <ref name="Kraemer" />.It has been shown that the menstrual cycle and oral contraceptive use have a significant impact on growth hormone levels <ref>Sunderland, C., Tunaley, V., Horner, F., Harmer, D., Stokes, K. A. (2011). Menstrual cycle and oral contraceptives’ effects on growth hormone response to sprinting. Journal of Applied Physiology, Nutrition, and Metabolism, 36(4), 495-502.</ref>. The periodic release of HGH combined with its positive anabolic and metabolic effects on the body has lead to supplementation of HGH to improve exercise performance.  
Human growth hormone (HGH), also known as somatotropin, is a peptide hormone secreted by the anterior pituitary gland <ref name="Hoffman">Hoffman, J.R., Kraemer, W. J., Bhasin, S., Storer, T., Ratamess, N. A., Haff, G. G., Willoughby, D. S. Rogol, A. D. (2009). Position stand on androgen and human growth hormone use. Journal of Strength and Conditioning Research, 23(5), S1-S59. Doi: 10. 1519/JSC. 0b013e31819df2e6</ref>. HGH is an anabolic hormone that builds and repairs tissue, such as collagen and muscle tissue, throughout the body<ref name="Hoffman" />. HGH release is stimulated from the release of growth hormone releasing hormone (GHRH), which is released as a result of exercise<ref name="Kraemer">Kraemer, W. J., Dunn-Lewis, C., Comstock, B. A., Thomas, G. A., Clark, J. E.,&amp;amp;amp;amp;amp;amp;amp;amp;amp; Nindl, B. C. (2010). Growth hormone, exercise, and athletic performance: A continued evolution of complexity. Current Sports Medicine Reports, 9(4), 242. doi:10.1249/JSR.0b013e3181e976df</ref>. HGH promotes the release of IGF-1, which promotes anabolic effects within the body<ref name="Kraemer" /> .It also helps facilitate the body's response to exercise. However, it's effects are not restricted to protein alone.<ref name="Kraemer" /> HGH is only released periodically, such as during certain stages of sleep, certain parts of the day, and with exercise <ref name="Kraemer" />.It has been shown that the menstrual cycle and oral contraceptive use have a significant impact on growth hormone levels <ref>Sunderland, C., Tunaley, V., Horner, F., Harmer, D., Stokes, K. A. (2011). Menstrual cycle and oral contraceptives’ effects on growth hormone response to sprinting. Journal of Applied Physiology, Nutrition, and Metabolism, 36(4), 495-502.</ref>. The periodic release of HGH combined with its positive anabolic and metabolic effects on the body has lead to supplementation of HGH to improve exercise performance.  


= '''Musculoskeletal'''  =
= '''Musculoskeletal'''  =


HGH is an important component of metabolism by increasing lean body mass and promoting lipolysis<ref>Hoffman, J.R., Kraemer, W. J., Bhasin, S., Storer, T., Ratamess, N. A., Haff, G. G., Willoughby, D. S. &amp;amp;amp;amp;amp;amp;amp; Rogol, A. D. (2009). Position stand on androgen and human growth hormone use. Journal of Strength and Conditioning Research, 23(5), S1-S59. Doi: 10. 1519/JSC. 0b013e31819df2e6</ref> . Growth Hormone also increases synthesis of muscle protein via amino acid transport and amino acid availibility<ref>Kraemer, W. J., Dunn-Lewis, C., Comstock, B. A., Thomas, G. A., Clark, J. E. &amp;amp;amp;amp;amp;amp;amp; Nindl, B. C. (2010). Growth hormone, exercise, and athletic performance: A continued evolution of complexity. Current Sports Medicine Reports, 9(4), 242-252. Doi: 10. 1249/JSR. 0b013e3181e976df</ref>.&nbsp;This&nbsp;hormone that is naturally produced&nbsp;by&nbsp;the body&nbsp;is&nbsp;used in various&nbsp;forms&nbsp;for athletic improvement, hormone defiencies, and other muculoskeletal conditions&nbsp;in diverse patient populations.  
HGH is an important component of metabolism because it increases lean body mass and promotes lipolysis<ref>Hoffman, J.R., Kraemer, W. J., Bhasin, S., Storer, T., Ratamess, N. A., Haff, G. G., Willoughby, D. S. &amp;amp;amp;amp;amp;amp;amp;amp; Rogol, A. D. (2009). Position stand on androgen and human growth hormone use. Journal of Strength and Conditioning Research, 23(5), S1-S59. Doi: 10. 1519/JSC. 0b013e31819df2e6</ref> . Human Growth Hormone also increases synthesis of muscle protein via amino acid transport and amino acid availibility<ref>Kraemer, W. J., Dunn-Lewis, C., Comstock, B. A., Thomas, G. A., Clark, J. E. &amp;amp;amp;amp;amp;amp;amp;amp; Nindl, B. C. (2010). Growth hormone, exercise, and athletic performance: A continued evolution of complexity. Current Sports Medicine Reports, 9(4), 242-252. Doi: 10. 1249/JSR. 0b013e3181e976df</ref>.&nbsp;This&nbsp;hormone, that is naturally produced&nbsp;by&nbsp;the body, is&nbsp;used in various&nbsp;forms&nbsp;for athletic improvement, hormone defiencies, and other muculoskeletal conditions&nbsp;in diverse patient populations.  


