Increase interval training intensity improves plasma volume variations and aerobic performances in response to intermittent exercise

Abstract

PurposeWe studied the effect of two interval training programs of varying intensities (100% vs. 110% of maximal aerobic velocity [MAV]) on hematocrit (Ht), hemoglobin (Hb), and plasma volume variations (PVV) in young men. MethodsThirty-nine male volunteered were assigned to two control groups (CG100, n = 9 and CG110, n = 10), and two training groups (one with 100% MAV [EG100, n = 10] and one with 110% MAV [EG110, n = 10]). All participants performed a maximal graded exercise test and an intermittent exercise (IE) protocol. Blood was collected at rest, at the end of the IE and after 15 min of recovery, before and after 8-weeks-training. Interval training (IT) sessions consist of 30s IE run at 100% or 110% MAV with 30s recovery at 50% MAV. ResultsAfter training, time to exhaustion (TTE) was improved in EG110 (+613.7) and EG100 (+397.5). This improvement was greater in EG110 than EG100 (p < 0.005). After training, Hb deceased in EG100 and EG110 at rest (p < 0.01), at the end of IE (p = 0.000) and after 15 min of recovery (p = 0.01). This decrease was more slightly more substantial at rest in EG100 (−0.6%) than EG110 (−0.3%). After training, Ht decreased in EG100 and EG110 at rest (p = 0.001), at the end of IE (p = 0.000) and at 15 min of recovery (p = 0.01). This decrease was more important in EG110 than EG100 at rest (−2.7%), at the end of IE (−2.1%) and after 15 min recovery. After training, PVVrest and PVVend increased in EG100 (+2.2%) and EG110 (+3.2%). No significant difference between EG100 and EG110 was observed. ConclusionIncreasing IT intensity by 10% MAV increases PVVrest and PVVend. Despite the fact that EG100 and EG110 had the same PVVend after training, greater performances were recorded in EG110.