14/03/2026
1. Bressan & Crippa, 2005 — dopamine / reward
2. Schultz, 2010 — dopamine reward signals
3. Volkow et al., 2011 — reward dysregulation / addiction
4. Dishman et al., 2006 — neurobiology of exercise
5. Harber & Sutton, 1984 — endorphins and exercise
6. Levenson et al., 2017 — social media use and sleep disturbance