Cardio

When should you do your cardio?

From Scooby’s excellent fitness website:

There is a lot of confusion about when to do cardio, I get asked this question all the time! As many of you have heard, doing cardio before you eat in the morning burns off more calories so is that the best time? Lots believe that the right time to do cardio is before a weight workout to provide a warm up but just as many believe that the right time is afterward. Who is right? None of them! All of them!

The right time to do cardio is when you are most likely to do it! Cardio is very important and its 100x more important that you actually DO your cardio than when to do it! Lets look at some of the pros and cons of doing cardio at various times.

Doing Cardio And Weight Workouts Separately:

Its optimal to do your cardio and weight workouts completely separately, that is, with four or more hours of rest between them. This way, neither workout interferes with the other and you can give each 110% effort. For those of us who workout at home, this is easy to do. For those who go to gyms, its not as easy if you depend on the stationary equipment for your cardio because then you need to make a second trip to the gym. Now lets look at the non-optimal compromises.

Doing Cardio Before Breakfast:

Yes, studies have shown that you burn off more calories if you do cardio before breakfast, but its a lousy time to do cardio in my opinion because you wont do your cardio for nearly as long. Who can focus on cardio when your stomach is growling and you feel faint from lack of food? Not me! Besides, doing cardio before breakfast isn’t the most convenient time for most folks.

Doing Cardio Before A Weight Workout:

The fans of doing cardio before a weight workout point to its ability to help warm up your muscles to prevent injury, true it does this. For those who significantly overweight or are fitness beginners, walking or light jogging is the recommended cardio. For these people doing their walking or light jogging before their weight workout is perfect, it warms them up and doesn’t interfere with their weight workout. On the other hand, intermediate to advanced athletes need to push themselves much harder in their cardio workouts - they get their heartrate higher and keep it elevated for longer. Cardio workouts of this intensity will exhaust the body to the point where the weight workout will be lackluster at best reducing potential strength and mass gains. If you are an intermediate or advanced athlete whose time is at a premium and don’t feel its important to add more muscle mass then doing cardio before the weight workout is ok, otherwise find a better time to do cardio.

Doing Cardio After A Weight Workout:

Doing cardio after a weight workout is my personal favorite, its not optimal but its a very good use of time if you are doing your cardio at a gym because it eliminates the need for a second trip to the gym. I always find that even after an intense weight workout, I still can give cardio the intensity it needs. One thing I always do though is make sure to eat a small meal after lifting weights before starting the cardio. Meal timing is important and its important to get a meal right after weight lifting and waiting till after you do 45min of cardio, shower, and get home is too much of a delay. If you do your cardio after your weight workout, you need to find some alternative way to warm up your muscles before the weight workout, not a big deal.

Cardio and Fat Burning

For one, cardio and aerobic exercise are two names for the same thing - exercise that increases the need for oxygen (WordNet). Didn’t know that!

Our aim is to remove fat, not necessarily use energy. One may not involve the other. For example, we would prefer sucking out our body fat through surgery to jogging for 30 goddamn minutes everyday, if it were safe and cheap enough. But it isn’t yet, so we’re stuck with other means.

So, what causes us to burn fat? Well, we might naively think that we burn fat when we use energy in an activity. After all, that energy has to come from somewhere within our body. But, fat is not the only energy source we have. So, we have to do things that burn fat as much as possible.

All exercise makes us use energy. Aerobic exercises are those that make you get energy by converting carbohydrate into energy using oxygen. Anaerobic exercise (like weightlifting), on the other hand, are those that need so much energy that, in addition to aerobic metabolism, you convert carbohydrate into lactate, which causes the burn you feel afterwards.

Part of that energy used comes from the local energy stored in your muscles (called muscle glycogen) and part of it comes from burning fat.

Now, we want to burn as much fat as possible. That’s one of the main reasons we do cardio (apart from the health and cognitive benefits). When your heart rate is too high, you don’t get enough oxygen to convert carbohydrate the aerobic way, so anaerobic metabolism happens, which generates lactate and thus prevents you from doing this for very long. When your heart rate is too low, you get much of the energy you need from the local energy storage and not much from fat burning, which is not what we want.

So, the lesson is to do moderate intensity exercise for a long period so that you keep your metabolism aerobic and make your body burn the most fat. Apparently, you burn the most fat when your heart rate during exercise is consistently at 65% of its maximum. Don’t do low-intensity exercise for burning fat - it won’t work (from what I understand). Aim to elevate your heart rate to a reasonably high level for more than 20 minutes (h/t Scooby).

Question: Is using calories different from burning fat?

Is my understanding above correct? Is it that non-brisk walking uses energy from the muscles’ local storage but doesn’t burn fat too much (or at all)? So, is non-brisk walking pointless for burning fat? So, do those charts about calories used per hour in some activity not necessarily translate to fat burned?

Source: All of this was based on the Wikipedia article for aerobic exercise in January 2016.

Exercise Intensity

Exercise intensity refers to how much energy you expend when exercising.

Heart Rate is typically used as a measure of exercise intensity.

– Exercise Intensity on Wikipedia