Exercise and androgen levels

Last updated

Physical exercise has been found to be associated with changes in androgen levels. In cross-sectional analyses, aerobic exercisers have lower basal total and free testosterone compared to the sedentary. [1] [2] [3] [4] Anaerobic exercisers also have lower testosterone compared to the sedentary [1] but a slight increase in basal testosterone with resistance training over time. [5] There is some correlation between testosterone and physical activity in the middle aged and elderly. [6] Acutely, testosterone briefly increases when comparing aerobic, anaerobic and mixed forms of exercise. [7] A study assessed men who were resistance trained, endurance trained, or sedentary in which they either rested, ran or did a resistance session. Androgens increased in response to exercise, particularly resistance, while cortisol only increased with resistance. DHEA increased with resistance exercise and remained elevated during recovery in resistance-trained subjects. After initial post-exercise increase, there was decline in free and total testosterone during resistance recovery, particularly in resistance-trained subjects. Endurance-trained subjects showed less change in hormone levels in response to exercise than resistance-trained subjects. [8] Another study found relative short term effects of aerobic, anaerobic and combined anaerobic-aerobic exercise protocols on hormone levels did not change. The study noted increases in testosterone and cortisol immediately after exercise, which in 2 hours returned to baseline levels. [9]

Contents

Aerobic

In trained long term aerobic exercisers, basal levels are unchanged, [10] or decreased. [9] [11] Acutely, endurance based aerobic efforts cause testosterone to rise. [12]

A year long, moderate-intensity aerobic exercise program increased DHT and SHBG in sedentary men age 40–75, but had no effect on other androgens. Both DHT and SHBG increased 14% in exercisers at 3 months, and at 12 months they remained 9% above baseline. SHBG is protective against DHT as it binds free androgen. [13] In acute assessment of hormone levels in soccer players before, during and after a game, DHT and testosterone increased during the match, but returned to baseline after 45 minutes rest. [14] Aerobic exercise in Japanese rats done on a rodent treadmill doubled local concentrations of DHT in calf muscles as assessed by protein assay. [15] After intense aerobic effort, high endurance athletes were also found to have lower free testosterone the next day. [16] In prolonged endurance exercise, such as a marathon, levels ultimately decrease. [17] Similarly, DHT drops, while adrenal androgen and cortisol will increase with the stress response. [18]

Anaerobic

Effects of anaerobic exercise also vary with length of time. TwoDumbbells.JPG
Effects of anaerobic exercise also vary with length of time.

It is unknown if anaerobic training changes individual hormone profiles, or if conditioned athletes in studies self-selected because of physiologic predisposition to athletic conditioning. [19] There is variation of response to anaerobic stress depending on exercise intensity, age, gender, length of time studied, and time at which serum indices were drawn. Most studies report that testosterone increases or is unchanged acutely, though some even report it to decrease. Anaerobic exercisers have testosterone levels below sedentary controls in cross sectional analysis. Over months to years, levels are stable to slightly increased.

The ratio of testosterone to cortisol can both increase [20] and decrease [21] during resistance training, depending on intensity of exercise. A study comparing young and old subjects showed acute increases in GH and testosterone for both, although the latter increased less in older men. [22] Testosterone rises in late hours of sleep after anaerobic exercise. [23] Skeletal muscle androgen receptor expression increases with acute exercise in correlation to free testosterone. [24] When comparing men and women in the 30-, 50-, and 70-year age groups, young and middle aged men showed increased testosterone after exercise, with the latter also having increased cortisol. Elderly men showed no change. [25] Other studies have also shown with age there is a downtrend of testosterone [26] and attenuated growth hormone response. [27] Young men have shown no acute change in testosterone with resistance training, with increase in cortisol and growth hormone depending on intensity. [28] One study in young men showed testosterone acutely stable, with increase in GH and IGF-1. [29] Similarly, a study showed testosterone did not increase in young men, women, and pubescent boys unaccustomed to weight training when corrected for plasma volume. [30] Extreme intensity of strength training may trigger the stress response, resulting in lower testosterone levels, [31] an effect accentuated by energy deprivation. [32]

