NREM 2 is a deeper stage of sleep than NREM 1 and accounts for the largest portion of a typical night's rest. During this phase, body temperature drops, heart rate slows, and brain waves continue to decelerate. While very light dreaming or mental activity can occur here, NREM 2 is more about preparing the body and brain for deeper, restorative sleep rather than producing vivid dreams. Sleep spindles and K-complexes — brief bursts of brain activity — are common in this stage and are thought to play a role in memory and learning. Still, REM sleep is the primary stage linked with vivid and emotional dreaming, not NREM 2.