Feed your mind.
Learning is an important aspect of mental fitness, and thankfully there are a growing number of research articles on the topic:
General Mental Fitness
The importance of mental fitness
by Erica Roth and Dr. Timothy Legg / Healthline Media
Three keys to optimum mental fitness
by Clifford Lazarus, Ph.D. / Psychology Today
Ten tips to improve your mental fitness
Department of Health & Human Services in Victoria, Australia
Twenty top tips for mental fitness
by Jennifer A. Brush, MA, CCC/SLP
Cultivating mental fitness
by Flor Sylvester / A Lust for Life
Creativity + Fitness
Creative thinking and the brain
with Shelley Carson / Harvard Health Letter
Exercise effects on the mind and creativity
by Kevin Loria / Business Insider
Seven surprising facts about creativity
by John Paul Titlow / FastCompany
Hormones + Neurochemicals
Hormones that make you happy
by M. Farouk Radwan, MSC / 2KnowMyself.com
The neurochemicals of happiness
by Christopher Bergland / Psychology Today
Neuroplasticity
How plastic is the brain?
by Angela Chen / The Verge
Sleep
How to get a good night's sleep
by Sean Illing / Vox
Technostress
How technology is hijacking your mind
by Tristan Harris / Medium
Related Research
Self-Determination Theory (Ryan, R. M., & Deci, E. L., 1980-2017)
Mindfulness and bodily distress (Fjorback LO., 2012)
Mindfulness interventions (Creswell JD et al., 2017)
Mindfulness-based interventions for anxiety and depression (Hofmann SG, Gómez AF., 2017)
Psychological Needs and the Facilitation of Integrative Processes (Ryan, 1995)
National & International Resources
Canadian Mental Health Association
Cleveland Clinic: Healthy Brains (US)