Evaluating a Mat-Based Biometric Vibration System for Sleep and Daily Recovery

Inclusion Criteria: * Adults 18-45 years. * Able to provide written informed consent. * Apparently healthy and free of unstable cardiovascular, neurological, or psychiatric conditions per screening. * Cleared for low-to-moderate intensity whole-body vibration delivered supine/recumbent on a mat. * Willing and able to comply with study procedures: two lab visits; 3-week home protocol (3-4 days/week); three 15-min sessions; brief affect check-ins and daily logs. * Willing to abstain from caffeine, alcohol, and strenuous exercise for 24 hours before each lab visit and to attend visits at the same time of day. * Able to lie supine for 15 minutes and follow instructions for the HRV device. Exclusion Criteria: * Implanted electronic medical devices (e.g., pacemaker, neurostimulator). * Uncontrolled hypertension or severe vestibular disorders. * Current substance dependence. * Medications known to markedly affect autonomic function or sleep architecture (e.g., beta-blockers, antiarrhythmics, sedative-hypnotics, antidepressants with strong autonomic effects). * Diagnosed neurological or psychological disorders that substantially affect emotional processing or autonomic regulation (severe psychiatric conditions). * Prior extensive experience with vibration therapies (to minimize expectancy bias). * Any condition judged by study staff to contraindicate vibration exposure or preclude safe participation (including inability to tolerate supine/recumbent position). * Unwillingness to refrain from initiating new structured exercise or relaxation programs during the study period.