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How to burn 300 calories in 30 minutes 
Go for a jog. 
One great calorie burning exercise to try is jogging. It's a higher impact exercise that requires the use of many large muscle groups to perform.
To burn at least 300 calories in a half an hour, you have to jog or run. Aim for your pace to be around a 10-minute mile or 6 mph (if you're on the treadmill).