The Effect of Normobaric Normoxic and Hypoxic Exercise upon Plasma Total Homocysteine and Blood Lipid Concentrations

Abstract

The aim of the experiment was to find the effect of intermittent normobaric hypoxic exercise upon a group of young adults. Thirty male subjects aged eighteen to twenty-eight years old were weighed and sum of four skinfolds measured before and after four weeks of chronic exercise. A blood sample was taken at rest pre and post chronic exercise to ascertain their lipid profile, plasma total homocysteine, folate and vitamin B 12 levels. Each subject completed a seven day food and fluid intake pamphlet pre and post chronic exercise. Aerobic power was tested normoxically and hypoxically using an incremental cycle test to volitional exhaustion before chronic exercise and normoxically after chronic exercise. A blood sample was taken immediately post acute exercise to measure plasma total homocysteine concentration which was adjusted to take account of plasma volume shifts. Fourteen subjects exercised normoxically and sixteen subjects exercised hypoxically three times a week. The intensity and duration of the exercise sessions increased throughout the period from 70 to 85% and 20 to 30 minutes. The Normoxic group's normoxic acute cycle test significantly increased plasma total homocysteine concentration (+0.6±1.3 jimol.dm-3, p=0.035), whereas the hypoxic group's change was not significant (+0.2±1.2 umol.dm-3 , p=0.408). Normoxic chronic exercise significantly increased plasma homocysteine concentration (+1.2±1.0 umol.dm-3, p=0.002) whereas hypoxia showed no significant change (-0.4±1.7 umol.dm-3 , p=0.361).

The changes were not physiologically significant. Normoxic and hypoxic chronic exercise had no effect upon the subjects total cholesterol concentration (-0.51±0.51 mmol.dnr-3 ; -
0.32±0.52 mmol.dnr-3 , respectively, 2-way ANOVA p=0.339) nor upon their aerobic power (+3.2±4.8 cm3 .kg- 1 .min- 1 ; +5.1+10.9 cm3 .kg- 1 .min- 1 respectively, 2-way
ANOVA p=0.568). An advantage of training under hypoxic conditions is that it minimises the fluctuations in plasma total homocysteine concentration that would be obtained when training normoxically.

Date of Award	2003
Original language	English