Five weeks of heat training increases haemoglobin mass in elite cyclists

Abstract

In this study we tested the hypothesis that performing 1 h of regular light exercise in a heat chamber (HEAT; 37.8 ± 0.5 • C; 65.4 ± 1.8% humidity) 5 times week −1 for a total of 5 weeks increases haemoglobin mass (Hb mass) and exercise performance in elite cyclists (V O 2 max = 76.2 ± 7.6 ml min −1 kg −1). Twenty-three male volunteers were assigned to HEAT (n = 11) or CON (n = 12; 15.5 ± 0.1 • C; 25.1 ± 0.0% humidity) training groups. Hb mass was determined before and after the intervention period in conjunction with an extensive exercise test protocol (conducted at 16-19 • C). HEAT increased (P < 0.05) Hb mass by 42 g from 893 ± 78 to 935 ± 108 g whereas Hb mass remained unchanged (+6 g) in CON. Furthermore, statistical analysis revealed a time-group interaction (P < 0.05). The greater increase in Hb mass in HEAT, however, did not manifest in a greater increase inV O 2 max (225 ± 274 ml min −1 in HEAT and 161 ± 202 ml min −1 in CON). While HEAT reduced (P < 0.05) lactate levels during some of the submaximal exercise tests, there was no statistical difference between other performance parameters. There were, however, small to intermediate effect sizes favouring HEAT for lactate threshold power output (2.8 ± 3.9 vs. −0.4 ± 5.1% change, effect size (ES) = 0.34), gross economy in the fatigued state (0.19 ± 0.42 vs. −0.12 ± 0.49%-point change, ES = 0.52) and 15 min mean power (6.9 ± 8.4 vs. 3.4 ± 5.1% increase, ES = 0.22). This study demonstrates an increase in Hb mass and small to intermediate effect sizes on exercise variables in elite cyclists following a 5-week heat training intervention. K E Y W O R D S blood volume, exercise, hot environment 1 INTRODUCTION A high maximal oxygen uptake (V O 2 max) is essential for successful exercise performance in endurance sport disciplines. WhileV O 2 max is the product of the Fick equation in which both O 2 transport to the exercising skeletal muscles and O 2 extraction by the skeletal muscle contribute, the biggest difference between individuals with This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

The Influence of Training Load on Hematological Athlete Biological Passport Variables in Elite Cyclists

“…Venous blood was drawn from an antecubital vein and immediately analyzed in triplicate for HbCO% with a calibrated gasometer (ABL80-Co-Ox, Radiometer, Copenhagen, Denmark). Initial duplicate measurements in our laboratory yielded a typical error (TE) of 1.8% for Hbmass, in line with previously reported values (Siebenmann et al, 2017;Rønnestad et al, 2020). The CO remaining in the system was measured with a CO meter (Monoxor Plus, Bacharach, New Kensington, USA) and subtracted from the initial amount introduced to define the exact CO bolus received with a 0.1 mL typical error.…”

The influence of training load on hematological Athlete Biological Passport variables in elite cyclists

“…Venous blood was then drawn from an antecubital vein and immediately analyzed in triplicate for carboxyhemoglobin content (HbCO%) with a calibrated gasometer (ABL80-Co-Ox, Radiometer, Copenhagen, Denmark). Initial duplicate measurements in our laboratory yielded a typical error (TE) of 1.8%, in line with previously reported values (Siebenmann et al, 2017;Rønnestad et al, 2020). The CO remaining in the system was measured with a CO meter (Monoxor Plus, Bacharach, New Kensington, USA) and subtracted from the initial amount introduced to define the exact CO bolus received with a 0.1 mL typical error.…”

Intermittent post-exercise sauna bathing improves markers of exercise capacity in hot and temperate conditions in trained middle-distance runners

“…The 8% mean improvement in VO 2max observed in the current study (~ 6% more than the CON group) is comparable to the 5% observed by Lorenzo and colleagues (2010) when using a 10-day active heat acclimation protocol. Possible mechanisms facilitating this improvement in aerobic capacity with heat acclimation include a greater maximum cardiac output, as demonstrated by Lorenzo et al (2010) in their study, or increases in total haemoglobin mass, which are possible in an intervention stretching over multiple weeks, as more recently demonstrated by Rønnestad et al (2020). The iron supplements given to participants in the current study may have helped to facilitate improvements in oxygen carrying capacity, though participants were not given iron supplements by Rønnestad et al (2020) or by Scoon et al (2007), who both observed haematological adaptations following heat acclimation.…”