By Nicole Dorsey
A three-hour Spinning class that simulates climbing Mount Everest? Might be a bit much for us mere mortals, but if you are looking for a real challenge, we've found four tough-as-nails classes that'll give you the sky-high calorie burn you crave. Even if they're too over-the-top for you, just reading about them might inspire you to kick up your own workout a notch or five. (If you don't happen to live near a gym that offers any of these classes, we've found DVDs that promise a similar challenge.) Don't say we didn't warn you!
Related: How to Burn More Calories in Less Time
Try It At: Crunch Fitness Clubs, New York City
The Benefit: Adding weights to traditional yoga moves gives your muscles more of a challenge.
Calories Burned: 400 to 500
Fitness instructor Suzi Teitelman teaches a flowing 60-minute yoga class using concave, plate-shaped, 6-pound weights called Smart Bells that challenge your balance while toning your muscles. She adds weights to all poses, including sun salutations, tree pose, and even pigeon pose. The additional resistance boosts the sculpting benefits of any pose, she says.
Signature Move: Weighted Boat Pose
Sitting on the floor with knees bent, lean back 45 degrees to engage abdominals. Lift shins parallel to floor and balance Smart Bells (or light dumbbell) across the tops of both lower legs, arms extended. Sit up tall and extend both arms toward toes, breathing deeply for 30 to 60 seconds.
At Home: Try Smart Bells Fusion DVD, $19.95 (or $74.95 with a 3-pound Fusion Smart Bell) at smartbells.com.
Related: Extreme Yoga Poses and Positions
The Mount Everest Ride
Try It At: Cornerstone Health & Fitness, Doylestown, Pennsylvania
The Benefit: Burn more than a day's worth of calories in just three hours.
Calories Burned: 2,000 plus!
Professional cyclist (and Spinning master instructor) Josh Taylor teaches this three-hour Spinning class that simulates a climb up Mount Everest -- complete with a spectacular slide show. You'll visualize pedaling up sheer vertical terrain to the base camp, then continuing to camps one through four. "When we get to 'camp,' we rest, pedaling with no resistance for 5 to 10 minutes," says Taylor. During this inspiring marathon, cyclists simulate steep climbs, frequently riding out of the saddle. Taylor plays Tibetan chants to set the mood while shouting out encouragement.
Signature Move: Climbing the Peak
Once the class reaches the "crest," Taylor asks students to close their eyes and ride at their hardest resistance for 10 minutes out of the saddle. Half the class sobs or shouts hysterically when they reach the "top" and Taylor tells them to visualize placing their stake at the peak of Mount Everest.
At Home: Try Spinning Spin & Burn DVD, $24.95 at spinning.com.Warrior Workout
Try It At: Pow! Krav Maga Martial Arts and Fitness Training Center, Chicago
The Benefit: You'll supersculpt your lower body and learn to fight like a pro.
Calories Burned: 400 to 600
Instructor Katalin Rodriguez-Ogren warms up the class with six to eight minutes of jump rope mixed with leg lifts, half squats, and skipping with knees high. Next comes a series of knee strikes, kicks, and jab combos, and then they hit the heavy bag. Afterward, students run up and down seven flights of stairs.
Signature Move: Roundhouse Drill
Stand with feet hip-distance apart and fists protecting your face. First, perform roundhouse kicks continuously for 30 seconds with your right leg, kicking in an arc from right to left, keeping knee bent between each kick. Next, hold your right knee to hip height and pulse leg up and down for 30 seconds. Then kick with an extended leg for 30 seconds. Finish by holding the extended right leg out to the side and pulsing for 30 seconds. Switch legs and repeat.
At Home: Try G.I. Jabb Warrior Workout DVD, $29.95 at exercisedvds.com.
Related: The Metabolism-Boosting Superset Workout
Plyometric Athletic Circuit
Try It At: Easton Gym, Santa Monica, California
The Benefit: By the time you catch your breath, you'll burn off the calories in more than half a pint of Haagen-Dazs chocolate ice cream -- and sculpt sexy muscles.
Calories Burned: 600 to 700
Every Saturday morning at 7:45, 20 gung-ho exercisers warm up on stationary bikes and treadmills. They're getting ready for an all-out cardio kick-butt workout led by former Olympic swimmer and strength coach Tom Williams. Eight 90-second cardio stations call for plyometric hops over a step, alternating with strength exercises that use resistance. Each 90-second cardio interval ends with full-on sprints. After 60 minutes of cardio-sculpt stations, Williams sends the staggering class back to the treadmills and stationary bikes for another 20 minutes of aerobic work.
Signature Move: Squat Jump
Stand with legs shoulder-width apart, straddling a step. Bend knees into a 90-degree squat. Hold for 30 seconds. Jump up onto the step, then jump back into the squat. Do 12 reps. Finish by holding a 90-degree squat for 30 seconds. Rest for 15 seconds, then complete 3 more sets.
At Home: Try Cathe Friedrich's Imax 3 DVD, $26.95 at collagevideo.com.
Related: How Fit Are You Really? A Test to Find Out
More from FITNESS Magazine: