Short N2 sleep 2023-07-28T13:55:40Z Short subdued state of NREM Decreased duration of phase N2 of nonrapid eye movement (NREM) sleep. In the N2 sleep stage, muscles begin to relax, breathing and heart rate slow, and body temperature drops slightly. During this stage of the sleep cycle, your brain activity also slows down to help maintain sleep. Short NREM sleep