Aging impacts physical fitness levels primarily due to physiological changes such as decreased muscle mass, reduced bone density, and slower metabolic rates. These factors can contribute to a decline in strength, flexibility, and endurance, making it more challenging for older adults to engage in physical activities. However, regular exercise can mitigate these effects by promoting muscle strength, enhancing balance, and improving cardiovascular health. Staying physically active is crucial for maintaining a higher quality of life and reducing the risks of age-related diseases, such as osteoporosis and heart disease.