Did you know that after the age of 35, the average person loses between 0.5% and 1% of their muscle mass annually, which translates to a loss of approximately 5% to 10% of muscle mass every decade!?
Some sources indicate a rate of 1% to 2% per year, meaning a loss of 10% to 20%.
The only way of stopping this is... tarara STRENGTH TRAINING! :)