Endocrine responses to acute and chronic high-altitude exposure (4,300 meters): Modulating effects of caloric restriction

Kimberly E. Barnholt, Andrew R. Hoffman, Paul B. Rock, Stephen R. Muza, Charles S. Fulco, Barry Braun, Leah Holloway, Robert S. Mazzeo, Allen Cymerman, Anne L. Friedlander

Research output: Contribution to journalArticle

83 Citations (Scopus)

Abstract

High-altitude anorexia leads to a hormonal response pattern modulated by both hypoxia and caloric restriction (CR). The purpose of this study was to compare altitude-induced neuroendocrine changes with or without energy imbalance and to explore how energy sufficiency alters the endocrine acclimatization process. Twenty-six normal-weight, young men were studied for 3 wk. One group [hypocaloric group (HYPO), n = 9] stayed at sea level and consumed 40% fewer calories than required to maintain body weight. Two other groups were deployed to 4,300 meters (Pikes Peak, CO), where one group (ADQ, n = 7) was adequately fed to maintain body weight and the other [deficient group (DEF), n = 10] had calories restricted as above. HYPO experienced a typical CR-induced reduction in many hormones such as insulin, testosterone, and leptin. At altitude, fasting glucose, insulin, and epinephrine exhibited a muted rise in DEF compared with ADQ. Free thyroxine, thyroid-stimulating hormone, and norepinephrine showed similar patterns between the two altitude groups. Morning cortisol initially rose higher in DEF than ADQ at 4,300 meters, but the difference disappeared by day 5. Testosterone increased in both altitude groups acutely but declined over time in DEF only. Adiponectin and leptin did not change significantly from sea level baseline values in either altitude group regardless of energy intake. These data suggest that hypoxia tends to increase blood hormone concentrations, but anorexia suppresses elements of the endocrine response. Such suppression results in the preservation of energy stores but may sacrifice the facilitation of oxygen delivery and the use of oxygen-efficient fuels.

Original languageEnglish
Pages (from-to)E1078-E1088
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume290
Issue number6
DOIs
StatePublished - 14 Jun 2006

Fingerprint

Caloric Restriction
Anorexia
Leptin
Oceans and Seas
Testosterone
Body Weight
Esocidae
Hormones
Insulin
Oxygen
Acclimatization
Adiponectin
Response Elements
Thyrotropin
Carbon Monoxide
Energy Intake
Thyroxine
Epinephrine
Hydrocortisone
Fasting

Keywords

  • Acclimatization
  • Altitude
  • Caloric restriction
  • Energy balance
  • Hormones
  • Hypoxia

Cite this

Barnholt, Kimberly E. ; Hoffman, Andrew R. ; Rock, Paul B. ; Muza, Stephen R. ; Fulco, Charles S. ; Braun, Barry ; Holloway, Leah ; Mazzeo, Robert S. ; Cymerman, Allen ; Friedlander, Anne L. / Endocrine responses to acute and chronic high-altitude exposure (4,300 meters) : Modulating effects of caloric restriction. In: American Journal of Physiology - Endocrinology and Metabolism. 2006 ; Vol. 290, No. 6. pp. E1078-E1088.
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Barnholt, KE, Hoffman, AR, Rock, PB, Muza, SR, Fulco, CS, Braun, B, Holloway, L, Mazzeo, RS, Cymerman, A & Friedlander, AL 2006, 'Endocrine responses to acute and chronic high-altitude exposure (4,300 meters): Modulating effects of caloric restriction', American Journal of Physiology - Endocrinology and Metabolism, vol. 290, no. 6, pp. E1078-E1088. https://doi.org/10.1152/ajpendo.00449.2005

Endocrine responses to acute and chronic high-altitude exposure (4,300 meters) : Modulating effects of caloric restriction. / Barnholt, Kimberly E.; Hoffman, Andrew R.; Rock, Paul B.; Muza, Stephen R.; Fulco, Charles S.; Braun, Barry; Holloway, Leah; Mazzeo, Robert S.; Cymerman, Allen; Friedlander, Anne L.

