Could "cellular exercise" be the missing ingredient in a healthy life? Diets, caloric restriction, and exercise-induced hormesis.

Overnutrition is a poor dietary habit that has been correlated with increased health risks, especially in the developed world. This leads to an imbalance between energy storage and energy breakdown. Many biochemical processes involving hormones are involved in conveying the excess of energy into pathologic states, mainly atherosclerosis, hypertension, cardiovascular diseases, and diabetes. Diverse modalities of regular exercise have been shown to be beneficial, to varying extents, in overcoming the overnutrition comorbidities. Cellular exercises and hormesis are triggered by dietary protocols that could underlie the cellular mechanisms involved in modulating the deleterious effects of overnutrition through activation of specific cellular signal pathways. Of interest are the oxidative stress signaling, nuclear factor erythroid-2, insulin-like growth factor-1, AMP-activated protein kinase as well as sirtuins and nuclear factor-κB. Therefore, the value of intermittent fasting diets as well as different diet regimens inducing hormesis are evaluated in terms of their beneficial effects on health and longevity. In parallel, important effects of diets on the immune system are explored as essential components that can undermine the overall health outcome. Additionally, the subtle but relevant relation between diet and sleep is investigated for its impact on the cardiovascular system and quality of life. The aim of this review is to focus on how calorie restriction triggers multiple molecular pathways that ultimately lead to hormetic effects resulting in cell longevity and resistance to cardiovascular disease, stroke, and cancer.