Articles by David S. Klein, MD

Your resting heart rate is more than just a number—it is a powerful biomarker of cardiovascular fitness, autonomic nervous system balance, metabolic health, and healthy aging. Learn why "normal" may not always mean "optimal," what research reveals about heart rate and longevity, and how exercise, sleep, nutrition, stress management, and overall health influence your pulse. Discover practical strategies to improve cardiovascular efficiency and support a longer, healthier life.

Could C15:0 (pentadecanoic acid) become the first newly recognized essential fatty acid in nearly a century? Emerging research suggests this naturally occurring odd-chain saturated fatty acid may support healthy cell membranes, mitochondrial function, metabolic health, and healthy aging. Learn what current science tells us about food sources, supplements, recommended intake, and why researchers are paying close attention to this unique nutrient.