Which is better to burn fat do an hour of running or 5 minute sprints every hour.?

I think your talking about High Intensity Interval training (HIIT). First, your body needs to prepare for this type of training regime. It's not something you can just jump into doing - without risking injury. It's specialized for individual athletic requirements. It's not an "anyone can do it" exercise, nor should it be used soley for weight reduction.

Fact is, a 2 minute all-out sprint burns the same number of calories as a 60 minute sustained jog. Sounds great right? There's a catch. Sprinting ALL OUT for 2 minutes is something Olympic track stars can do. 2 FULL minutes is a LONG time for the rest of us! Even those of us that are in good shape. The good news is, you can break this down into 30 second intervals, while doing sustained job with simular results.

Such as, jog for 10 minutes, sprint 30 seconds... repeat 3 times, and your workout lasted a little over 30 minutes, but your calories burned is the same as working over an hour.

Your calorie burn is based on your "targeted heart rate", which measures an individuals intensity level. When your working within your zone, up to 85% of your energy is coming from stored body fat. But you need to provide a sustained period of work (20+ minutes) before this constant is met. This is to allow your body to deplete it's glycogen stores before looking for alternative sources of energy. That's why a sustained jog + a 30 second interval works best.

HIIT is an anaerobic workout, so metabolism increases last longer (5-7 hours). Cardio workouts are Aerobic, with metabolism slowing after an hour or so.

To reduce 5 lbs, your wife would do better just to cut back on starches, processed foods, and sugars for a while. The results are longer lasting is she maintains an active lifestyle.

You should keep to the low intensity cardio for 60 minutes, this is because when you sprint you are using different energy stores. You burn carbs rather than fat when you sprint. When you do low intensity exercise you burn more fat rather than carbs. If i were you just stick to the 60 minute cardio, you can keep your metabolism going by eating healthy meals every 2-3 hours, roughly 6 meals a day. Hope i helped :)

consistent cardio is the best thing. Sprinting is a great way to develop your fast-twitch muscles and improve speed, but it's that constant, tedious jogging that will burn the most energy.

The interval setting on the treadmill should suffice. Make sure they're intense though.