== Athletes  ==
== Athletes  ==


HGH injections and supplements are widely abused by athletes to enhance performance. Nevertheless, there is not enough definititive evidence that HGH improves performance<ref>Saugy, M., Robinson, N., Saudan, C., Baume, N., Avois, L., Mahgin, P. (2006). Human growth hormone doping in sport. British Journal of Sports Medicine, 40, 135-139.</ref> Meinhardt et al. (2010) examines the effect of a 2mg dose of HGH on body composition, endurance, strength, power, and sprint capacity.&nbsp; The study uses recreationally active men and women in randomized control trails <ref name="Meinhardt">Meinhardt, U., Nelson, A. E., Hansen, J. L., Birzniece, V., Clifford, D., Leung, K., . . . Ho, K. K.(2010). The effects of growth hormone on body composition and performance in recreational athletes. Annals of Internal Medicine, 152, 568-577.</ref>.&nbsp; The results show increases in muslce mass and decreases in fat mass. Sprint capacity showed increases but the results were small making it difficult to determine if HGH contributes to sprint performance. The increase in sprint capacity was not maintained after six weeks of discontiuation of HGH<ref name="Meinhardt" />. Endurance, strength, and power show no significant changes with HGH supplementation.&nbsp; Meinhardt et al. (2010) argues that growth hormone injections increase athletic exercise performance when given alone or with testosterone. In addition, participants that received growth hormones retained more body fluid and frequent joint pain than control group<ref name="Meinhardt" />.  
HGH injections and supplements are widely abused by athletes to enhance performance. Nevertheless, there is not enough definititive evidence that HGH improves performance<ref>Saugy, M., Robinson, N., Saudan, C., Baume, N., Avois, L., Mahgin, P. (2006). Human growth hormone doping in sport. British Journal of Sports Medicine, 40, 135-139.</ref> Meinhardt et al. (2010) examines the effect of a 2mg dose of HGH on body composition, endurance, strength, power, and sprint capacity.&nbsp; The study uses recreationally active men and women in randomized control trials <ref name="Meinhardt">Meinhardt, U., Nelson, A. E., Hansen, J. L., Birzniece, V., Clifford, D., Leung, K., . . . Ho, K. K.(2010). The effects of growth hormone on body composition and performance in recreational athletes. Annals of Internal Medicine, 152, 568-577.</ref>.&nbsp; The results show increases in muslce mass and decreases in fat mass. Sprint capacity showed increases, but the results were small making it difficult to determine if HGH contributes to sprint performance. The increase in sprint capacity was not maintained after six weeks of discontiuation of HGH<ref name="Meinhardt" />. Endurance, strength, and power show no significant changes with HGH supplementation.&nbsp; Meinhardt et al. (2010) argues that growth hormone injections increase athletic exercise performance when given alone or with testosterone. In addition, participants that received growth hormones retained more body fluid and had more frequent joint pain than the control group<ref name="Meinhardt" />.  


