There is growing evidence illustrating the negative aspects of reinvestment on everyday life, however its underlying mechanisms remain unclear. The main aim of this study was to empirically clarify the relationship between reinvestment and working memory (WM). A secondary aim was to investigate the contribution of high-frequency heart rate variability (HF-HRV) to WM. Sixty-two participants took part in a within-subject design in which we measured their WM capacity in a low-pressure and a high-pressure condition while their HF-HRV was measured. In addition, they had to fill out scales assessing their dispositional reinvestment. Results showed that the correlation between reinvestment and WM is negative, exists only in the high-pressure condition, and is specific to the decision component of reinvestment and not the movement component. Moreover, a hierarchical regression analysis revealed that under high pressure resting HF-HRV predicted WM performance above DSRS, whereas DSRS did not predict WM performance above resting HF-HRV.