HRM 600

The Garmin HRM 600 is a chest strap that records a session on its own, which is what separates it from a strap that only relays to a watch. The module stores the workout and syncs to the Garmin Connect app afterwards, so training runs with no watch on the wrist at all.

The module weighs 18 grams and the strap and module together weigh 61 grams in the M-XL size. It is rated to 5 ATM and runs up to two months on a lithium-ion cell at an hour of use a day. Data transmits over ANT and Bluetooth Low Energy at the same time, so a watch and a second device both receive it. The module detaches and the strap goes in a washing machine.

The result is heart rate and heart rate variability a wrist sensor cannot match, which is the point of a strap for anyone training between dive trips. A tri-colour status LED confirms the strap is reading before the session starts, and running dynamics reach a compatible Garmin watch alongside the heart rate. Swim data syncs once the module is back in range.

Two strap sizes cover most fits, XS-S and M-XL, each carrying the same module. The 5 ATM rating covers swimming and surface water use. This is not a dive-rated device and does not go on a scuba dive; it pairs with the Descent range for surface training and dry-land conditioning.