Several normal aging changes explain what we experience as we age, most notably: cross-linking of elastin and collagen that make tissues less elastic, and apoptosis or programmed cell death that leads to fewer available cells.

I discuss ways to mitigate those changes to provide optimal quality of life. For example: fewer muscle cells requires remaining cells to produce more protein each to provide the same strength, and requires us to exercise more frequently to maintain strength and condition as atrophy of the protein is faster.