Operation Everest II: Metabolic and hormonal responses to incremental exercise to exhaustion

P. M. Young, J. R. Sutton, H. J. Green, J. T. Reeves, Paul Rock, C. S. Houston, A. Cymerman

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

The reasons for the reduced exercise capacities observed at high altitudes are not completely known. Substrate availability or accumulations of lactate and ammonium could have significant roles. As part of Operation Everest II, peak oxygen uptakes were determined in five normal male volunteers with use of progressively increasing cycling work loads at ambient barometric pressures of 760, 380, and 282 Torr. Decrements from sea level (SL) to 380 and 282 Torr occurred in peak power output (19 and 47%), time to exhaustion (19 and 48%), and oxygen uptake (41 and 61%), respectively. Arterial saturations after exhaustive exercise were decreased to 63% at 380 Torr and 39% at 282 Torr. At 380 and 282 Torr, postexercise plasma concentrations of glucose and free fatty acids were not increased, whereas plasma glycerol concentrations were decreased relative to SL (145 ± 24 μM at 380 Torr and 77 ± 10 μM at 282 Torr vs. 213 ± 24 μM at SL). Preexercise plasma insulin concentrations were elevated at both 380 and 282 Torr (87 ± 16 pM at 380 Torr and 85 ± 18 pM at 282 Torr vs. 41 ± 30 pM at SL). In general, postexercise concentrations of plasma catecholamines were decreased at altitude compared with SL. Preexercise lactate and ammonium concentrations were not different at any simulated altitude. From these data neither substrate availability nor metabolic product accumulation limited exercise capacity at extreme simulated altitude.

Original languageEnglish
Pages (from-to)2574-2579
Number of pages6
JournalJournal of Applied Physiology
Volume73
Issue number6
StatePublished - 1 Dec 1992

Fingerprint

Oceans and Seas
Exercise
Lactic Acid
Oxygen
Workload
Nonesterified Fatty Acids
Glycerol
Catecholamines
Healthy Volunteers
Insulin
Pressure
Glucose

Keywords

  • altitude
  • blood lactate
  • epinephrine
  • exercise endurance
  • insulin
  • norepinephrine
  • plasma ammonium
  • plasma catecholamines

Cite this

Young, P. M., Sutton, J. R., Green, H. J., Reeves, J. T., Rock, P., Houston, C. S., & Cymerman, A. (1992). Operation Everest II: Metabolic and hormonal responses to incremental exercise to exhaustion. Journal of Applied Physiology, 73(6), 2574-2579.
Young, P. M. ; Sutton, J. R. ; Green, H. J. ; Reeves, J. T. ; Rock, Paul ; Houston, C. S. ; Cymerman, A. / Operation Everest II : Metabolic and hormonal responses to incremental exercise to exhaustion. In: Journal of Applied Physiology. 1992 ; Vol. 73, No. 6. pp. 2574-2579.
@article{566335a63f414d729dd949d690083aeb,
title = "Operation Everest II: Metabolic and hormonal responses to incremental exercise to exhaustion",
abstract = "The reasons for the reduced exercise capacities observed at high altitudes are not completely known. Substrate availability or accumulations of lactate and ammonium could have significant roles. As part of Operation Everest II, peak oxygen uptakes were determined in five normal male volunteers with use of progressively increasing cycling work loads at ambient barometric pressures of 760, 380, and 282 Torr. Decrements from sea level (SL) to 380 and 282 Torr occurred in peak power output (19 and 47{\%}), time to exhaustion (19 and 48{\%}), and oxygen uptake (41 and 61{\%}), respectively. Arterial saturations after exhaustive exercise were decreased to 63{\%} at 380 Torr and 39{\%} at 282 Torr. At 380 and 282 Torr, postexercise plasma concentrations of glucose and free fatty acids were not increased, whereas plasma glycerol concentrations were decreased relative to SL (145 ± 24 μM at 380 Torr and 77 ± 10 μM at 282 Torr vs. 213 ± 24 μM at SL). Preexercise plasma insulin concentrations were elevated at both 380 and 282 Torr (87 ± 16 pM at 380 Torr and 85 ± 18 pM at 282 Torr vs. 41 ± 30 pM at SL). In general, postexercise concentrations of plasma catecholamines were decreased at altitude compared with SL. Preexercise lactate and ammonium concentrations were not different at any simulated altitude. From these data neither substrate availability nor metabolic product accumulation limited exercise capacity at extreme simulated altitude.",
keywords = "altitude, blood lactate, epinephrine, exercise endurance, insulin, norepinephrine, plasma ammonium, plasma catecholamines",
author = "Young, {P. M.} and Sutton, {J. R.} and Green, {H. J.} and Reeves, {J. T.} and Paul Rock and Houston, {C. S.} and A. Cymerman",
year = "1992",
month = "12",
day = "1",
language = "English",
volume = "73",
pages = "2574--2579",
journal = "Journal of Applied Physiology",
issn = "8750-7587",
publisher = "American Physiological Society",
number = "6",

}

Young, PM, Sutton, JR, Green, HJ, Reeves, JT, Rock, P, Houston, CS & Cymerman, A 1992, 'Operation Everest II: Metabolic and hormonal responses to incremental exercise to exhaustion', Journal of Applied Physiology, vol. 73, no. 6, pp. 2574-2579.

