# Longevity & Aging Domain Description Longevity and aging represents the intersection of preventive health and regenerative medicine, focusing on extending both healthspan (years lived in good health) and lifespan through evidence-based interventions. This domain matters because aging is the primary risk factor for most chronic diseases including cardiovascular disease, cancer, neurodegeneration, and metabolic dysfunction. Rather than treating diseases in isolation, the longevity field takes a systems-level approach to slow biological aging processes and maintain cellular function across the lifespan. Research in this space examines mechanisms of aging including mitochondrial dysfunction, cellular senescence, telomere shortening, oxidative stress, inflammation, and loss of proteostasis. Understanding and modulating these processes through supplements and lifestyle interventions represents a paradigm shift from reactive disease treatment to proactive health optimization. Supplementation in the longevity domain shows varying levels of evidence across different compounds. NAC (N-Acetyl Cysteine) has demonstrated potential in supporting glutathione synthesis and reducing oxidative stress, with observational evidence suggesting benefits in aging-related conditions, though large randomized controlled trials in healthy aging populations remain limited. NMN (Nicotinamide Mononucleotide) and related NAD+ precursors have shown compelling mechanistic evidence in animal models for supporting mitochondrial function and sirtuins, though human evidence is still emerging with smaller studies showing mixed but promising results. CoQ10 has established evidence supporting mitochondrial energy production and has been studied in cardiovascular health and aging populations. Taurine shows interesting mechanistic data suggesting roles in mitochondrial function, muscle maintenance, and cellular stress resistance, though human longevity studies are limited. Selenium functions as a critical cofactor for selenoproteins including glutathione peroxidase, with evidence supporting antioxidant and immune function, though evidence for lifespan extension in humans remains indirect. Quercetin and Resveratrol are polyphenols with strong in vitro evidence for senolytic and anti-inflammatory properties, though human studies typically show more modest effects. Spermidine has shown promising mechanistic evidence in autophagy and longevity pathways in model organisms, with emerging human data. Glutathione serves as the body's master antioxidant, though evidence for supplementation effectiveness is mixed due to bioavailability challenges. Evidence tiers vary significantly across these compounds, from stronger evidence for established nutrients like CoQ10 and Selenium to emerging evidence for compounds like NMN and Spermidine. Lifestyle interventions represent perhaps the most robust evidence base in longevity science. Zone 2 cardio, characterized as aerobic exercise performed at 60-70% of maximum heart rate, has strong evidence for supporting cardiovascular health, mitochondrial biogenesis, and metabolic flexibility while minimizing injury risk compared to high-intensity training. Resistance training consistently demonstrates benefits for preserving muscle mass and bone density with aging, maintaining metabolic health, and supporting longevity outcomes in epidemiological studies. Sauna and heat exposure has emerging evidence suggesting hormetic stress responses that may upregulate heat shock proteins and provide cardiovascular benefits, though the optimal frequency and duration remain subjects of investigation. Intermittent fasting shows mechanistic promise for autophagy and metabolic health, with human evidence suggesting benefits for metabolic markers, though individual responses vary considerably and adherence remains a significant factor. Social connection and meaningful relationships demonstrate some of the strongest epidemiological evidence in longevity research, with studies showing that social isolation carries health risks comparable to smoking and obesity. These lifestyle factors often work synergistically, with combined implementation showing greater effects than isolated intervent