A separate study comparing different ages, however, found no difference in acute testosterone and cortisol levels between groups, but attenuated growth hormone response in the elderly. [27] Acutely, other studies have shown testosterone to increase. [33] In a small group of anaerobically trained athletes, stressful training acutely even decreased serum testosterone and its ratio to cortisol and SHBG, with an increase in LH. With subsequent decompensation, testosterone was stable, but cortisol and SHBG decreased. [21] Another case control showed with intense training followed by rest, testosterone dropped and LH increased initially. [34]

Interval and quality of exercise also affect hormonal response. Sessions of moderate to high intensity with multiple sets and short time intervals, during which energy is derived from glycolytic lactate metabolism, appear to be the greatest stimulus for steroid hormone response. Hormonal response in young men varies with the number of sets in the exercise session. However, when the number increased from 4 to 6, anabolic levels stabilized and cortisol continued to rise, suggesting that alterations in anaerobic volume could alter anabolic and catabolic hormonal balance. [28] When sets are performed at maximum repetitions, interval has no influence at a certain intensity range, with no acute hormone response difference between protocols at 10 maximum reps with 2- and 5-minute intervals. [35] There is a higher total testosterone response in hypertrophy protocols compared to those for strength and power, despite equalization of total work load (defined as load x sets x repetitions). [36] There is a 27% greater testosterone response using protocols with simultaneous use of all four limbs. Androgenic response was also noted in protocols using upper and lower limbs separately to a lesser degree. [22]

A number of studies have looked at effects of anaerobic exercise over months to years, showing it to be constant or slightly increased. A small case-control of anaerobic training in young untrained males over six weeks found decline in free testosterone of 17 percent. [37] With men in their 60s, resistive training over 16 weeks did not affect baseline anabolic hormone levels, although GH increased acutely with exercise. [38] A study over 21 weeks in male strength athletes showed basal hormone levels to be constant, despite strength increase. [39] A follow up study looked at a larger group of weight trainers over 24 weeks, with 12-week decompensation. Training caused no change in total testosterone, but there were decreases in free testosterone, progesterone, androstendione, DHEA, cortisol, transcortin, and in the cortisol:CBG ratio, suggesting androgen turnover increased with training intensity, without change in total testosterone. [20] A study looking at young men and resistance training over 48 weeks found increases in baseline serum testosterone from 20 ± 5 to 25 ± 5 nmol/L, and an increase in testosterone:SHBG ratio, LH and FSH. [5]

Combined training

One study showed GH increase with anaerobic effort to be blunted in those who performed aerobic training for 60 minutes prior to strength training. Testosterone levels remained high only at the end of the training session with aerobic training followed by strength training, a phenomenon not seen with weight training done before aerobics. [40] In an 11-week soccer training program focusing on combined vertical jumps, short sprints, and submaximal endurance running, total testosterone increased, but SHBG rose in parallel, maintaining a constant free androgen index. [41]

Related Research Articles

<span class="mw-page-title-main">Dehydroepiandrosterone</span> Chemical compound

Dehydroepiandrosterone (DHEA), also known as androstenolone, is an endogenous steroid hormone precursor. It is one of the most abundant circulating steroids in humans. DHEA is produced in the adrenal glands, the gonads, and the brain. It functions as a metabolic intermediate in the biosynthesis of the androgen and estrogen sex steroids both in the gonads and in various other tissues. However, DHEA also has a variety of potential biological effects in its own right, binding to an array of nuclear and cell surface receptors, and acting as a neurosteroid and modulator of neurotrophic factor receptors.

<span class="mw-page-title-main">Testosterone</span> Primary male sex hormone

Testosterone is the primary male sex hormone and androgen in males. In humans, testosterone plays a key role in the development of male reproductive tissues such as testes and prostate, as well as promoting secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair. It is associated with increased aggression, sex drive, the inclination to impress partners and other courting behaviors. In addition, testosterone in both sexes is involved in health and well-being, where it has a significant effect on overall mood, cognition, social and sexual behavior, metabolism and energy output, the cardiovascular system, and in the prevention of osteoporosis. Insufficient levels of testosterone in men may lead to abnormalities including frailty, accumulation of adipose fat tissue within the body, anxiety and depression, sexual performance issues, and bone loss.

