**2. Deal with mental health conditions**

In response to the impact caused by mental health conditions, the World Health Organization Mental Health Action Plan (2013–2030) aims to focus on four major objectives "more effective leadership and governance for mental health; the provision of comprehensive, integrated mental health and social care services in communitybased settings; implementation of strategies for promotion and prevention; and strengthened information systems, evidence and research". This is a great effort to improve mental health, but much more needs to be done, especially considering lowand middle-income countries [9]. In general, mental health conditions can be treated at a relatively low cost; however, the gap between people needing care and those with access to care remains substantial.

Each mental health condition needs special attention to choose the best available treatment. Evidence has shown that lifestyle factors (physical activity, diet, tobacco smoking, and sleep) influence different psychiatric conditions. A meta-review concerning the role of modifiable lifestyle factors in preventing and treating mental disorders confirms that physical activity has a protective role in reducing the risk for certain mental disorders [10]. Physical activity provides effective adjunctive treatment for depression, anxiety and stress-related disorders, psychotic disorders, and attention-deficit/hyperactivity disorder (ADHD) [10]. Poor sleep has a causal role in bipolar disorder, and sleep disturbances have been found to significantly heighten the risk of suicidal behaviour in people with mental illness [10]. Smoking is associated with a heightened prospective risk of mental disorders, earlier age of onset, and adverse outcomes in those living with mental illness [10]. The causal effects of diet on common and severe mental conditions are less clear.

It is well recognised the effects of physical activity and exercise (structured physical activity) on several health outcomes, such as improvements in longevity, bone mineral density, cardiovascular risk factor, aerobic fitness, muscular strength and endurance, diabetes mellitus, obesity, some types of cancers, osteoporosis, and mental health [11]. Therefore, it is important to understand the association between physical activity and mental health conditions.
