During high-intensity workouts, several physiological responses occur, including increased heart rate, elevated body temperature, and enhanced energy metabolism. The body requires more oxygen to meet the energy demands, leading to greater respiratory rates. The release of adrenaline and other hormones during intense exercise triggers the breakdown of stored glycogen and fat for energy. Additionally, muscle fibers experience micro-tears, prompting repair and growth in the recovery phase. These combined effects contribute to improved strength, endurance, and fitness, highlighting the body's adaptation to short bursts of vigorous activity.