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HGH supplementation usage amoung athletes is to improve body composition in both men and women. HGH increases lean body mass and decreases fat mass, but there is little research to support that HGH contributes to increases in strength, power, or endurance.&nbsp; HGH is currently banned by WADA due to its ability to increase muscle mass and potential to increase athletic performance<ref name="Reardon">Reardon, C. L., &amp;amp;amp; Creado, S. (2014). Drug abuse in athletes. Substance Abuse and Rehabilitation, 5, 95-105. doi:  10.2147/SAR.S53784</ref>.  
HGH supplement usage among athletes is to improve body composition in both men and women. HGH increases lean body mass and decreases fat mass, but there is little research to support that HGH contributes to increases in strength, power, or endurance.&nbsp; HGH is currently banned by WADA due to its ability to increase muscle mass and potential to increase athletic performance<ref name="Reardon">Reardon, C. L., &amp;amp;amp;amp; Creado, S. (2014). Drug abuse in athletes. Substance Abuse and Rehabilitation, 5, 95-105. doi:  10.2147/SAR.S53784</ref>.  


== Older Adults  ==
== Older Adults  ==


HGH injections are not only used for athletes, but for the older population as well. One study analyzed the impact of recombinant human growth hormones and testosterone injections on aerobic and anaerobic fitness, body mass, and lipid profile in adult men <ref>Zajac, A., Wilk, M., Socha, T., Maszczyk, A., and Chycki, J. (2014). Effects of growth hormone and fckLRtestosterone therapy on aerobic and anaerobic fitness, body composition and lipoprotein profile in middle-aged men. Annal of Agricultural and Environmental Medicine, 21(1), 156-160.</ref>. The data demonstrates that recombinant human growth hormones and testosterone injections significantly increased aerobic and anaerobic capacity, led to changes in body compositions, and decreased total body fat and increased free-fat muscle. In another study, the authors analyzed whether treatment with testosterone and recombinant human growth hormones would increase muscle strength and mass in older adult patients<ref>Schroeder, E. T., He, J., Yarasheski, K. E., Binder, E. F., Castaneda-Sceppa, C., Bhasin, S., . . . Sattler, F. R. (2011). Value of measuring muscle performance to assess changes in lean mass with testosterone and growth hormone supplementation. Europe Journal of Applied Physiology, 112, 1123-1131.</ref>. The authors found that recombinant human growth hormones are connected with fluid preservation and improvements in muscle mass and strength that would translate into better aerobic exercise performance. &nbsp;  
HGH injections are not only used for athletes but for the older population as well. One study analyzed the impact of recombinant human growth hormones and testosterone injections on aerobic and anaerobic fitness, body mass, and lipid profile in adult men <ref>Zajac, A., Wilk, M., Socha, T., Maszczyk, A., and Chycki, J. (2014). Effects of growth hormone and fckLRtestosterone therapy on aerobic and anaerobic fitness, body composition and lipoprotein profile in middle-aged men. Annal of Agricultural and Environmental Medicine, 21(1), 156-160.</ref>. The data demonstrates that recombinant human growth hormones and testosterone injections significantly increased aerobic and anaerobic capacity, led to changes in body compositions, and decreased total body fat and increased free-fat muscle. In another study, the authors analyzed whether treatment with testosterone and recombinant human growth hormones would increase muscle strength and mass in older adult patients<ref>Schroeder, E. T., He, J., Yarasheski, K. E., Binder, E. F., Castaneda-Sceppa, C., Bhasin, S., . . . Sattler, F. R. (2011). Value of measuring muscle performance to assess changes in lean mass with testosterone and growth hormone supplementation. Europe Journal of Applied Physiology, 112, 1123-1131.</ref>. The authors found that recombinant human growth hormones are connected with fluid preservation and improvements in muscle mass and strength that would translate into better aerobic exercise performance. &nbsp;  


