Heat Suit Training Preserves the Increased Hemoglobin Mass after Altitude Camp in Elite Cyclists

Purpose: Altitude training is a common strategy used with the intent to increase hemoglobin mass (Hb(mass)) in athletes. However, if the Hb(mass) is increased during altitude camps, it seems to decline rapidly upon returning to sea level. This study aimed to examine the efficacy of three weekly heat training sessions over a 3.5-wk period after a 3-wk altitude camp on the maintenance of Hb(mass) in elite cyclists. Methods: Eighteen male cyclists (maximal oxygen consumption: 76 +/- 5 mL center dot min(-1)center dot kg(-1)) underwent a 3-wk altitude training camp at similar to 2100 m above sea level. After the camp, participants were divided into one group performing three weekly heat sessions that were subtracted from their usual training (HEAT) while the other continuing usual training (CON). Training characteristics were recorded during the intervention, whereas hematological measurements were recorded before the camp as well as 2 d and 3.5 wk after the altitude camp. Results: The 3-wk altitude camp led to an overall increase in total Hb(mass) of 4.1%. Afterward, HEAT maintained Hb(mass) (0.2%, P = 0.738), whereas CON group experienced a significant reduction (-3.3%, P < 0.001) (Delta HEAT vs Delta CON, P < 0.001). Moreover, HEAT increased plasma volume (PV) by 11.6% (P = 0.007) and blood volume (BV) by 5.8% (P = 0.007), whereas CON only showed an increase in PV (5.5%, P = 0.041). Exercise intensity and training load were not different between groups during the maintenance period. Conclusions: This study suggests that incorporating three weekly heat training sessions into the usual training routine preserves a moderately increased Hb(mass) in elite cyclists after an altitude camp.