<span class="mw-page-title-main">Exercise</span> Bodily activity intended to improve health

Exercise is intentional physical activity to enhance or maintain fitness and overall health.

<span class="mw-page-title-main">Aerobic exercise</span> Low to high intensity physical exercise

Aerobic exercise is physical exercise of low to high intensity that depends primarily on the aerobic energy-generating process. "Aerobic" is defined as "relating to, involving, or requiring oxygen", and refers to the use of oxygen to meet energy demands during exercise via aerobic metabolism adequately. Aerobic exercise is performed by repeating sequences of light-to-moderate intensity activities for extended periods of time. Examples of cardiovascular or aerobic exercise are medium- to long-distance running or jogging, swimming, cycling, stair climbing and walking.

<span class="mw-page-title-main">Exercise physiology</span>

Exercise physiology is the physiology of physical exercise. It is one of the allied health professions, and involves the study of the acute responses and chronic adaptations to exercise. Exercise physiologists are the highest qualified exercise professionals and utilise education, lifestyle intervention and specific forms of exercise to rehabilitate and manage acute and chronic injuries and conditions.

<span class="mw-page-title-main">Physical fitness</span> State of health and well-being

Physical fitness is a state of health and well-being and, more specifically, the ability to perform aspects of sports, occupations and daily activities. Physical fitness is generally achieved through proper nutrition, moderate-vigorous physical exercise, and sufficient rest along with a formal recovery plan.

<span class="mw-page-title-main">Anaerobic exercise</span> Physical exercise intense enough to cause lactate formation

Anaerobic exercise is a type of exercise that breaks down glucose in the body without using oxygen; anaerobic means "without oxygen". In practical terms, this means that anaerobic exercise is more intense, but shorter in duration than aerobic exercise.

<span class="mw-page-title-main">ZMA (supplement)</span> Bodybuilding supplement

ZMA is a supplement marketed towards athletes, gymnasts, and bodybuilders. It was developed by Victor Conte. No high-quality scientific study has found it to have any beneficial effects on muscle building or strength, and the International Society of Sports Nutrition and the Australian Institute of Sport regard it as having no clear benefits.

<span class="mw-page-title-main">Strength training</span> Performance of physical exercises designed to improve strength

Strength training, also known as weight training or resistance training, involves the performance of physical exercises that are designed to improve strength and endurance. It is often associated with the lifting of weights. It can also incorporate a variety of training techniques such as bodyweight exercises, isometrics, and plyometrics.

<span class="mw-page-title-main">High-intensity interval training</span> Exercise strategy

High-intensity interval training (HIIT) is a training protocol alternating short periods of intense or explosive anaerobic exercise with brief recovery periods until the point of exhaustion. HIIT involves exercises performed in repeated quick bursts at maximum or near maximal effort with periods of rest or low activity between bouts. The very high level of intensity, the interval duration, and number of bouts distinguish it from aerobic (cardiovascular) activity, because the body significantly recruits anaerobic energy systems. The method thereby relies on "the anaerobic energy releasing system almost maximally".

<span class="mw-page-title-main">Excess post-exercise oxygen consumption</span> Increased rate of oxygen intake following strenuous activity

Excess post-exercise oxygen consumption is a measurably increased rate of oxygen intake following strenuous activity. In historical contexts the term "oxygen debt" was popularized to explain or perhaps attempt to quantify anaerobic energy expenditure, particularly as regards lactic acid/lactate metabolism; in fact, the term "oxygen debt" is still widely used to this day. However, direct and indirect calorimeter experiments have definitively disproven any association of lactate metabolism as causal to an elevated oxygen uptake.

<span class="mw-page-title-main">Sex hormone-binding globulin</span> Human glycoprotein that binds to androgens and estrogens

Sex hormone-binding globulin (SHBG) or sex steroid-binding globulin (SSBG) is a glycoprotein that binds to androgens and estrogens. When produced by the Sertoli cells in the seminiferous tubules of the testis, it is called androgen-binding protein (ABP).

<span class="mw-page-title-main">Danazol</span> Chemical compound

Danazol, sold as Danocrine and other brand names, is a medication used in the treatment of endometriosis, fibrocystic breast disease, hereditary angioedema and other conditions. It is taken by mouth.

