RADS measures your level of radiation exposure. It is gained from two sources:

Each point of RADS effectively reduces your maximum HP by 1. If your RADS becomes greater than or equal to your maximum HP, you will begin 💀 Dying. The RADS have to be reduced to below your maximum HP to save you from 💀 Death.

RADS can be reduced by ☢️ RadAway, doctor visits, and certain perks.