Aging: Why We Age

Aging is a universal biological process, yet its underlying mechanisms remain widely misunderstood. Understanding why we age is not merely an academic pursuit—it clarifies what interventions can realistically slow decline and which longevity claims are unsupported. This course equips you with the scientific literacy to distinguish evidence from hype. The programme systematically unpacks four core drivers of aging. You will examine telomere dynamics—how chromosome caps shorten with each cell division and why this limits replicative lifespan. Oxidative stress is explored through the lens of reactive oxygen species and their damage to DNA, proteins, and lipids, alongside the role of antioxidant defenses. Cellular senescence is covered in detail, including the senescence-associated secretory phenotype and its contribution to tissue dysfunction. Mitochondrial function is analyzed from energy production to the role of mitochondrial DNA mutations and their impact on cellular energetics. Each topic includes an overview of key experimental evidence, such as studies on telomerase activation, caloric restriction, and senolytic drugs. The course also addresses the interplay among these mechanisms—for instance, how mitochondrial dysfunction amplifies oxidative stress, which in turn accelerates telomere attrition. The methodology emphasizes critical evaluation of longevity research. You will learn to identify common pitfalls, such as conflating correlation with causation in observational studies, misinterpreting effect sizes, and succumbing to survivorship bias. The course covers how to assess intervention claims—whether supplements, diets, or therapies—by examining study design, reproducibility, and mechanistic plausibility. You will practice applying these criteria to real-world examples, from resveratrol to intermittent fasting, learning to separate robust findings from preliminary or exaggerated reports. This course is designed for biology or health science undergraduates seeking a concise yet rigorous overview of aging biology; medical and nursing students who need to understand the molecular basis of age-related diseases; clinicians and healthcare professionals who counsel patients on aging interventions and wish to base advice on current evidence; and science communicators or writers who cover longevity topics and require accurate foundational knowledge. By the end, you will be able to describe the four key mechanisms of aging in precise scientific terms, explain how they interact to drive the aging process, and critically evaluate common longevity claims using evidence-based criteria. You will have a vocabulary that includes terms like telomere, senescence, oxidative stress, and mitophagy, and a framework for interpreting new research as it emerges. The course does not promise personal longevity changes but provides the tools to understand the biology behind the headlines.