<span class="mw-page-title-main">Pattern hair loss</span> Medical condition

Pattern hair loss (also known as androgenetic alopecia (AGA)) is a hair loss condition that primarily affects the top and front of the scalp. In male-pattern hair loss (MPHL), the hair loss typically presents itself as either a receding front hairline, loss of hair on the crown (vertex) of the scalp, or a combination of both. Female-pattern hair loss (FPHL) typically presents as a diffuse thinning of the hair across the entire scalp.

<span class="mw-page-title-main">Sports nutrition</span> Study and practice of nutrition to improve performance

Sports nutrition is the study and practice of nutrition and diet with regards to improving anyone's athletic performance. Nutrition is an important part of many sports training regimens, being popular in strength sports and endurance sports. Sports nutrition focuses its studies on the type, as well as the quantity of fluids and food taken by an athlete. In addition, it deals with the consumption of nutrients such as vitamins, minerals, supplements and organic substances that include carbohydrates, proteins and fats.

<span class="mw-page-title-main">Endurance training</span>

Endurance training is the act of exercising to increase endurance. The term endurance training generally refers to training the aerobic system as opposed to the anaerobic system. The need for endurance in sports is often predicated as the need of cardiovascular and simple muscular endurance, but the issue of endurance is far more complex. Endurance can be divided into two categories including: general endurance and specific endurance. It can be shown that endurance in sport is closely tied to the execution of skill and technique. A well conditioned athlete can be defined as, the athlete who executes his or her technique consistently and effectively with the least effort. Key for measuring endurance are heart rate, power in cycling and pace in running.

<span class="mw-page-title-main">Muscle hypertrophy</span> Enlargement or overgrowth of a muscle organ

Muscle hypertrophy or muscle building involves a hypertrophy or increase in size of skeletal muscle through a growth in size of its component cells. Two factors contribute to hypertrophy: sarcoplasmic hypertrophy, which focuses more on increased muscle glycogen storage; and myofibrillar hypertrophy, which focuses more on increased myofibril size. It is the primary focus of bodybuilding-related activities.

A myokine is one of several hundred cytokines or other small proteins and proteoglycan peptides that are produced and released by skeletal muscle cells in response to muscular contractions. They have autocrine, paracrine and/or endocrine effects; their systemic effects occur at picomolar concentrations.

<span class="mw-page-title-main">Gynecomastia</span> Endocrine system disorder of human male breast

Gynecomastia is the abnormal non-cancerous enlargement of one or both breasts in males due to the growth of breast tissue as a result of a hormone imbalance between estrogens and androgens. Gynecomastia can cause significant psychological distress or unease.

In human biology, the testosterone–cortisol ratio describes the ratio between testosterone, the primary male sex hormone and an anabolic steroid, and cortisol, another steroid hormone, in the human body.

