When it comes to using cardio to burn fat and lose weight, there are 2 schools of thought…
In one camp we have the long, slow, distance approach or LSD for short. LSD is all about selecting an exercise and performing it for extended periods of time at a comfortable pace. Heart rate is kept around 60% of maximum so you are slightly out of breath but comfortable for the duration of your workout. You can chat to anyone nearby should you so choose and almost all of the energy you are using is coming from fat being burnt. LSD is almost 100% aerobic (meaning with oxygen) and very little lactic acid will be produced in your muscles so it’s quite comfortable to perform. On the downside, although fat is the main source of energy in LSD type exercise, you won’t be burning much of it as our body’s are very efficient at making fat go a long way.
In the other camp we have interval training which describes periods of high-intensity exercise alternated with periods of rest e.g. sprinting for 60 seconds, walking for 120 seconds, repeated 5 times. Interval training is more anaerobic (without oxygen) than LSD and generally tougher to do as there is lots of lactic acid produced which can be uncomfortable. However, the production of lactic acid produces an effect called EPOC (Excessive Post exercise Oxygen Consumption) which means that after the workout has finished the body uses oxygen at an elevated rate to clear out the lactic acid in your blood. This means more calories are burnt even though your workouts will be shorter when compared to LSD.
Which is better for fat burning?
Interval training wins hands down for economy of training time but LSD training is certainly less demanding. The answer is probably to do a mixture of the 2 and get the best of both worlds!