Sweat rate is a critical physiological parameter that varies across different sports and environmental conditions, directly influencing athletic performance, hydration strategies, and the risk of heat-related illnesses. This chapter presents detailed methods for assessing sweat rate getting used in various sports with distinct physical demands and environmental conditions. The gravimetric method (pre-post weighing) remains the most widely used technique due to its simplicity and reliability. Other methods, such as sweat patches, bioelectrical impedance analysis, microfluidic-based, and hygrometer-based wearable sweat sensors, offer specific advantages in controlled or dynamic environments, allowing real-time monitoring of fluid loss. This chapter aims to serve as a comprehensive resource for sports scientists, physiologists, and coaches working to enhance performance and safeguard athlete health through the monitoring of sweat loss.