References

  1. 1 2 Arce JC, De Souza MJ, Pescatello LS, Luciano AA (1993). "Subclinical alterations in hormone and semen profile in athletes". Fertility and Sterility. 59 (2): 398–404. doi:10.1016/S0015-0282(16)55684-2. PMID   8425638.
  2. ↑ Hackney AC, Sinning WE, Bruot BC (1988). "Reproductive hormonal profiles of endurance-trained and untrained males". Medicine & Science in Sports & Exercise. 20 (1): 60–65. doi: 10.1249/00005768-198802000-00009 . PMID   3343919.
  3. ↑ Wheeler GD, Wall SR, Belcastro AN, Cumming DC (1984). "Reduced serum testosterone and prolactin levels in male distance runners". JAMA: The Journal of the American Medical Association. 252 (4): 514–516. doi:10.1001/jama.252.4.514. PMID   6429357.
  4. ↑ Cooper CS, Taaffe DR, Guido D, Packer E, Holloway L, Marcus R (1998). "Relationship of chronic endurance exercise to the somatotropic and sex hormone status of older men". European Journal of Endocrinology. 138 (5): 517–523. CiteSeerX   10.1.1.522.1665 . doi:10.1530/eje.0.1380517. PMID   9625362. S2CID   39766021.
  5. 1 2 Häkkinen K, Pakarinen A, Alen M, Kauhanen H, Komi PV (1988). "Neuromuscular and hormonal adaptations in athletes to strength training in two years". Journal of Applied Physiology. 65 (6): 2406–2412. doi:10.1152/jappl.1988.65.6.2406. PMID   3215840. S2CID   31491321.
  6. ↑ Muller M, den Tonkelaar I, Thijssen JH, Grobbee DE, van der Schouw YT (2003). "Endogenous sex hormones in men aged 40-80 years". European Journal of Endocrinology. 149 (6): 583–589. doi: 10.1530/eje.0.1490583 . PMID   14641001.
  7. ↑ Kraemer WJ, Häkkinen K, Newton RU, McCormick M, Nindl BC, Volek JS, Gotshalk LA, Fleck SJ, Campbell WW, Gordon SE, Farrell PA, Evans WJ (1998). "Acute hormonal responses to heavy resistance exercise in younger and older men". European Journal of Applied Physiology and Occupational Physiology. 77 (3): 206–211. doi:10.1007/s004210050323. PMID   9535580. S2CID   2888661.
  8. ↑ Tremblay MS, Copeland JL, Van Helder W (2004). "Effect of training status and exercise mode on endogenous steroid hormones in men". Journal of Applied Physiology. 96 (2): 531–539. doi:10.1152/japplphysiol.00656.2003. PMID   14514704. S2CID   12617397.
  9. 1 2 Hackney AC, Premo MC, McMurray RG (1995). "Influence of aerobic versus anaerobic exercise on the relationship between reproductive hormones in men". Journal of Sports Sciences. 13 (4): 305–311. doi:10.1080/02640419508732244. PMID   7474044.
  10. ↑ Fellmann N, Coudert J, Jarrige JF, Bedu M, Denis C, Boucher D, Lacour JR (2008). "Effects of Endurance Training on the Androgenic Response to Exercise in Man". International Journal of Sports Medicine. 6 (4): 215–219. doi:10.1055/s-2008-1025843. PMID   4044106.
  11. ↑ Hackney AC, Fahrner CL, Gulledge TP (1998). "Basal reproductive hormonal profiles are altered in endurance trained men". The Journal of Sports Medicine and Physical Fitness. 38 (2): 138–141. PMID   9763799.
  12. ↑ Jensen J, Oftebro H, Breigan B, Johnsson A, Ohlin K, Meen HD, Strømme SB, Dahl HA (1991). "Comparison of changes in testosterone concentrations after strength and endurance exercise in well trained men". European Journal of Applied Physiology and Occupational Physiology. 63 (6): 467–471. doi:10.1007/bf00868080. PMID   1765061. S2CID   2902279.
  13. ↑ Hawkins VN, Foster-Schubert K, Chubak J, Sorensen B, Ulrich CM, Stancyzk FZ, Plymate S, Stanford J, White E, Potter JD, McTiernan A (2008). "Effect of Exercise on Serum Sex Hormones in Men". Medicine & Science in Sports & Exercise. 40 (2): 223–233. doi:10.1249/mss.0b013e31815bbba9. PMC   3040039 . PMID   18202581.
  14. ↑ Lupo C, Baldi L, Bonifazi M, Lodi L, Martelli G, Viti A, Carli G (1985). "Androgen levels following a football match". European Journal of Applied Physiology and Occupational Physiology. 54 (5): 494–496. doi:10.1007/bf00422958. PMID   4085477. S2CID   34586537.
