If you can’t seem to log the recommended daily 30 minutes in the gym, just clean your house. Believe it or not, standard chores like mopping, dusting and doing laundry can burn up to 250 calories an hour –- depending how hard you work.

According to celebrity trainer Grace Lazenby -- who has counted 'Desperate Housewives' star Marcia Cross as a student in her aerobics classes -- heavy housework rivals more official workouts in toning muscles and working your core. And it makes your house sparkling clean to boot. Experts caution that cleaning shouldn’t be your only activity, but you can modify your daily chores for maximum fat burning. Here’s how:

Use Your Core: Activities like mopping can burn as many calories as a brisk walk. If you contract your core muscles as you go, you’ll get an abdominal workout, too. "Try to breathe out as you push forward and in as you pull back with the mop or vacuum," advises Lazenby. And remember to switch arms so you work both sides of the body.

Banish Labor-Saving Tools: Chop veggies by hand rather than using a food processor. Use a real broom and dustpan instead of a broom vac. Wash and dry dishes by hand rather than dump them in the trusty dishwasher.

Create an Interval Workout: "Climb two flights of stairs or do 100 jumping jacks between each chore," suggests Lazenby. Do the dishes downstairs, then make beds upstairs. Go downstairs to dust and back upstairs to fold laundry. While it may take more effort, and more time, your thighs will thank you.

Work Out While You Wait: If you’re nuking food in the microwave, use the time to do some squats or push-ups against the counter. Waiting for the coffee to brew? Do some yoga stretches.