Ever wondered what your heart is actually doing while you're exploring 60 feet beneath the surface? In this episode, Ray Hollister draws on four decades of diving experience to explain how modern dive computers can now track your pulse underwater and why that matters for your safety. Whether you're a recreational diver curious about the latest tech or a seasoned veteran wondering if heart rate monitoring is worth the investment, this guide breaks down the science, the limitations, and the practical value of this evolving technology.

• Heart rate monitoring dive computers use optical PPG sensors built into the case back, not chest straps, shining LED light into your skin to detect blood volume changes with each heartbeat and sampling 50 to 100 times per second.

• Cold water creates real challenges for accuracy—vasocon ...