You lose muscle mass as you get older, Blue. Generally we were more active as youths, walking bicycling everywhere. We had more time for sports, exercise, etc. If we worked, we weren't (usually) stuck at a computer. So we lose muscle mass. Loss estimates I've read are around 5 lbs per decade. That's quite a bit of metabolic tissue to be losing (muscle burns calories even when you are at rest). You can gain it back, tho, w/regular strength training. Ask the kines trainer about this, they should be able to explain this to you.

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