Excessive screen time can lead to a range of negative physical health effects, including obesity due to decreased physical activity and poor posture from prolonged sitting. It can also result in eye strain, often referred to as "computer vision syndrome," which causes discomfort and fatigue. Additionally, prolonged screen use may disrupt sleep patterns due to exposure to blue light, leading to fatigue and associated health issues. Overall, balancing screen time with physical activity is crucial for maintaining optimal health.