Effect of endurance training on blood variables and maximal oxygen uptake: An 8-week intervention study on untrained subjects

Abstract

Aim: To investigate how blood variables and maximum oxygen uptake (VO2max) adapt to 8-weeks of endurance training in a group of untrained subjects and compare the findings with a group of endurance trained subjects. The study also wanted to investigate the relationship between blood volume (BV), hemoglobin mass (Hb-mass) and VO2max.

Method: 8 untrained women (n=5) and men (n=3) (INT) underwent 8 weeks (3/week) of endurance training, while 7 trained women (n=3) and men (n=4) served as controls (CON). Various tests on blood and performance variables was carried out pre-, mid- and post the 8-weeks of endurance training.

Results: INT increased BV (3.8 ± 1.5%), Hb-mass (4.8 ± 1.4%), plasma volume (PV) (4.2 ± 1.9%) and VO2max (11.4 ± 2.9 %). Changes in BV seems to be related to changes in PV. CON increased Hb-mass (4.8%) and hemoglobin concentration [Hb] (3.7%), while BV and VO2max, remained unchanged. There was a difference in BV, PV and VO2max between the groups at pretest, but no differences were shown at posttest. There was a correlation between Hb-mass and VO2max, but the correlation was lower in INT compared to CON. BV and VO2max correlated only in CON.

Conclusion: These data indicate that 8-weeks of endurance training improve BV, Hb-mass, VO2max and PV in untrained subjects.