The effect of exercise duration and mode on the growth hormone responses in young women on oral contraceptives

Sauro, Lynn M.; Kanaley, Jill A.

doi:10.1007/s00421-003-0863-x

Cited by 12 publications

(7 citation statements)

References 41 publications

(84 reference statements)

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“…Earlier work (23,24) has demonstrated that GH secretion increased during either short-duration maximal or prolonged submaximal exercise, but was significantly blunted in older men in comparison with their younger counterparts. Likewise we revealed that 30 min of exercise results in a significant increase in GH levels in postmenopausal black and white women, but compared with 20 min of submaximal exercise in younger premenopausal women this response is substantially lower than what we have reported previously (25). Although exercise appears to result in a significant increase in GH levels, it should be noted that 25% of the women had less than a 25% increase in the integrated GH concentrations over the resting day regardless of race or HRT use.…”

Section: Effects Of Race On Gh Concentrationscontrasting

confidence: 76%

Hormone-replacement therapy use, but not race, impacts the resting and exercise-induced GH response in postmenopausal women

et al. 2005

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Objective: This study examined the effect of hormone-replacement therapy (HRT) use on the incremental GH response to aerobic exercise in postmenopausal women and established whether racial differences in the GH response were seen at rest and in response to exercise. Methods: 13 white (n ¼ 6, HRT; n ¼ 7, no HRT) and seven black women (no HRT) were studied on two occasions, a control day and an exercise day (30 min at 70% VO 2 max on a cycle ergometer). Blood was sampled every 10 min for a 4-h period and analyzed for GH using an ultrasensitive chemiluminescent assay. Results: The mean 4-h GH concentration was higher on both study days in the HRT women than the non-HRT users. The integrated GH concentrations were greater in the HRT women both at rest and in response to exercise (rest, 352^53 min mg l 21; exercise, 711^57 min mg l 21; P , 0.01) than in the non-HRT women (rest, 157^87 min mg l 21; exercise, 248^94 min mg l 21 ). The incremental GH response was greater in the HRT users than in the non-HRT women (358^130 versus 90.8^94 min mg l 21 , respectively; P , 0.05). GH-production rate during the 4-h period was greater in the HRT women than in the non-HRT women (P , 0.01), due to an increase in the GH mass secreted/pulse (P , 0.05), with no change in GH pulse number or GH half-life. No racial differences in the mean 4-h GH concentrations or integrated GH concentrations were found at rest or in response to exercise. Conclusion: HRT use resulted in a greater incremental exercise response compared with non-HRT users, due to changes in the secretory pulse characteristics in the HRT users. This study also demonstrated that no racial differences exist at rest and in response to exercise in the morning hours.

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Section: Effects Of Race On Gh Concentrationscontrasting

confidence: 76%

Hormone-replacement therapy use, but not race, impacts the resting and exercise-induced GH response in postmenopausal women

et al. 2005

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“…Most studies investigating the influence of exercise duration have focused on the minimal exercise duration required to stimulate GH release. Results suggest a range of values, from <10 min to >15 min of exercise being required to elicit an initial rise in GH release (8,11,21,22,24,29,30,32). The inconsistencies in the findings are probably due to differences in the exercise intensity employed in different studies.…”

mentioning

confidence: 93%

The impact of sex and exercise duration on growth hormone secretion

Wideman

Consitt²,

Patrie³

et al. 2006

Journal of Applied Physiology

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Previous research clearly indicates a linear relationship between exercise intensity and growth hormone (GH) release and that this relationship is influenced by sex. The present study examined the GH response to increasing exercise duration in young men and women. Fifteen healthy subjects (8 men and 7 women) completed three randomly assigned exercise sessions (30, 60, and 120 min) at 70% of peak oxygen consumption. Blood samples were collected every 10 min beginning 30 min before exercise, for a total of 240 min. Total integrated GH concentration (IGHC) increased with increasing exercise duration for men and women (601, 1,394, and 2,360 microg/l.4 h; 659, 1,009 and 1,243 microg/l.4 h for 30, 60, and 120 min of exercise, respectively). Regression analysis revealed that IGHC (logarithmically transformed) was significantly influenced by exercise duration (logarithmically transformed) (120 min > 60 min > 30 min) and that a significant sex-dependent effect was present even after adjustments for fitness level and percent body fat (men > women). The slope of the regression line was greater for men than for women (1.003 vs. 0.612; P = 0.013), but the average height of the regression line was greater for women (7.287 vs. 6.595; P < 0.001). Although GH secretory pulse half-duration was greater in women (P = 0.001), and GH half-life was greater in men (P = 0.001), they were not affected by exercise duration. The total mass of GH secreted during exercise increased with exercise duration (P < 0.001) but was not affected by sex (P = 0.137). Results from the present investigation indicate that when exercise intensity is constant, exercise duration significantly increases IGHC and that this relationship is sex dependent.

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“…The early studies in this area demonstrated that both continuous and intermittent exercise results in increased GH concentrations, and a significant increase does not appear until approximately 15 min into exercise [10,11]. Considerable controversy has existed about the optimal exercise intensity for GH release.…”

Section: Exercise and Growth Hormone Responsesmentioning

confidence: 96%

Growth hormone, arginine and exercise

Kanaley

2008

Current Opinion in Clinical Nutrition and Metabolic Care

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Exercise is a very potent stimulator of growth hormone release and there is considerable research documenting the dramatic growth hormone rise. At rest oral L-arginine ingestion will enhance the growth hormone response and the combination of arginine plus exercise increases growth hormone, but this increase may be less than seen with exercise alone. This diminished response is seen in both in both younger and older individuals.

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The effect of exercise duration and mode on the growth hormone responses in young women on oral contraceptives

Cited by 12 publications

References 41 publications

Hormone-replacement therapy use, but not race, impacts the resting and exercise-induced GH response in postmenopausal women

Hormone-replacement therapy use, but not race, impacts the resting and exercise-induced GH response in postmenopausal women

The impact of sex and exercise duration on growth hormone secretion

Growth hormone, arginine and exercise

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