Experts say we lose muscle mass starting at the age of 30 at the rate of about 10% per decade until we reach the age of 50, at which point the rate accelerates to 15% per decade, according to research conducted in Germany.

Original source: https://www.newsmax.com/health/anti-aging/strength-training-aging-workout-gym-jack-lalanne/2020/03/10/id/957673