Mental health problems have been major public health concerns in youth, young adults, and older adults. Mental health challenges are leading causes for school and college students to experience academic struggles in school and psychosocial problems in daily life. Likewise, mental health problems negatively influence the quality of life and independence of elderlies. It is well documented that regular physical activity (PA) is essential to preventing and alleviating mental health problems, and to improving mental health and well-being across the lifespan.

However, most school children, college students, and older adults do not engage in the recommended daily physical activity. Thus, there is an urgent need for assessing the effects of PA on mental health and well-being across the lifespan and developing innovative approaches to promoting PA, mental health, and well-being.

The aim of this Special Issue is to bring together original research articles and review articles that examine the relationships between physical activity, mental health, and well-being. We hope that this Special Issue will highlight the effects of combining innovative technology with physical activity to improve mental health and well-being.

Potential topics include but are not limited to the following:

• Associations of type and intensity levels of physical activity with mental health and well-being of a targeted population with or without chronic conditions
• Identifying mediators and moderators of the relationship between physical activity and mental health of a targeted population
• Identifying factors that contribute to developing and maintaining healthy lifestyles of a targeted population
• Identifying factors that contribute to developing and improving mental health and well-being of a targeted population
• Effects of healthy lifestyle interventions on increasing physical activity, mental health, and/or well-being of a targeted population
• Feasibility of implementing physical and mental health interventions using mixed-methods approaches
• Effects of technology-enhanced lifestyle interventions on improving physical activity, mental health, and well-being of a targeted population
• Effectiveness of a virtual intervention program promoting physical activity, mental health, and well-being of a targeted population