If you are trying to lose weight or keep the weight off, how many calories you burn during exercise matters. Your goal should be to burn 1500-2500 kcal (scientific way of expressing human energy used), per week. In this case, more is better!
With all the hype about Cross-Fit, TRX, circuit classes and the like, you might think that is your best route to burning lots of energy and thus losing weight.
If you can find out how much oxygen you consume per minute you will know energy used as one liter of O2 = 5 kcal. With a sophisticated measurement device (Oxycon Mobile) that was put to a test!
For a period of 30 minutes to get a good average, with a second session to validate the numbers, we used sessions of various activities and analyzed the data. The numbers below are for a 210-pound male, and your numbers will vary on fitness level, amount of muscle, and how familiar you are with the activity. The results are quite contrary to what you hear from personal trainers and read in the magazines!
Activity Kcal per hour
Weight Training/Upper body 300
Weight Training/Lower body 315
Circuit Weight Class 365
Hill Program, stationary bicycle 460
Spinning Class 775
Treadmill or Elliptical 900
The results indicate weight training is good at building muscular mass and strength, yet as an energy burning or weight loss activity is no where near as good as cardiovascular activities performed at a moderate pace. Weight training is not continuous, and cardiovascular training is continuous, so that is the main reason for the big differences in energy used. The bottom line is do only enough weight training to maintain your muscular mass and strength, normally 1-2 sessions per week for most people. Cardiovascular training for 3-4 sessions a week will yield greater benefits for weight loss and weight maintenance!