Purpose Sperm quality and function are reduced by environmental factors (e.g., obesity), leading to increased infertility worldwide. Therefore, the purpose of this review paper was to investigate the effects of obesity and exercise training on sperm quality and function in animal and human models. Methods In order to determine the effects of obesity and exercise on sperm quality, motility, morphology, testosterone, oxidative stress, inflammation, we reviewed previous literatures with MEDLINE, PubMed, and Scopus databases. Results The most important factor to control the sperm motility is calcium ion, which is performed by the protein of CatSper (Cation Channel of Sperm). Obese men showed the decrease of number, concentration, motility, and volume in sperm, resulting in delayed or failed fertility. However, regular exercise training increased sperm-mediated factors including number, motility, and morphology, and festicular function-mediated factors including sperm concentration and serum testosterone. Conclusions While obesity exacerbates sperm quality and function in men, regular exercise training with moderate intensity increases sperm number and motility and reduces oxidative stress and inflammation, leading to the improvement of men’s fertility.
