This is the age old question so many people who exercise have wondered. When your at the gym, it’s nice to be able to knock everything out in one day. By doing your 60 minutes of weight training and 40 minutes of cardio, you are able to squeeze in more exercise, and maximize your efforts. Repeat this 3-4 times a week and you are really on the track towards success. However, many people have their theories on this. Theories are often times based upon this month’s issue of men’s health or some simple bro science from the meatheads in the corner ; two useless forms of fitness advice.
Let us intervene and shine some light on the subject. Never again will you have to play guessing games as to which way you should be working out.
When you work out, whether it is weight lifting or cardio, your body burns fuel. The preferred fuel of the human body is carbohydrates (glucose). The average body has roughly 400 grams of carbohydrate stores ready for use as fuel. When these stores begin to dry up, the body turns to burning fat as fuel. This is an important point to remember as it will help us make our decision about the sequence of our workout later on.
Jumping on the treadmill and doing 40 minutes of jogging may burn up to 600 calories. The components making up the 600 calories may be part fat, part glucose, and part blood glucose. A rough estimate would say you have used one quarter of your glucose stores. If you are like some people and have a sports drink or power bar while you work out, you will replenish these stores and be only slightly less depleted than you were when you walked in.
Lifting weights, particularly as heavy as you can handle, is terrific for sapping your body of its energy stores. Muscles love using glucose for energy. When you perform those heavy lifts, your body goes into overdrive to support the muscular system. A solid hour of moderate to high intensity training while almost completely deplete your body of its preferred energy sources.
What does this mean? Well, when your body has no more glucose to fuel movement, it must turn to fat to keep the engine running. By completely depleting yourself of energy stores in the first hour of weight lifting, your body turns to burning fat when you begin cardio. Cardio later in a workout will burn almost exclusively fat cells. For those that are interested in weight reduction and fat loss, this is a very good thing.
Forget what you have been told about “fat burning zones”. While more fat is burned at a lower intensity, more calories (and fat calories) and burned when you exercise at a higher intensity. Look at it like this:
At a low intensity (jogging) you burn 60% fat/40% glucose. At a high intensity (sprints) you burn 30% fat/70% glucose.
- Jogging for 30 minutes – 180 calories burned – 108 calories of fat burned
- Interval sprinting for 30 minutes – 500 calories burned – 150 calories of fat burned
While you can see that the ratio of fat calories burned is higher in the low intensity cardio, for practicality purposes, more fat is burned by doing high intensity cardio.
Focus on doing your lifting right when you get to the gym. Go hard with your lifts, then focus on doing cardio 100% for 40 minutes afterwards. This will allow your body to immediately jump into fat burning mode. The one exception to this is if you are lifting legs on any given day. You should try to split up your cardio and leg lift days for the simple fact that you will over train and get less benefit from the workout.
Hopefully this helps you stop playing the guessing game about which comes first, cardio or weight training. The goal for all overweight individuals is to burn fat. The best way to do so is to deplete energy sources and make your body run off of fat cells.