A 51-year-old personal trainer shares his 20-minute workout to build an maintain muscle

Harley Pasternak, a 51-year-old celebrity personal trainer, shares a 20-minute daily workout routine six days a week to build and maintain muscle mass. The routine focuses on two major body parts and the core, using varied exercises to prevent boredom and promote muscle adaptation. Pasternak prioritizes recovery by avoiding overtraining the same muscles consecutively and incorporates 12,000 daily steps for heart and mental health.