== Exercise Prescription<br>  ==
== Exercise Prescription<br>  ==


Although HGH injections are one of the most common forms of HGH found in the body, the body can naturally produce HGH through certain exercise. An article by Maresh et. al compared two different exercise routines between men and women in order to determine which exercise caused the greatest change in the amount of serum glucose and blood lactate levels within the body as a direct result of the different exercises. This study found that a heavy resistance exercise protocol (HREP) of high volume, 10RM load, and shorter rest periods produced a drastic stimulus of serum hGH levels within the body, while a lower volume and a longer rest period produced and clearer and more sustained elevaton of hGH levels <ref>Maresh, C., &amp;amp;amp; Fry, A. C. (1991). Endogenous anabolic hormonal and growth factor responses to heavy resistance exercise in males and females. Int. J. SportsMed, 12, 228-235.</ref>. Knowing this, physical therapists should consider volume, repetitions, and rest periods when prescribing exercise for various patients based off the goals set forth between the therapist and the patient.&nbsp;  
Although HGH injections are one of the most common forms of HGH found in the body, the body can naturally produce HGH through certain exercise. An article by Maresh et. al compared two different exercise routines between men and women in order to determine which exercise caused the greatest change in the amount of serum glucose and blood lactate levels within the body as a direct result of the different exercises. This study found that a heavy resistance exercise protocol (HREP) of high volume, 10RM load, and shorter rest periods produced a drastic stimulus of serum hGH levels within the body, while a lower volume and a longer rest period produced and clearer and more sustained elevaton of HGH levels <ref>Maresh, C., &amp;amp;amp;amp; Fry, A. C. (1991). Endogenous anabolic hormonal and growth factor responses to heavy resistance exercise in males and females. Int. J. SportsMed, 12, 228-235.</ref>. Knowing this, physical therapists should consider volume, repetitions, and rest periods when prescribing exercise for various patients based off the goals set forth between the therapist and the patient.&nbsp;  


== Side Effects&nbsp;  ==
== Side Effects&nbsp;  ==


There are serveral side effects seen when supplementing HGH. According to findings in the systematic review by Liu et al. (2008) these side effects include sweating, joint pain, swelling, and possibly carpal tunnel syndrome <ref>Liu, H., Bravata, D. M., Olkin, I., Friedlander, A., Liu, V., Roberts, B., …Hoffman, A. R. (2008). Systematic review: The effects of growth hormone on athletic performance. Annals of Internal Medicine, 148(10), 747-758. doi: 10. 7326/0003-4819-148-10-200805200-00215</ref>. Other side effects of concern include risk of diabetes in elderly populations because of the elevation of glucose in the blood it causes <ref>Kraemer, W. J., Dunn-Lewis, C., Comstock, B. A., Thomas, G. A., Clark, J. E., &amp; Nindl, B. C. (2010). Growth hormone, exercise, and athletic performance: A continued evolution of complexity. Current Sports Medicine Reports, 9(4), 242. doi:10.1249/JSR.0b013e3181e976df</ref>. Long term saftey of HGH supplemetation is still under investigation, but preliminary studies on mice show that there is not an increased risk to survival, longevity, or tumor development, but it is unknown if these findings will transfer to humans <ref>Kraemer, W. J., Dunn-Lewis, C., Comstock, B. A., Thomas, G. A., Clark, J. E., &amp; Nindl, B. C. (2010). Growth hormone, exercise, and athletic performance: A continued evolution of complexity. Current Sports Medicine Reports, 9(4), 242. doi:10.1249/JSR.0b013e3181e976df</ref>. High doses of HGH supplemetation can cause functionally weaker muscles depsite increases in hypertophy. Consistantly high levels of GH may also result in hypertension, cardiac, and metabolic complications <ref>Birzniece, V., Nelson, A. E., Ho, K. K. Y. (2011). Growth hormone and physical performance. Trends in Endocrinology &amp; Metabolism, 22(5), 171-178. doi:10.1016/j.tem.2011.02.005</ref>. Abuse of Growth Hormone can cause significant health risks when taken with other drugs <ref>Birzniece, V., Nelson, A. E., &amp; Ho, K. K. Y. (2011). Growth hormone and physical performance. Trends in Endocrinology &amp; Metabolism, 22(5), 171-178. doi:10.1016/j.tem.2011.02.005</ref>. Unfortunately, the extent of these health risks are unknown because of ethical delemas in doing studies on drug abuse. Despite these negative side effects, HGH is still one of the most commonly abused drugs especially among athletes and atheltic populations. <br>
There are serveral side effects seen when supplementing HGH. According to findings in the systematic review by Liu et al. (2008) these side effects include sweating, joint pain, swelling, and possibly carpal tunnel syndrome <ref>Liu, H., Bravata, D. M., Olkin, I., Friedlander, A., Liu, V., Roberts, B., …Hoffman, A. R. (2008). Systematic review: The effects of growth hormone on athletic performance. Annals of Internal Medicine, 148(10), 747-758. doi: 10. 7326/0003-4819-148-10-200805200-00215</ref>. Other side effects of concern include risk of diabetes in elderly populations because it causes elevation of blood glucose levels&nbsp;<ref>Kraemer, W. J., Dunn-Lewis, C., Comstock, B. A., Thomas, G. A., Clark, J. E., &amp;amp; Nindl, B. C. (2010). Growth hormone, exercise, and athletic performance: A continued evolution of complexity. Current Sports Medicine Reports, 9(4), 242. doi:10.1249/JSR.0b013e3181e976df</ref>. Long term saftey of HGH supplemetation is still under investigation, but preliminary studies on mice show that there is not an increased risk to survival, longevity, or tumor development, but it is unknown if these findings will transfer to humans <ref>Kraemer, W. J., Dunn-Lewis, C., Comstock, B. A., Thomas, G. A., Clark, J. E., &amp;amp; Nindl, B. C. (2010). Growth hormone, exercise, and athletic performance: A continued evolution of complexity. Current Sports Medicine Reports, 9(4), 242. doi:10.1249/JSR.0b013e3181e976df</ref>. High doses of HGH supplemetation can cause functionally weaker muscles depsite increases in hypertophy. Consistently high levels of GH may also result in hypertension, cardiac, and metabolic complications <ref>Birzniece, V., Nelson, A. E., Ho, K. K. Y. (2011). Growth hormone and physical performance. Trends in Endocrinology &amp;amp; Metabolism, 22(5), 171-178. doi:10.1016/j.tem.2011.02.005</ref>. Abuse of Human Growth Hormone can cause significant health risks when taken with other drugs <ref>Birzniece, V., Nelson, A. E., &amp;amp; Ho, K. K. Y. (2011). Growth hormone and physical performance. Trends in Endocrinology &amp;amp; Metabolism, 22(5), 171-178. doi:10.1016/j.tem.2011.02.005</ref>. Unfortunately, the extent of these health risks are unknown because of ethical dilemmas in doing studies on drug abuse. Despite these negative side effects, HGH is still one of the most commonly abused drugs, especially among athletes and atheltic populations. <br>  


