Most people today would agree that health is not a one-dimensional experience. Commonly accepted definitions of health, such as that put forward by the World Health Organisation, incorporate physical, mental and social aspects of health. It follows that being healthy does not just mean being physically fit. Being of sound mind is also important, as is social wellness or the ability to form and maintain a network of friends and associates. Some would add spiritual health as another aspect of wellbeing. But what is the relationship between these components of health, and what is the implication of being strong in one area and/or lacking in another. In particular, what is the connection between mental and physical health and what does "healthy body, healthy mind" really mean ?
It is common to consider aspects of health as interdependent; that is, each element influences the other. Practitioners using this type of health model would look at the balance between aspects of health when assessing wellbeing. They may suggest activity in one realm to offset an over-emphasis in another. For example, someone who is working long hours in an office expending much mental energy and heading toward "burnout" may be advised to incorporate more physical exercise into his/her lifestyle in order to bring the wellness system into balance. This may seem like a simple remedy, but the implications can be quite profound. Making even a small effort in a (previously) neglected realm often results in a much more balanced perspective. By taking some time out to work on the physical aspect of health the mind gets a well-earned break and would most likely return to work refreshed and invigorated. Within this framework a balance of the health components is advocated and over-attention to one component of health is not.
It is generally accepted that there is a relationship between physical and mental health. Many athletes would agree that it takes a great deal of mental effort to sustain physical performance. You need only think of a momentary lapse in concentration, say in a game of tennis; to see how closely related the mental and physical aspects of sporting performance are. Although the impact of the mind on physical performance is generally accepted the influence of physical activity on mental health is not as widely acknowledged or understood. There has, however, been research supporting the notion that physical activity has the capacity to enhance mental health. Physical activity had been linked to a host of outcomes including positive mood, lower levels of depression and elevated alertness and concentration. Many would attribute these associations to chemical changes occurring within the body when physical exercise is performed. Other explanations are less direct and implicate factors such as the social aspects of exercise or the sense of mastery achieved in participating in sport. Although there is definitely some relationship between physical health and mental health, the pathways between the two are not yet fully understood.
It is important to keep in mind that the positive impact of physical exercise on mental health or wellbeing is relevant for mental health but not necessary mental ill-health. It would be unlikely that someone suffering from a mental illness, such as schizophrenia, would be prescribed exercise as a remedy. If it was as simple as physical health = mental health, there would be little need for psychologists. However, most health practitioners would agree that physical exercise is often a useful adjunct to therapy for mild mental conditions where physical exercise has been linked to positive treatment outcomes.