Operation Everest II : Metabolic and hormonal responses to incremental exercise to exhaustion. / Young, P. M.; Sutton, J. R.; Green, H. J.; Reeves, J. T.; Rock, Paul; Houston, C. S.; Cymerman, A.

In: Journal of Applied Physiology, Vol. 73, No. 6, 01.12.1992, p. 2574-2579.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Operation Everest II

T2 - Metabolic and hormonal responses to incremental exercise to exhaustion

AU - Young, P. M.

AU - Sutton, J. R.

AU - Green, H. J.

AU - Reeves, J. T.

AU - Rock, Paul

AU - Houston, C. S.

AU - Cymerman, A.

PY - 1992/12/1

Y1 - 1992/12/1

N2 - The reasons for the reduced exercise capacities observed at high altitudes are not completely known. Substrate availability or accumulations of lactate and ammonium could have significant roles. As part of Operation Everest II, peak oxygen uptakes were determined in five normal male volunteers with use of progressively increasing cycling work loads at ambient barometric pressures of 760, 380, and 282 Torr. Decrements from sea level (SL) to 380 and 282 Torr occurred in peak power output (19 and 47%), time to exhaustion (19 and 48%), and oxygen uptake (41 and 61%), respectively. Arterial saturations after exhaustive exercise were decreased to 63% at 380 Torr and 39% at 282 Torr. At 380 and 282 Torr, postexercise plasma concentrations of glucose and free fatty acids were not increased, whereas plasma glycerol concentrations were decreased relative to SL (145 ± 24 μM at 380 Torr and 77 ± 10 μM at 282 Torr vs. 213 ± 24 μM at SL). Preexercise plasma insulin concentrations were elevated at both 380 and 282 Torr (87 ± 16 pM at 380 Torr and 85 ± 18 pM at 282 Torr vs. 41 ± 30 pM at SL). In general, postexercise concentrations of plasma catecholamines were decreased at altitude compared with SL. Preexercise lactate and ammonium concentrations were not different at any simulated altitude. From these data neither substrate availability nor metabolic product accumulation limited exercise capacity at extreme simulated altitude.

AB - The reasons for the reduced exercise capacities observed at high altitudes are not completely known. Substrate availability or accumulations of lactate and ammonium could have significant roles. As part of Operation Everest II, peak oxygen uptakes were determined in five normal male volunteers with use of progressively increasing cycling work loads at ambient barometric pressures of 760, 380, and 282 Torr. Decrements from sea level (SL) to 380 and 282 Torr occurred in peak power output (19 and 47%), time to exhaustion (19 and 48%), and oxygen uptake (41 and 61%), respectively. Arterial saturations after exhaustive exercise were decreased to 63% at 380 Torr and 39% at 282 Torr. At 380 and 282 Torr, postexercise plasma concentrations of glucose and free fatty acids were not increased, whereas plasma glycerol concentrations were decreased relative to SL (145 ± 24 μM at 380 Torr and 77 ± 10 μM at 282 Torr vs. 213 ± 24 μM at SL). Preexercise plasma insulin concentrations were elevated at both 380 and 282 Torr (87 ± 16 pM at 380 Torr and 85 ± 18 pM at 282 Torr vs. 41 ± 30 pM at SL). In general, postexercise concentrations of plasma catecholamines were decreased at altitude compared with SL. Preexercise lactate and ammonium concentrations were not different at any simulated altitude. From these data neither substrate availability nor metabolic product accumulation limited exercise capacity at extreme simulated altitude.

KW - altitude

KW - blood lactate

KW - epinephrine

KW - exercise endurance

KW - insulin

KW - norepinephrine

KW - plasma ammonium

KW - plasma catecholamines

UR - http://www.scopus.com/inward/record.url?scp=0027086858&partnerID=8YFLogxK

M3 - Article

C2 - 1490971

AN - SCOPUS:0027086858

VL - 73

SP - 2574

EP - 2579

JO - Journal of Applied Physiology

JF - Journal of Applied Physiology

SN - 8750-7587

IS - 6

ER -

Young PM, Sutton JR, Green HJ, Reeves JT, Rock P, Houston CS et al. Operation Everest II: Metabolic and hormonal responses to incremental exercise to exhaustion. Journal of Applied Physiology. 1992 Dec 1;73(6):2574-2579.