= References  =
= References  =

Revision as of 19:13, 1 December 2015

HGH function.jpg
Introduction
[edit | edit source]

Human growth hormone (HGH), also known as somatotropin, is a peptide hormone secreted by the anterior pituitary gland [1]. HGH is an anabolic hormone that builds and repairs tissue, such as collagen and muscle tissue, throughout the body[1]. HGH release is stimulated from the release of growth hormone releasing hormone (GHRH), which is released as a result of exercise[2]. HGH promotes the release of IGF-1, which promotes anabolic effects within the body[2] .It also helps facilitate the body's response to exercise. However, it's effects are not restricted to protein alone.[2] HGH is only released periodically, such as during certain stages of sleep, certain parts of the day, and with exercise [2].It has been shown that the menstrual cycle and oral contraceptive use have a significant impact on growth hormone levels [3]. The periodic release of HGH combined with its positive anabolic and metabolic effects on the body has lead to supplementation of HGH to improve exercise performance.

Musculoskeletal[edit | edit source]

HGH is an important component of metabolism because it increases lean body mass and promotes lipolysis[4] . Human Growth Hormone also increases synthesis of muscle protein via amino acid transport and amino acid availibility[5]. This hormone, that is naturally produced by the body, is used in various forms for athletic improvement, hormone defiencies, and other muculoskeletal conditions in diverse patient populations.

Athletes[edit | edit source]

HGH injections and supplements are widely abused by athletes to enhance performance. Nevertheless, there is not enough definititive evidence that HGH improves performance[6] Meinhardt et al. (2010) examines the effect of a 2mg dose of HGH on body composition, endurance, strength, power, and sprint capacity.  The study uses recreationally active men and women in randomized control trials [7].  The results show increases in muslce mass and decreases in fat mass. Sprint capacity showed increases, but the results were small making it difficult to determine if HGH contributes to sprint performance. The increase in sprint capacity was not maintained after six weeks of discontiuation of HGH[7]. Endurance, strength, and power show no significant changes with HGH supplementation.  Meinhardt et al. (2010) argues that growth hormone injections increase athletic exercise performance when given alone or with testosterone. In addition, participants that received growth hormones retained more body fluid and had more frequent joint pain than the control group[7].


