While the Lief is sweat-proof, designed to handle sweat and splash, it cannot be immersed in water. Furthermore, the ECG stickers necessary to conduct the HRV readings will not maintain their adhesion to your body if too much moisture is introduced.

Thus, do NOT wear your Lief while showering, swimming, or engaging in other activities where you will be fully submerged in liquid, or perspiring so much that the stickers slide off your body.