Larger splenic emptying correlate with slower EPOC kinetics in healthy men and women during supine cycling

Purpose The present study investigated whether larger splenic emptying augments faster excess post-exercise O-2 consumption (EPOC) following aerobic exercise cessation. Methods Fifteen healthy participants (age 24 +/- 4, 47% women) completed 3 laboratory visits at least 48-h apart. After obtaining medical clearance and familiarizing themselves with the test, they performed a ramp-incremental test in the supine position until task failure. At their final visit, they completed three step-transition tests from 20 W to a moderate-intensity power output (PO), equivalent to <(V)over dot>O-2 at 90% gas exchange threshold, where data on metabolic, cardiovascular, and splenic responses were recorded simultaneously. After step-transition test cessation, EPOCfast was recorded, and the first 10 min of the recovery period was used for further analysis. Blood samples were collected before and immediately after the end of exercise. Results In response to moderate-intensity supine cycling (<(V)over dot>O-2 = similar to 2.1 L.min(-1)), a decrease in spleen volume of similar to 5% (p = 0.001) was observed, resulting in a transient increase in red cell count of similar to 3-4% (p = 0.001) in mixed venous blood. In parallel, mean blood pressure, heart rate, and stroke volume increased by 30-100%, respectively. During recovery, mean tau<(V)over dot>O-2 was 45 +/- 18 s, the amplitude was 2.4 +/- 0.5 L.min(-1), and EPOCfast was 1.69 -L.O-2. Significant correlations were observed between the percent change in spleen volume and (i) EPOCfast (r = - 0.657, p = 0.008) and (ii) tau<(V)over dot>O-2 (r = - 0.619, p = 0.008), but not between the change in spleen volume and (iii) <(V)over dot>O-2 peak (r = 0.435, p = 0.105). Conclusion Apparently, during supine cycling, individuals with larger spleen emptying tend to have slower <(V)over dot>O-2 recovery kinetics and a greater EPOCfast.

Automated summary

This study investigated whether larger splenic emptying enhances excess post-exercise O-2 consumption (EPOC) after aerobic exercise cessation. It was found that during moderate-intensity supine cycling, spleen volume decreased by about 5%, resulting in a transient increase in red cell count and an increase in cardiovascular variables. Significant correlations were observed between the percent change in spleen volume and both EPOCfast and tau<(V)over dot>O-2.