In: American Journal of Physiology - Endocrinology and Metabolism, Vol. 290, No. 6, 14.06.2006, p. E1078-E1088.

Research output: Contribution to journalArticle

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T1 - Endocrine responses to acute and chronic high-altitude exposure (4,300 meters)

T2 - Modulating effects of caloric restriction

AU - Barnholt, Kimberly E.

AU - Hoffman, Andrew R.

AU - Rock, Paul B.

AU - Muza, Stephen R.

AU - Fulco, Charles S.

AU - Braun, Barry

AU - Holloway, Leah

AU - Mazzeo, Robert S.

AU - Cymerman, Allen

AU - Friedlander, Anne L.

PY - 2006/6/14

Y1 - 2006/6/14

N2 - High-altitude anorexia leads to a hormonal response pattern modulated by both hypoxia and caloric restriction (CR). The purpose of this study was to compare altitude-induced neuroendocrine changes with or without energy imbalance and to explore how energy sufficiency alters the endocrine acclimatization process. Twenty-six normal-weight, young men were studied for 3 wk. One group [hypocaloric group (HYPO), n = 9] stayed at sea level and consumed 40% fewer calories than required to maintain body weight. Two other groups were deployed to 4,300 meters (Pikes Peak, CO), where one group (ADQ, n = 7) was adequately fed to maintain body weight and the other [deficient group (DEF), n = 10] had calories restricted as above. HYPO experienced a typical CR-induced reduction in many hormones such as insulin, testosterone, and leptin. At altitude, fasting glucose, insulin, and epinephrine exhibited a muted rise in DEF compared with ADQ. Free thyroxine, thyroid-stimulating hormone, and norepinephrine showed similar patterns between the two altitude groups. Morning cortisol initially rose higher in DEF than ADQ at 4,300 meters, but the difference disappeared by day 5. Testosterone increased in both altitude groups acutely but declined over time in DEF only. Adiponectin and leptin did not change significantly from sea level baseline values in either altitude group regardless of energy intake. These data suggest that hypoxia tends to increase blood hormone concentrations, but anorexia suppresses elements of the endocrine response. Such suppression results in the preservation of energy stores but may sacrifice the facilitation of oxygen delivery and the use of oxygen-efficient fuels.

AB - High-altitude anorexia leads to a hormonal response pattern modulated by both hypoxia and caloric restriction (CR). The purpose of this study was to compare altitude-induced neuroendocrine changes with or without energy imbalance and to explore how energy sufficiency alters the endocrine acclimatization process. Twenty-six normal-weight, young men were studied for 3 wk. One group [hypocaloric group (HYPO), n = 9] stayed at sea level and consumed 40% fewer calories than required to maintain body weight. Two other groups were deployed to 4,300 meters (Pikes Peak, CO), where one group (ADQ, n = 7) was adequately fed to maintain body weight and the other [deficient group (DEF), n = 10] had calories restricted as above. HYPO experienced a typical CR-induced reduction in many hormones such as insulin, testosterone, and leptin. At altitude, fasting glucose, insulin, and epinephrine exhibited a muted rise in DEF compared with ADQ. Free thyroxine, thyroid-stimulating hormone, and norepinephrine showed similar patterns between the two altitude groups. Morning cortisol initially rose higher in DEF than ADQ at 4,300 meters, but the difference disappeared by day 5. Testosterone increased in both altitude groups acutely but declined over time in DEF only. Adiponectin and leptin did not change significantly from sea level baseline values in either altitude group regardless of energy intake. These data suggest that hypoxia tends to increase blood hormone concentrations, but anorexia suppresses elements of the endocrine response. Such suppression results in the preservation of energy stores but may sacrifice the facilitation of oxygen delivery and the use of oxygen-efficient fuels.

KW - Acclimatization

KW - Altitude

KW - Caloric restriction

KW - Energy balance

KW - Hormones

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