**1. Introduction**

Substantial evidence is that sedentary behavior associated with the so-called modern lifestyle increases the risk of obesity, cardiovascular disease, type 2 diabetes, osteoporosis, cancer, and depression. However, it is commonly thought that increasing the level of physical activity (PA) plays an essential role in preventing, reducing, managing, and treating these diseases with a wide variety of pathologies [1]. Although an active lifestyle has always been accepted as the best way to achieve health throughout civilization's history, since Hippocrates prescribed exercise for the first time in a patient, the concept of exercise as a medicine or a preventive method has been increasingly accepted in the last two decades [2–4]. Current studies report

that exercise has a "polypill" feature with very low cost, no adverse effects, and nonpharmacological and easily accessible advantages compared to drugs, surgery, and hospitalization [5, 6].

The literature on the beneficial effects of exercise on health has generally focused on cardiovascular outcomes. However, studies pointed out that regular exercise can improve mental and physical health [7, 8]. According to Kramer [9], exercise acts like a drug with many beneficial effects. It should be prescribed not only for physical but also for mental health [9]. Several clinical studies [10–12] reported that exercise might trigger positive effects on different mental diseases, e.g., major depressive disorders (MDD), Alzheimer's dementia, and schizophrenia (SZ). While exercise facilitates adaptations to individuals' stress response systems, it can also improve physiological impairments imposed by psychological stressors [13]. Indeed, high levels of PA have been shown to reduce the risk of depression [14] and anxiety [15]. Many studies have shown that exercise can offer benefits comparable to antidepressant drugs in patients with depression [10, 16]. Similarly, current studies show that moderate to highintensity daily exercises positively affect mental health, adversely affected by social isolation due to the pandemic [17].

The central questions that remain to be answered are whether or how exerciseinduced neurotrophic factors impact mental health. Although many studies' results from the last decades have improved our understanding of the highly complex neurobiological and cognitive underlying mechanisms of mental health induced by exercise, many gray areas remain to be answered [18]. The putative idea that exercise can affect cognitive and behavioral functions positively has been extensively studied since the study of Van Praag et al., [19] allowing us to obtain cumulative information [19]. The pioneering study of Dishman et al. [20] showed for the first time that the prevention and treatment of diseases (including mental disorders) could be achieved through exercise-induced neurobiological mechanisms [20]. Today, exercise is thought to benefit mental health by mediating biochemical and physiological changes such as increased neurogenesis and decreased inflammatory and oxidant markers [21]. It is widely accepted that exercise, depending on the type, duration, and frequency, can trigger such benefits by increasing the levels of neuroprotective factors such as BDNF, irisin, vascular endothelial growth factor (VEGF), and insulin-like growth factor-1 (IGF-1) in the circulation or brain [22–24].

The relationship between the levels of these molecules (especially in the blood) and postexercise brain function may help identify biomarkers that can serve as objective indicators for clinically evaluating exercise therapy in the diseased or particularly aging brain. In addition, a better understanding of biomarkers may be instrumental in elucidating the mechanisms that mediate exercise-induced mental health. Thus, it can contribute to the discovery of new drugs or the creation of more effective exercise prescriptions for treatments to protect mental health. Due to the heterogeneous effect of exercise (exercise variables or levels of physical fitness and health status of person), it is, unfortunately, difficult to individualize an exercise regimen with optimal effects on mental health. Therefore, more research is needed to maximize the benefits of exercise to counter mental illness. Considering that there is currently no pharmaceutical drug or invasive method to treat neurodegenerative diseases, it will be important to evaluate the powerful potential of exercise to cope with neurodegenerative diseases [25].

In this regard, this paper aimed to summarize recent findings on candidate neurotrophic factors linked with mental health that exercise affects. It also focuses on identifying which exercise regime is an essential mediator of mental health and *The Potential Role of Exercise-Induced Neurotrophic Factors for Mental Health DOI: http://dx.doi.org/10.5772/intechopen.106867*

discuss whether there could be a generalized exercise prescription for optimizing mental health.
