An overdraft occurs when money is withdrawn from a bank account and the available balance goes below zero. In this situation the account is said to be overdrawn. If there is a prior agreement with the account provider for an overdraft, and the amount overdrawn is within the authorized overdraft limit, then interest is normally charged at the agreed rate. If the negative balance exceeds the agreed terms, then additional fees may be charged and higher interest rates may apply.
Ditch the riding mower for a traditional push mower for a cardio workout that conditions the calf muscles. According to CalorieCount.com, a 150-pound man can burn 408 calories an hour mowing the lawn. Trim the hedges Gas-powered hedge trimmers are for cheaters. Do it like a man and grab a pair of manual cutters.
But to answer your question, yes cardio can burn up your muscle if done improperly. If you do nothing but stay on the stair master for an hour every day then you will likely burn up muscle along with some fat. The best way to burn fat is with weight training. The more muscle you add the easier it is to stay lean.