  15. ↑ Sato K, Iemitsu M, Aizawa K, Mesaki N, Ajisaka R, Fujita S (2012). "DHEA administration and exercise training improves insulin resistance in obese rats". Nutrition & Metabolism. 9: 47. doi: 10.1186/1743-7075-9-47 . PMC   3433349 . PMID   22647230.
  16. ↑ Daly W, Seegers CA, Rubin DA, Dobridge JD, Hackney AC (2004). "Relationship between stress hormones and testosterone with prolonged endurance exercise". European Journal of Applied Physiology. 93 (4): 375–380. doi:10.1007/s00421-004-1223-1. PMID   15618989. S2CID   26040852.
  17. ↑ Dressendorfer RH, Wade CE (1991). "Effects of a 15-d race on plasma steroid levels and leg muscle fitness in runners". Medicine & Science in Sports & Exercise. 23 (8): 954–958. doi:10.1249/00005768-199108000-00012. PMID   1956271.
  18. ↑ Morville R, Pesquies PC, Guezennec CY, Serrurier BD, Guignard M (1979). "Plasma variations in testicular and adrenal androgens during prolonged physical exercise in man". Annales d'Endocrinologie. 40 (5): 501–510. PMID   518032.
  19. ↑ Bunt JC (1986). "Hormonal alterations due to exercise". Sports Medicine. 3 (5): 331–345. doi:10.2165/00007256-198603050-00003. PMID   3529282. S2CID   25142021.
  20. 1 2 Alén M, Pakarinen A, Häkkinen K, Komi PV (1988). "Responses of serum androgenic-anabolic and catabolic hormones to prolonged strength training". International Journal of Sports Medicine. 9 (3): 229–233. doi:10.1055/s-2007-1025011. PMID   3410630.
  21. 1 2 Häkkinen K, Pakarinen A, Alén M, Kauhanen H, Komi PV (1987). "Relationships between training volume, physical performance capacity, and serum hormone concentrations during prolonged training in elite weight lifters". International Journal of Sports Medicine. 8 (Suppl 1): 61–65. doi:10.1055/s-2008-1025705. PMID   3108174.
  22. 1 2 Häkkinen K, Pakarinen A, Newton RU, Kraemer WJ (1998). "Acute hormone responses to heavy resistance lower and upper extremity exercise in young versus old men". European Journal of Applied Physiology and Occupational Physiology. 77 (4): 312–319. doi:10.1007/s004210050339. PMID   9562359. S2CID   24953856.
  23. ↑ McMurray RG, Eubank TK, Hackney AC (1995). "Nocturnal hormonal responses to resistance exercise". European Journal of Applied Physiology and Occupational Physiology. 72 (1–2): 121–126. doi:10.1007/bf00964126. PMID   8789582. S2CID   33470353.
  24. ↑ Willoughby DS, Taylor L (2004). "Effects of sequential bouts of resistance exercise on androgen receptor expression". Medicine & Science in Sports & Exercise. 36 (9): 1499–1506. doi: 10.1249/01.mss.0000139795.83030.d1 . PMID   15354030.
  25. ↑ Häkkinen K, Pakarinen A (2007). "Acute Hormonal Responses to Heavy Resistance Exercise in Men and Women at Different Ages". International Journal of Sports Medicine. 16 (8): 507–513. doi:10.1055/s-2007-973045. PMID   8776203.
  26. ↑ Baker JR, Bemben MG, Anderson MA, Bemben DA (2006). "Effects of Age on Testosterone Responses to Resistance Exercise and Musculoskeletal Variables in Men". The Journal of Strength and Conditioning Research. 20 (4): 874–881. doi:10.1519/R-18885.1. PMID   17194250. S2CID   45364148.
  27. 1 2 Smilios I, Pilianidis T, Karamouzis M, Parlavantzas A, Tokmakidis SP (2007). "Hormonal Responses after a Strength Endurance Resistance Exercise Protocol in Young and Elderly Males". International Journal of Sports Medicine. 28 (5): 401–406. doi:10.1055/s-2006-924366. PMID   17024619.
  28. 1 2 Smilios I, Pilianidis T, Karamouzis M, Tokmakidis SP (2003). "Hormonal Responses after Various Resistance Exercise Protocols". Medicine & Science in Sports & Exercise. 35 (4): 644–654. doi: 10.1249/01.MSS.0000058366.04460.5F . PMID   12673149. S2CID   24677567.
  29. ↑ Pullinen T, Mero A, Huttunen P, Pakarinen A, Komi PV (2002). "Resistance exercise-induced hormonal responses in men, women, and pubescent boys". Medicine & Science in Sports & Exercise. 34 (5): 806–813. doi: 10.1097/00005768-200205000-00013 . PMID   11984299.
