Experience after Floatation-REST: Relaxation during floating mediates the afterglow effect

The term "afterglow" originally described the heightened mood and relaxation following psychedelics and later extended to other altered states. Despite anecdotal reports, little research has explored this effect, especially in Floatation-REST (Reduced Environmental Stimulation Technique). In this method, individuals float in thermoneutral, supersaturated salt water in a dark, quiet tank. Using a crossover design, 34 participants (17 females, 17 males; avg. age 32.2, SD = 8.8) were randomized to 60 min of Floatation-REST or Bed-REST (a control condition on a waterbed). Floatation-REST induced significantly weaker body boundaries, significantly stronger time distortion, and significantly greater relaxation. Post-exposure, participants reported a significantly stronger afterglow, significantly more state mindfulness, and significantly greater interoceptive awareness. Mediation analysis showed relaxation during floating fully explains the afterglow effect. These findings align with psychedelic research, suggesting Floatation-REST elicits similar effects and laying the groundwork for future studies on prolonged afterglow experiences.