Lifestyle implications of the paradox and management of oxidative stress in sperm.

Oxidative stress (OS), defined by an imbalance between reactive oxygen species (ROS) production and antioxidant defences, plays a bivalent and paradoxical role in the male reproductive system. At physiological levels, ROS are indispensable for sperm capacitation, hyperactivation and acrosome reaction, which are crucial for fertilization. However, excessive ROS - stemming from both endogenous sources (e.g. mitochondrial metabolism, enzyme-mediated reactions, seminal leukocytes) and exogenous factors (e.g. environmental pollutants and lifestyle behaviours) - can trigger detrimental OS reactions, including lipid peroxidation, DNA damage and impaired sperm function, contributing to male infertility. This dualistic nature of OS complicates defining the distinction between its physiological and pathological concentrations of ROS. This review comprehensively examines the complex interplay between ROS and OS in male reproduction, delineating how lifestyle factors can contribute to this imbalance and what mechanisms are implicated. Furthermore, we discuss current and emerging non-pharmacological strategies aimed at mitigating pathological OS, including antioxidant supplementation (e.g. resveratrol, vitamins C and E, coenzyme Q10), dietary interventions such as adherence to the Mediterranean diet and lifestyle modifications like regular moderate exercise and stress management techniques. By elucidating these multifaceted aspects, our analysis provides critical insights into maintaining redox homeostasis and advancing clinical interventions for improved male reproductive health.