It's a good thing that you're exercising. Your food intake will also have a huge impact on your results.
How fast you will go from a 36 to a 34 will depend on what you start with and the difference between your effective calorie intake and output.
Targeted fat reduction IS A MYTH:
Spot reduction is a myth that exercising and training a particular body part will preferentially shed the fat on that part. For example, doing sit-ups is not the best way to reduce subcutaneous abdominal obesity. One cannot reduce fat from one area of the body to the exclusion of others. Most of the energy derived from fat gets to the muscle through the bloodstream and reduces stored fat in the entire body, from the last place where fat was deposited. Sit-ups may improve the size and shape of abdominal muscles but will not specifically target belly fat for loss. Such exercise might help reduce overall body fat percentage and shrink the size of fat cells.
Eat healthy (go around the outside of the grocery store where all the non-processed, non-sugary stuff is).
If you just want to burn calories, these are the most effective and efficient ways of doing that (keep in mind that your food intake might increase with greater appetite):
Burn energy by running, crossfit, climbing or just being active.
Which Cardio Exercise Burn a Lot of Calories?
1. Step Aerobics
2. Bicycling - stationary or outdoors is a great cardio exercises, depending on resistance and speed.
3. Crossfit/P90X/Calisthenics and similar - works out your whole body and can burn a ton of energy in a very small time frame.
4. Racquetball - side to side sprinting makes racquetball and excellent cardio exercises. A 145-lb person burns over 400 calories in 30 minutes.
5. Rock Climbing - is not only a cardio exercises, but also uses arm and leg strength and power. Rock Climbing can burn up to 380 calories in 30 minutes.
6. Cross-Country Skiing - whether on a machine or outdoors on snow, is an incredible cardio exercises as it involves both upper and lower body. A 145 lb person can burn approx 330 calories in 30 minutes.
7. Running - Running is an excellent cardio exercises because all you need is a pair of quality running shoes. Running burns serious calories. A 145 LB person can easily burn 300 calories in 30 minutes.
8. Elliptical Trainer - is an excellent cardio exercises and a great way to build endurance. A 145 LB person can burn about 300 calories in 30 minutes.
9. Rowing - is both a cardio exercises as well as giving your arms an incredible workout. 145 LB person can burn about 300 calories in 30 minutes.
10. Walking - Brisk walking is a less strenuous form of cardio exercises. Walking can burn up to 180 calories in 30 minutes. Sprinting, adding hills or an incline can increase amount of calories burned.
For the real high intensity cardio people out there who love the H.I.I.T training (High Intensity Interval Training), below are the top three cardio exercise which will provide the biggest bang for your time invested:
1. Jumping Rope - This is one of the simplest, yet most effective exercises one can do. In just 15 to 20 minutes, jumping rope will give you an unparalleled total body workout. Jumping rope is ideal for cardiovascular endurance and enhances performance in virtually any sport - tennis, basketball, football, skiing, volleyball and more. This simple exercise is also great for eye-hand coordination, lateral movement, foot and hand speed and agility.
2. Sprinting - Sprinting not only burns HUGE amounts of calories while sprinting, it also keeps your metabolism flying for 24h after. Sprinting combined with running / jogging can bring amazing results
3. Spinning - These high-intensity workouts to music simulate a challenging bike ride, complete with hills, valleys and varying speeds, all dictated by the group instructor.