Physiological changes occur with aging that affect nearly every system of the body. The skin shows signs of aging like wrinkling due to loss of fat and muscle beneath. Bones weaken due to loss of density, increasing risks like osteoporosis and fractures. Muscle mass declines as well. Internally, the heart and lungs lose elasticity over time, and kidney and digestive function declines. Hormone production also wanes with age. These universal changes are gradual and inevitable parts of the aging process for all humans.