  30. ↑ Kraemer RR, Kilgore JL, Kraemer GR, Castracane VD (1992). "Growth hormone, IGF-I, and testosterone responses to resistive exercise". Medicine & Science in Sports & Exercise. 24 (12): 1346–1352. doi:10.1249/00005768-199212000-00007. PMID   1470017.
  31. ↑ Raastad T, Glomsheller T, Bjøro T, Hallén J (2001). "Changes in human skeletal muscle contractility and hormone status during 2 weeks of heavy strength training". European Journal of Applied Physiology. 84 (1–2): 54–63. doi:10.1007/s004210000328. PMID   11394254. S2CID   23082825.
  32. ↑ Bergendahl M, Aloi JA, Iranmanesh A, Mulligan TM, Veldhuis JD (1998). "Fasting suppresses pulsatile luteinizing hormone (LH) secretion and enhances orderliness of LH release in young but not older men". The Journal of Clinical Endocrinology and Metabolism. 83 (6): 1967–1975. doi: 10.1210/jcem.83.6.4856 . PMID   9626127. S2CID   41824323.
  33. ↑ Kraemer WJ, Marchitelli L, Gordon SE, Harman E, Dziados JE, Mello R, Frykman P, McCurry D, Fleck SJ (1990). "Hormonal and growth factor responses to heavy resistance exercise protocols". Journal of Applied Physiology. 69 (4): 1442–1450. doi:10.1152/jappl.1990.69.4.1442. PMID   2262468. S2CID   9118093.
  34. ↑ Busso T, Häkkinen K, Pakarinen A, Kauhanen H, Komi PV, Lacour JR (1992). "Hormonal adaptations and modelled responses in elite weightlifters during 6 weeks of training". European Journal of Applied Physiology and Occupational Physiology. 64 (4): 381–386. doi:10.1007/bf00636228. PMID   1592066. S2CID   11187482.
  35. ↑ Ahtiainen JP, Pakarinen A, Alen M, Kraemer WJ, Häkkinen K (2005). "Short vs. Long Rest Period Between the Sets in Hypertrophic Resistance Training: Influence on Muscle Strength, Size, and Hormonal Adaptations in Trained Men". The Journal of Strength and Conditioning Research. 19 (3): 572–582. doi:10.1519/15604.1. PMID   16095405. S2CID   5804031.
  36. ↑ McCaulley GO, McBride JM, Cormie P, Hudson MB, Nuzzo JL, Quindry JC, Travis Triplett N (2008). "Acute hormonal and neuromuscular responses to hypertrophy, strength and power type resistance exercise". European Journal of Applied Physiology. 105 (5): 695–704. doi:10.1007/s00421-008-0951-z. PMID   19066934. S2CID   20770624.
  37. ↑ Ara I, Perez-Gomez J, Vicente-Rodriguez G, Chavarren J, Dorado C, Calbet JA (2006). "Serum free testosterone, leptin and soluble leptin receptor changes in a 6-week strength-training programme". The British Journal of Nutrition. 96 (6): 1053–1059. doi: 10.1017/bjn20061956 . PMID   17181880.
  38. ↑ Nicklas BJ, Ryan AJ, Treuth MM, Harman SM, Blackman MR, Hurley BF, Rogers MA (2007). "Testosterone, Growth Hormone and IGF-I Responses to Acute and Chronic Resistive Exercise in Men Aged 55-70 Years". International Journal of Sports Medicine. 16 (7): 445–450. doi:10.1055/s-2007-973035. PMID   8550252.
  39. ↑ Ahtiainen JP, Pakarinen A, Alen M, Kraemer WJ, Häkkinen K (2003). "Muscle hypertrophy, hormonal adaptations and strength development during strength training in strength-trained and untrained men". European Journal of Applied Physiology. 89 (6): 555–563. doi:10.1007/s00421-003-0833-3. PMID   12734759. S2CID   21764100.
  40. ↑ Goto K, Higashiyama M, Ishii N, Takamatsu K (2005). "Prior endurance exercise attenuates growth hormone response to subsequent resistance exercise". European Journal of Applied Physiology. 94 (3): 333–338. doi:10.1007/s00421-004-1296-x. PMID   15714290. S2CID   26717547.
  41. ↑ Gorostiaga EM, Izquierdo M, Ruesta M, Iribarren J, González-Badillo JJ, Ibáñez J (2003). "Strength training effects on physical performance and serum hormones in young soccer players". European Journal of Applied Physiology. 91 (5–6): 698–707. doi:10.1007/s00421-003-1032-y. PMID   14704801. S2CID   4334962.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.