Liu et al. (2008) conducted a systematic review to explore the effects of growth hormone on athletic performance. The results include an increase in lean body mass and basal metabolic rate after HGH supplementation. The study shows why athetes use HGH as a means to improving body composition [8] . The increase in lean mass often leads to increases in metabolism, due to the increased need to build and repair the lean tissue. The study did not find any significant increases in muscular strength or improvement in aerobic exercise [8] .


HGH supplement usage among athletes is to improve body composition in both men and women. HGH increases lean body mass and decreases fat mass, but there is little research to support that HGH contributes to increases in strength, power, or endurance.  HGH is currently banned by WADA due to its ability to increase muscle mass and potential to increase athletic performance[9].

Older Adults[edit | edit source]

HGH injections are not only used for athletes but for the older population as well. One study analyzed the impact of recombinant human growth hormones and testosterone injections on aerobic and anaerobic fitness, body mass, and lipid profile in adult men [10]. The data demonstrates that recombinant human growth hormones and testosterone injections significantly increased aerobic and anaerobic capacity, led to changes in body compositions, and decreased total body fat and increased free-fat muscle. In another study, the authors analyzed whether treatment with testosterone and recombinant human growth hormones would increase muscle strength and mass in older adult patients[11]. The authors found that recombinant human growth hormones are connected with fluid preservation and improvements in muscle mass and strength that would translate into better aerobic exercise performance.  

Exercise Prescription
[edit | edit source]

Although HGH injections are one of the most common forms of HGH found in the body, the body can naturally produce HGH through certain exercise. An article by Maresh et. al compared two different exercise routines between men and women in order to determine which exercise caused the greatest change in the amount of serum glucose and blood lactate levels within the body as a direct result of the different exercises. This study found that a heavy resistance exercise protocol (HREP) of high volume, 10RM load, and shorter rest periods produced a drastic stimulus of serum hGH levels within the body, while a lower volume and a longer rest period produced and clearer and more sustained elevaton of HGH levels [12]. Knowing this, physical therapists should consider volume, repetitions, and rest periods when prescribing exercise for various patients based off the goals set forth between the therapist and the patient. 

Side Effects [edit | edit source]

There are serveral side effects seen when supplementing HGH. According to findings in the systematic review by Liu et al. (2008) these side effects include sweating, joint pain, swelling, and possibly carpal tunnel syndrome [13]. Other side effects of concern include risk of diabetes in elderly populations because it causes elevation of blood glucose levels [14]. Long term saftey of HGH supplemetation is still under investigation, but preliminary studies on mice show that there is not an increased risk to survival, longevity, or tumor development, but it is unknown if these findings will transfer to humans [15]. High doses of HGH supplemetation can cause functionally weaker muscles depsite increases in hypertophy. Consistently high levels of GH may also result in hypertension, cardiac, and metabolic complications [16]. Abuse of Human Growth Hormone can cause significant health risks when taken with other drugs [17]. Unfortunately, the extent of these health risks are unknown because of ethical dilemmas in doing studies on drug abuse. Despite these negative side effects, HGH is still one of the most commonly abused drugs, especially among athletes and atheltic populations.

References[edit | edit source]

