To burn the optimal amount of body fat, you need cardio. (Sorry, cardio haters). But no one said it had to be boring. Choose any of the following five cardio options, doing it either when you go to the gym for your weight workout (just be sure to do cardio after wights) or at another time of day, such as first thing in the morning on an empty stomach. In weeks 1-3, do cardio 4-5 times a week; in weeks 4-5, do cardio 5-6 times a week.

1) Interval training A:
Equipment: Treadmill, elliptical, recumbent bike or rower.

Workout: Five minute warm-up; 25 minutes at a 1:1 high:low intensity ratio (for instance mine minute sprinting on a treadmill, followed by one minute at a jogging pace); five minute cool down.

2) Interval training B:
Equipment: Treadmill, elliptical or outdoor track.

Workout: Five minute warm-up; 25 minutes at a 1:2 high:low intensity ratio; five minute cool down.

3) Sprints
Location: Indoor or outdoor track.

Workout: Jog two laps as a warm-up; 4×400-meter sprints with two-minute walking recovery between each; jog two laps as a cool down.

4) Long, Steady Pace Cardio:
Equipment: Treadmill, elliptical, or recumbent bike.

Workout: Go at a challenging pace for 45-60 minutes; the pace should be difficult enough that you break a sweat, but you should still be able to pass the “talk test” (where you can speak without becoming breathless).

5) Hill Repeats
Location: Either on a treadmill with an incline feature or an outdoor hill (choose a steeper incline if you have a higher fitness level).

Workout: 10 minute jogging warm-up; perform 10 50-yard sprints up an incline with one minute walking recovery between each spring (or a brisk walk/jog back down the hill); 10-minute flat-terrain jogging cool down.

Burn 1,000 calories with a workout that’ll leave you gasping for air and begging for mercy.

What it is: A fat burning, muscle building workout that blends striking with interval training. You’ll punch with jabs, crosses, hooks, uppercuts, and perform front kicks and roundhouse kicks. Students are expected to be exhausted afterwards. The average guy will burn between 800 and 1,200 calories in a one hour class. And his metabolism will be 10% to 15% higher for the next eighteen hours.

Your first class: Wear loose fitting workout clothing and make sure you have the right sneakers. Since, you’ll be moving from side to side, cross trainers are the best. Also, bring a towel and a jump rope. You’ll warm up with a few minutes of light calisthenics, do some stretching and bodyweight exercises, then progress right into the kickboxing. You’ll switch from a high intensity exercise to a low intensity exercise, similar to sprinting.

Try this at home: Improve your jab. Start with your feet shoulder-width apart and knees slightly bent. Bring your weaker hand up near your ear, like you’re talking on an old telephone, and keep your other hand by your chin. Rotate your body slightly and bring that side’s leg straight back about 18 inches. Step forward and touch the floor with the ball of your foot as you finish the punch. The key is to push off the rear foot, because that’s where the power is. Throw a jab every second for 30 seconds and then take a 30 second break. Do six rounds of this. Inhale as you pull back and exhale as you punch. And make sure to keep your abs tight.

Super fast fitness come ons may sound more like infomercial speaking rather than science, but a study from McMaster University in Hamilton, Ontario, recently showed that short bursts of sprint training exercise can be as effective as longer workouts. When eight women in their 20s followed a 2 week long sprint interval training program of four to seven sets of cycling for 30 seconds at maximum effort, followed by 4 minutes of rest, three times a week, their endurance capacity doubled compared to those in a control group who exercised regularly. These short bursts of exercise are as effective as an hour of daily moderate activity, says study author Martin Gbiala, Ph.D. He says he isn’t sure why, but notes that muscle biopsies in the sprint group found increases in a muscles ability to use oxygen. We say run with it, literally. Interval training is ideal for busy people, such as business travelers, who often have a hard time squeezing workouts into jammed on the road schedules.

Heart disease grabs headlines, but back pain pesters 80 percent of American women. Exercise is your best defense, a recent Canadian study says. The key: Strengthen, then stretch. Mark Verstegen, author of Core Performance, offers these moves to help.

1) Strengthen: Plate Crunch

Increase Ab strength to help prevent lower back pain, but consult your doctor first. Lie on a Swiss ball, arching back. Hold a 3 to 5 pound plate behind head. Roll hips and chest up simultaneosly, pulling belly in. Crunch, then lower.

2) Stretch: Forearm to Instep Lunge

Step left leg forward in lunge. Place right hand on ground even with the left foot. Touch left elbow down to instep of left foot. Keep back knee up. Move left hand outside left foot and push hips up. Step right foot forward and repeat.

3) Stretch: Russian Twist

Lie with shoulder blades on Swiss ball and hips raised. Keep shoulders back. Extend arms above chest, holding hands together. Keep hips up and turn shoulders to right until perpendicular to fround with hips horizonta. Twist back to center, then to left.

University of California-Irvine researchers may have discovered one of the ways exercise slows brain changes found in the progression of Alzheimer’s disease! Mice that spent more time running wheels developed fewer plaque forming beta-amyloid protein fragments in their brains than sedentary mice. The scientists hope more research will show whether the same effect occurs in humans. New studies are already under way. The study also found that long-term exercise increased the rate of learning in the mice studied.