Enhancing healthspan, by contrast, boils down to avoiding (or at a minimum delaying as long as possible) three categories of decline:

Cognitive decline—decline in executive function, processing speed, and memory; Alzheimer’s disease is an extreme version of this decline, but many far less severe forms of this decline are pervasive.
Physical decline—decline in stability, flexibility, mobility, strength, muscle mass, bone density, aerobic function, anaerobic function, functional movement, freedom from pain, and sexual function.

Emotional decline—decline in mindfulness, social support, sense of purpose, fulfillment, and relationality.

Peter Attia Longevity Framework