Stress significantly impacts physical health and fitness performance by triggering physiological responses that can lead to issues such as increased cortisol levels. High stress can result in muscle tension, fatigue, and even injuries due to decreased attention and focus during workouts. Additionally, chronic stress may lead to unhealthy coping mechanisms, such as overeating or neglecting exercise. Therefore, managing stress through practices like mindfulness, meditation, and regular physical activity is vital for maintaining optimal health and performance.