Without exercise, approximate muscle mass decline between ages 30 and 70 for women and men?

• A. 10% for women and 12% for men
• B. 22% for women and 23% for men
• C. 40% for both
• D. 50% for both

Answer: (B)

Muscle mass declines with age due to sarcopenia, and not exercising speeds up this loss. The typical decline after age 30 is about 3–5% per decade. Over four decades—from 30 to 70—that accumulates to roughly 12–20%. The closest estimate in the options is about 22–23% for women and men, which fits within that range and reflects similar proportional losses between the sexes when exercise is lacking. The other options suggest too little or too much decline over the same period: 10–12% is too conservative, while 40% or 50% would imply a far greater decrease than is commonly observed without intervention.