is observed in ~60% of the AM-PM pairs; ~30% have a positive diurnal change (D+), and ~10%
exhibit little difference (D0). Neither peak T (TP) nor minimum T (TM), regardless of time, differ
significantly between D- and D+. Mean TP and TM are comparable to similarly aged U.S. men.
A sample of U.S. college students (mean age = 20 years) comprises ~10% D+ and ~10% D0 (D.
Granger, personal communication). The relatively high proportion of D+ despite T levels
comparable to similiarly aged U.S. men suggests that the principal difference between HA and
LA men is in the rhythm of circadian change rather than the magitude of basal or maximum T.
However, it remains to be determined if, compared to these HA men, LA men having comparable
age, socioeconomic, dietary, and activity variables have lower frequencies of D+ and D0.
Likewise, it is unknown if similiarly aged HA men generally exhibit substantial proportions of
D+ and D0 regardless of socioeconomic variation. Supported by NSF (SBR 9506107), UC
Riverside, and SUNY Binghamton.
230.
THE ENERGY METABOLISM OF MUSCULAR ACTIVITY OF RUSSIAN OLYMPIC
TEAM WRESTLERS AT HIGH-ALTITUDES. Ilyin Vladimir
1
, Beloshitsky Pavel
1
, Potnichenko
Vladimir
2
, Evtushenko Alexey
1
, Kravchenko Yuriy
1
, Andiychuk Yuriy
1
. Elbrus Medical
Biological Station, NAS Ukraine
1
, Elbrus
2
.
The energy metabolism of muscular activity has been studied on Russian Olympic Team
Wrestlers at the end of their training cycle at the 2100 m altitude. Cyclergometric tests with step
power load have been used for evaluating physical performance according to metabolical and
functional parameters. The main parameter for such tests is the common value of aerobic and
anaerobic inputs for the whole training period. The coefficients of power, capacitance,
effectiveness, mobility and use of functional and energy systems were evaluated. It has been
shown that the endurance of wrestlers at the end of training cycle is high. Also, anaerobic type of
efficiency dominates against a background of more than average aerobic efficiency for majority
of them. The recovering after the load is aperiodical which is characteristic for high-class
sportsmen. The distinctive feature of energy metabolism for muscular activity for all wrestlers at
this altitude is that switching anaerobic (alactat and lactat) mechanisms of energy production
precedes reaching maximum oxygen consumption level. Also, it is shown, that at the end of the
training process the states of overstraining with non-satisfactory adaptation to training loads are
observed for 41% of wrestlers. The obtained results suggest the necessity of developing of special
training programs for high altitudes to eliminate the disregulating processes as they present the
main genesis factor for human organism dysfunctions connected with physical overstraining.
231.
EFFECT OF L-ARGININE SUPPLEMENTATION ON BREATH CONDENSATE VEGF,
EXHALED NO, PLASMA ERYTHROPOIETIN AND SUBJECTIVE SYMPTOMS AT 4383
M. William Walby
1
, Jim Mansoor
2
, Radhika Kajekar
1
, Brian Morrissey
1
, Ken Yoneda
1
, Maya
Juarez
1
, Marlowe Eldridge
3
, John Severinghaus
4
, Edward Schelegle
1
. University of California,
Davis, California
1
, University of the Pacific, Stockton, California
2
, University of Wisconsin,
Madison, Wisconsin
3
, University of California, San Francisco, California
4
.
Adaptation to the hypoxic stress of ascent to altitude increases the stabilization of the
hypoxia-inducible factor (HIF-1) that mediates the gene expression of erythropoietin (EPO) and
vascular endothelial growth factor (VEGF). Recent observations in renal tubular cells, in
normoxia, show that nitric oxide (NO) increases the stability of HIF-1. In the current study we
examined whether dietary supplementation with L-arginine (the substrate for NO synthesis) leads
to increased synthesis of VEGF and EPO. Seven healthy male adults consumed a liquid mixture
containing L-arginine (4 gms/200 ml, every 8 hours for 48 hours, beginning 24 hours prior to
ascent) or placebo. Subjects were transported from White Mountain Research Center (1235 m) to
White Mountain Summit Hut (4383 m) in sport utility vehicles over the course of 3-4 hours. We
measured exhaled breath condensates and exhaled NO, plasma concentration of EPO, O2
saturation, respiratory related sensations, and sensations of acute mountain sickness at rest and
during exercise through the course of 24 hours at altitude. Measurements were taken upon arrival
