Data from the World Health Organization (2001) and the United States Department of Health and Human Services (1996) show that more and more adults are suffering from depression at least once in their lifetime. In terms of health costs, 10% of these are related to mental health problems. These disorders represent the fourth largest cause of disability. The data allow us to understand how important it is to act at the population level as a way of improving emotions and negative moods.

Several studies prove the benefits of physical exercise on psychological well-being. Acute exercise sessions improve moods by decreasing feelings of anxiety, depression, anger, and increasing feelings of arousal, energy, and alertness (Werneck, 2006). These benefits can last hours after exercise and even become chronic if repeated over time. This idea is corroborated by several authors who add that even in the absence of a regular exercise practice, a small volume of physical activity can bring benefits in the moods of practitioners (Stewar et al., 2003). Physical exercise is equated with psychotherapeutic and pharmacological treatments, in decreasing anxiety and depression, respectively, and has the advantage of being more beneficial to patients, both economically, as well as their health and adherence level (Craft & Landers, 1998).

At the level of the mechanisms of physical activity and how they influence emotions and moods, there are not enough studies to create a consensus, both in terms of intensity and type of physical activity. Regarding the type of physical activity, aerobic exercise and strength exercise positively alter mood states. Aerobic exercise is more effective in reducing anxiety than strength exercise. (Gaarvin, Koltyn & Morgan, 1997). In order for the exercise mood to be optimized, it should be pleasant, aerobic, non-competitive, moderate in intensity, lasting at least 20 to 30 minutes and should be practiced indoors at a pre-defined time ( Berger & Molt, 2000).

 Regarding the type of physical activity, studies showed that individuals who practiced outdoor physical activity, compared to indoor, had more positive effects on psychological well-being. Exercise in natural spaces is related to the increase in positive mood states (Coon et al., 2011). A study of over 20,000 Australians has shown that green environments enhance practitioners' well-being. Research has shown that when individuals are exposed to a mere five minutes in natural spaces there are benefits to their mental health regardless of the age and gender of the individuals.

Knowing that both emotions and moods have a momentary and transient character, and both derive from the individual's experiences, we realize that with our work in the area of ​​exercise and health we can provide empowering experiences in order to positively influence emotions and moods, and thus improve the health and well-being of individuals. Start exercising and let go of stress and negative emotions!

Ana Rita Cativo