Some 60 million Americans are members of gyms or health clubs, but each year, thousands complain about contracts that cost more than they expected.

The Better Business Bureau receives more than 6,000 complaints each year about health clubs, fitness centers and gyms.

Consumer attorney Andrew Wolf's pet peeve is when gyms make it hard to cancel. "My view is, if you sign a one-year membership, it should end at one year," he says. "These contracts should stop and there should be some... affirmative authority to say I want to continue this."

For people who live in New York, gym memberships can only run one year and cannot contain an automatic renewal. New Jersey health club contracts can run up to three years -- and the law says nothing about auto-renewals. And while Connecticut says "no health club contract can contain an automatic renewal," it goes on to say that they really can -- for a month at a time, which could mean paying a second month to cancel.

So what can consumers do to protect themselves? Wherever you live, make sure you read your contract carefully. Check for hidden fees, like annual enrollment, or rate-lock charges. Check if you can cancel early -- and how much that will cost. And beware of low-cost lifetime memberships, as they can mean that a club is in financial trouble.

Before you join a gym, it's a good idea to check for complaints with the BBB and with your state's department of consumer affairs.