Sprint interval training in the postpartum period maintains the enhanced cardiac output of pregnancy: A case study.

During pregnancy an increased cardiac output ( ) and blood volume (BV) occur to support fetal growth. Increased and BV also occur during chronic endurance exercise training and benefit performance. We investigated if sprint interval training (SIT) undertaken early postpartum maintains the elevated and BV of pregnancy and benefits performance. The participant, a competitive field hockey player and former cyclist, visited our laboratory at 2 weeks of gestation (baseline) and postpartum pre-, mid- and post-intervention (PP, PP and PP). Delivery was uncomplicated and she felt ready to start the SIT programme 5 weeks postpartum. Inert gas rebreathing was used to measure peak exercise ( ); was measured with a metabolic cart; and postpartum haematological values were measured with carbon monoxide rebreathing. The 18 SIT sessions progressed from four to eight sprints at 130% of peak power output. increased from baseline at all postpartum time points (baseline 16.2 vs. 17.5, 16.8 and 17.2 L/min at PP, PP and PP, respectively). Relative remained below baseline values at all postpartum measurements (baseline 44.9 vs. 41.0, 42.3 and 42.5 mL/kg/min at PP, PP and PP, respectively) whereas absolute rapidly reached baseline values postpartum (baseline 3.19 vs. 3.12, 3.23 and 3.18 L/min at PP, PP and PP, respectively). Postpartum BV (5257, 4271 and 5214 mL at PP, PP and PP, respectively) and Hb (654, 525 and 641 g at PP, PP and PP, respectively) were similar between PP and PP but decreased alongside at PP. Peak power was returned to pre-pregnancy values by intervention end (302 vs. 303 W, baseline vs. PP). These findings show that SIT undertaken early postpartum defends the elevated of pregnancy and rapidly returns absolute and peak power to baseline levels.