A Review Article on Aging and Age-Related Disorders

Aging is a complex, progressive biological process characterized by a gradual decline in physiological reserve, impaired ability to maintain homeostasis, and increased susceptibility to disease and death. It results from interacting molecular, cellular, genetic, environmental, and lifestyle factors rather than from a single mechanism. Modern aging biology describes interconnected hallmarks of aging, including genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, impaired autophagy, mitochondrial dysfunction, deregulated nutrient sensing, cellular senescence, stem-cell exhaustion, altered intercellular communication, chronic inflammation, and microbiome alterations. Age-related disorders include cardiovascular disease, stroke, cancer, osteoporosis, osteoarthritis, sarcopenia, diabetes, chronic respiratory disease, neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease, sensory impairment, depression, frailty, falls, and other geriatric syndromes. Importantly, aging itself is not synonymous with disease: healthy aging focuses on preserving functional ability and quality of life, even when chronic diseases are present.