  1. ↑ 1.0 1.1 Hoffman, J.R., Kraemer, W. J., Bhasin, S., Storer, T., Ratamess, N. A., Haff, G. G., Willoughby, D. S. Rogol, A. D. (2009). Position stand on androgen and human growth hormone use. Journal of Strength and Conditioning Research, 23(5), S1-S59. Doi: 10. 1519/JSC. 0b013e31819df2e6
  2. ↑ 2.0 2.1 2.2 2.3 Kraemer, W. J., Dunn-Lewis, C., Comstock, B. A., Thomas, G. A., Clark, J. E.,&amp;amp;amp;amp;amp;amp;amp;amp; Nindl, B. C. (2010). Growth hormone, exercise, and athletic performance: A continued evolution of complexity. Current Sports Medicine Reports, 9(4), 242. doi:10.1249/JSR.0b013e3181e976df
  3. ↑ Sunderland, C., Tunaley, V., Horner, F., Harmer, D., Stokes, K. A. (2011). Menstrual cycle and oral contraceptives’ effects on growth hormone response to sprinting. Journal of Applied Physiology, Nutrition, and Metabolism, 36(4), 495-502.
  4. ↑ Hoffman, J.R., Kraemer, W. J., Bhasin, S., Storer, T., Ratamess, N. A., Haff, G. G., Willoughby, D. S. &amp;amp;amp;amp;amp;amp;amp; Rogol, A. D. (2009). Position stand on androgen and human growth hormone use. Journal of Strength and Conditioning Research, 23(5), S1-S59. Doi: 10. 1519/JSC. 0b013e31819df2e6
  5. ↑ Kraemer, W. J., Dunn-Lewis, C., Comstock, B. A., Thomas, G. A., Clark, J. E. &amp;amp;amp;amp;amp;amp;amp; Nindl, B. C. (2010). Growth hormone, exercise, and athletic performance: A continued evolution of complexity. Current Sports Medicine Reports, 9(4), 242-252. Doi: 10. 1249/JSR. 0b013e3181e976df
  6. ↑ Saugy, M., Robinson, N., Saudan, C., Baume, N., Avois, L., Mahgin, P. (2006). Human growth hormone doping in sport. British Journal of Sports Medicine, 40, 135-139.
  7. ↑ 7.0 7.1 7.2 Meinhardt, U., Nelson, A. E., Hansen, J. L., Birzniece, V., Clifford, D., Leung, K., . . . Ho, K. K.(2010). The effects of growth hormone on body composition and performance in recreational athletes. Annals of Internal Medicine, 152, 568-577.
  8. ↑ 8.0 8.1 Liu, H., Bravata, D. M., Olkin, I., Friedlander, A., Liu, V., Roberts, B. … Hoffman, A. R. (2008). Systematic review: The effects of growth hormone on athletic performance. Annals of Internal Medicine, 148(10), 747-758. doi: 10. 7326/0003-4819-148-10-200805200-00215
  9. ↑ Reardon, C. L., &amp;amp;amp; Creado, S. (2014). Drug abuse in athletes. Substance Abuse and Rehabilitation, 5, 95-105. doi: 10.2147/SAR.S53784
  10. ↑ Zajac, A., Wilk, M., Socha, T., Maszczyk, A., and Chycki, J. (2014). Effects of growth hormone and fckLRtestosterone therapy on aerobic and anaerobic fitness, body composition and lipoprotein profile in middle-aged men. Annal of Agricultural and Environmental Medicine, 21(1), 156-160.
  11. ↑ Schroeder, E. T., He, J., Yarasheski, K. E., Binder, E. F., Castaneda-Sceppa, C., Bhasin, S., . . . Sattler, F. R. (2011). Value of measuring muscle performance to assess changes in lean mass with testosterone and growth hormone supplementation. Europe Journal of Applied Physiology, 112, 1123-1131.
  12. ↑ Maresh, C., &amp;amp;amp; Fry, A. C. (1991). Endogenous anabolic hormonal and growth factor responses to heavy resistance exercise in males and females. Int. J. SportsMed, 12, 228-235.
  13. ↑ Liu, H., Bravata, D. M., Olkin, I., Friedlander, A., Liu, V., Roberts, B., …Hoffman, A. R. (2008). Systematic review: The effects of growth hormone on athletic performance. Annals of Internal Medicine, 148(10), 747-758. doi: 10. 7326/0003-4819-148-10-200805200-00215
  14. ↑ Kraemer, W. J., Dunn-Lewis, C., Comstock, B. A., Thomas, G. A., Clark, J. E., &amp; Nindl, B. C. (2010). Growth hormone, exercise, and athletic performance: A continued evolution of complexity. Current Sports Medicine Reports, 9(4), 242. doi:10.1249/JSR.0b013e3181e976df
  15. ↑ Kraemer, W. J., Dunn-Lewis, C., Comstock, B. A., Thomas, G. A., Clark, J. E., &amp; Nindl, B. C. (2010). Growth hormone, exercise, and athletic performance: A continued evolution of complexity. Current Sports Medicine Reports, 9(4), 242. doi:10.1249/JSR.0b013e3181e976df
  16. ↑ Birzniece, V., Nelson, A. E., Ho, K. K. Y. (2011). Growth hormone and physical performance. Trends in Endocrinology &amp; Metabolism, 22(5), 171-178. doi:10.1016/j.tem.2011.02.005
  17. ↑ Birzniece, V., Nelson, A. E., &amp; Ho, K. K. Y. (2011). Growth hormone and physical performance. Trends in Endocrinology &amp; Metabolism, 22(5), 171-178. doi:10.1016/j.tem.2011.02.005
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