Effects of continuous versus intermittent exercise, obesity, and gender on growth hormone secretion.
BACKGROUND
Obesity attenuates spontaneous GH secretion and the GH response to exercise. Obese individuals often have low fitness levels, limiting their ability to complete a typical 30-min bout of continuous exercise. An alternative regimen in obese subjects may be shorter bouts of exercise interspersed throughout the day.


OBJECTIVE
The objective of the study was to examine whether intermittent and continuous exercise interventions evoke similar patterns of 24-h GH secretion and whether responses are attenuated in obese subjects or affected by gender.


METHODS
This was a repeated-measures design in which each subject served as their own control.


METHODS
This study was conducted at the University of Virginia General Clinical Research Center.


METHODS
Subjects were healthy nonobese (n = 15) and obese (n = 14) young adults.


METHODS
Subjects were studied over 24 h at the General Clinical Research Center on three occasions: control, one 30-min bout of exercise, and three 10-min bouts of exercise.


METHODS
Twenty-four hour GH secretion was measured.


RESULTS
Compared with unstimulated 24-h GH secretion, both intermittent and continuous exercise, at constant exercise intensity, resulted in severalfold elevation of 24-h integrated serum GH concentrations in young adults. Basal and pulsatile modes of GH secretion were attenuated both at rest and during exercise in obese subjects.


CONCLUSIONS
The present data suggest that continuous and intermittent exercise training should be comparably effective in increasing 24-h GH secretion.
Weltman
Arthur
A
Department of Human Services, University of Virginia, Charlottesville, Virginia 22904, USA. alw2v@virginia.edu
Weltman
Judy Y
JY
Watson Winfield
Dee Dee
DD
Frick
Kirsten
K
Patrie
James
J
Kok
Petra
P
Keenan
Daniel M
DM
Gaesser
Glenn A
GA
Veldhuis
Johannes D
JD
D000328:Adult; D015308:Anaerobic Threshold / Q000502:physiology; D001823:Body Composition / Q000502:physiology; D015992:Body Mass Index; D003627:Data Interpretation, Statistical; D015444:Exercise / Q000502:physiology*; D005260:Female; D006207:Half-Life; D019382:Human Growth Hormone / Q000097:blood*; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D009765:Obesity / Q000097:blood / Q000378:metabolism*; D010809:Physical Fitness / Q000502:physiology*; D012146:Rest / Q000502:physiology; D012727:Sex Characteristics; D055815:Young Adult
D019382:Human Growth Hormone; D019344:Lactic Acid
J Clin Endocrinol Metab. 2001 Aug;86(8):3845-52
11502822
J Appl Physiol. 1974 Dec;37(6):826-30
4474159
Can J Cardiol. 2007 Oct;23 Suppl B:23B-31B
17932584
Ann N Y Acad Sci. 1963 Sep 26;110:113-40
14062375
J Appl Physiol (1985). 2000 Sep;89(3):937-46
10956336
J Appl Physiol (1985). 2006 May;100(5):1623-9
16384836
Int J Sports Med. 1990 Feb;11(1):26-32
2318561
J Appl Physiol (1985). 1999 Aug;87(2):498-504
10444604
J Appl Physiol. 1976 Oct;41(4):523-7
985395
J Clin Endocrinol Metab. 1991 Jan;72(1):51-9
1986027
Med Sci Sports Exerc. 1998 Jan;30(1):152-7
9475657
J Clin Endocrinol Metab. 1994 Mar;78(3):543-8
8126124
Neuroendocrinology. 1992 Jul;56(1):112-7
1641069
Am J Physiol Regul Integr Comp Physiol. 2000 Oct;279(4):R1467-77
11004017
Endocr Rev. 2006 Apr;27(2):101-40
16434512
J Appl Physiol (1985). 2006 Dec;101(6):1641-7
16946030
J Clin Endocrinol Metab. 1999 Sep;84(9):3156-61
10487680
JAMA. 1999 Oct 27;282(16):1554-60
10546695
J Appl Physiol (1985). 1992 Jun;72(6):2188-96
1629072
J Appl Physiol (1985). 1997 Nov;83(5):1756-61
9375348
Scand J Clin Lab Invest. 1973 Mar;31(2):175-8
4733195
J Appl Physiol (1985). 1994 Jun;76(6):2490-6
7928875
J Appl Physiol. 1967 Nov;23(5):811-3
6061401
Am J Physiol. 1999 Nov;277(5):E848-54
10567011
Am J Physiol. 1997 Jun;272(6 Pt 1):E1108-16
9227458
J Appl Physiol (1985). 2002 May;92(5):2053-60
11960957
J Appl Physiol. 1969 Jul;27(1):96-100
5786976
J Clin Endocrinol Metab. 1997 Mar;82(3):727-34
9062473
Am J Physiol Regul Integr Comp Physiol. 2003 Sep;285(3):R664-73
12738612
J Appl Physiol Respir Environ Exerc Physiol. 1983 Dec;55(6):1682-7
6662758
J Theor Biol. 2005 Oct 7;236(3):242-55
15916772
J Clin Endocrinol Metab. 1995 Nov;80(11):3209-22
7593428
Int J Obes Relat Metab Disord. 1995 Dec;19(12):893-901
8963358
Int J Obes Relat Metab Disord. 2000 May;24(5):566-72
10849577
Eur J Appl Physiol Occup Physiol. 1983;52(1):131-5
6360680
Am J Physiol. 1986 Apr;250(4 Pt 1):E486-93
3008572
Metabolism. 1996 Mar;45(3):362-9
8606645
J Clin Endocrinol Metab. 1986 Mar;62(3):551-6
3080465
J Clin Endocrinol Metab. 1992 Jul;75(1):157-62
1619005
Metabolism. 2003 Jan;52(1):73-80
12524665
J Clin Endocrinol Metab. 2005 Mar;90(3):1466-74
15598680
J Clin Endocrinol Metab. 1989 Mar;68(3):535-41
2563734
Diabet Med. 2006 May;23(5):469-80
16681555
J Appl Physiol (1985). 1999 Sep;87(3):1154-62
10484590
Eur J Appl Physiol Occup Physiol. 1996;73(1-2):117-20
8861679
Endocr Rev. 1998 Dec;19(6):717-97
9861545
Diabetes. 2004 Aug;53(8):2087-94
15277390
J Appl Physiol (1985). 1986 Nov;61(5):1796-801
3781988
J Clin Endocrinol Metab. 2004 Nov;89(11):5542-8
15531509
Clin Chem. 1998 Jan;44(1):116-23
9550568