What Form of Cardio Is Best?
You’ve all probably heard something about the “right” way to do cardio, when to do it, how much, at what intensity, pre-workout, post-workout, fasted…the list goes on. But the truth is, cardio is subjective, in a way. People choose their “right” way of doing cardio typically based on what their goal is. For example, bodybuilders will typically do cardio post-workout because it gives them the opportunity to use their stored muscle glycogen for lifting weights, rather than burning calories while doing cardio. If bodybuilders were to do their cardio pre-workout, they would be using their stored muscle glycogen to run, use the elliptical, etc. and as a result, they wouldn’t have as much energy to complete their workout. So for bodybuilders, cardio post-workout is the right way to do cardio.
For others, cardio pre-workout may be more beneficial. Doing cardio prior to lifting weights puts your body in “fat burning mode” faster than would weightlifting. This means that by doing cardio first, you’ve revved up your metabolism so you’re burning calories at a faster rate, which means that you will also be burning calories at a faster rate during your workout. For those whose main goal is to lose weight, this may be the right way to do cardio. It depends on you and your goal. But what about HIIT (high-intensity interval training)? Or this whole phenomenon on lifting weights faster for cardio? You’ve heard about these too, right? Again, depends on your preference.
I’m sure by now you’ve seen many memes that include that conversation “ ‘What do you do for exercise?’ ‘I lift weights.’ ‘What do you do for cardio?’ ‘I lift weights faster.’ “ As silly as this claim sounds, it’s true. Lifting weights faster (I assume this means less rest in between sets) would, in fact, burn more calories than would lifting weights with longer rest periods. How much more calories? It’s probably a negligible amount, but the statement is true nonetheless. In any event, in order to induce muscle hypertrophy, you want small rest periods anyway (30s-90s max). Any length of time greater than 90's begins to induce strength gain (i.e. powerlifting), thereby, reducing the chances of muscular size increase (but that’s another topic for discussion).
So what is HIIT? High-intensity interval training is a form of cardio that has many purposes. Any exercise performed at 85% of maximum capacity and above is classified as high intensity. High-intensity exercise means that your body is burning carbohydrate for fuel. If you’re trying to lose weight, this is what you want. You can burn a significant amount of calories in a short period of time while doing high-intensity exercise. If you’re doing it correctly, you probably won’t be able to go longer than 20 minutes or so whilst performing HI exercise, which is fine…that’s all you need.
Where does high-intensity INTERVAL training come into play then? Well, HIIT is a form of HI exercise, which, if done correctly, can only be performed for about 10 minutes. Many cross fitters engage in HIIT in their training, which is why they’re typically so shredded. HIIT exercise consists of doing something (let’s use running as an example) for some period of time, and breaking for the same amount of time. If you’ve decided to implement HIIT into your training protocol, kudos to you! It’s not easy. Anyway, you would sprint (at full capacity) for say… 30 seconds. For the next 30 seconds, you would break. Not slow down, completely stop. Then you would repeat this pattern for 6 minutes or so before taking a real break. HIIT not only burns a significant amount of calories in a very short period of time, but it is also proven to increase VO2max, which is your body’s maximal ability to intake oxygen. The more oxygen you’re able to consume, the more efficient you are, the easier exercise will be. So have you been doing HIIT all wrong? You may think you’ve been doing HIIT, but you actually may have been doing another variation of high-intensity exercise, Fartlek training.
Like HIIT, Fartlek training utilizes your body’s maximum (or near max) ability to perform work. Fartlek training is done at a lower intensity than HIIT, which means that it can be done for longer periods of time. It is also easier because you are not performing your exercise at your maximum capacity. I typically do Fartlek training because it gives me an opportunity to do cardio for a relatively short period of time, burn an abundance of calories, and build some muscle whilst doing my cardio. My Fartlek regimen looks a little something like this (on the treadmill): 2 minute warm up (comfortable walking pace), 2 minute jog, 30 second sprint, 30 second jog, 30 second walk, 1 minute incline walk, 1 minute slow incline lunges, 30 second incline walk, 30 second no incline walk, 2 minute jog, 30 second sprint, 30 second jog, 1 minute walk, 30 second lateral walking squat (right side), 20 second walk, 30 second lateral walking squat (left side), 1 minute walk, 2 minute jog, 30 second sprint, 30 second jog, 1 minute walk 30 second pop squats (off treadmill), 2 minute walk. All of that totals a little over 20 minutes and it’s a killer workout. If you’re going to do this kind of cardio, I would advise doing it prior to lifting, or on a light lifting/off day from lifting otherwise, you won’t be able to do it at the end of your workout, due to lack of energy.
And on the other side of the spectrum, we have low-intensity exercise, which based on science says that it should be the most beneficial in burning fat because when we are working at low intensities (~ <60% of max) we are burning fat for fuel, not carbs or protein. So, one would think that cardio at lower levels is more beneficial for getting lean. Well, theoretically it is, but exercise at intensities of this level requires long, non-stop bouts of cardio for weight loss. Doing cardio at <60% of your max requires continuous exercise for 45 minutes (at a minimum). Is that something you want to do every day? Again, this cardio thing just depends on personal preference.
As you may have concluded by now, moderate intensity cardio (~ 60-85% of max) requires exercise somewhere in between high intensity and low intensity. ~35 minutes or so will do. If your body is burning calories in the “moderate” zone, it is transitioning from burning fat for fuel to burning carbs for fuel. Remember, while the goal is to get rid of fat, being in “fat burning mode” isn’t necessarily a good thing unless it’s for longer periods of time. A person who is overweight has an abundance of carbohydrate stored up in his tissues, which means that burning carbohydrate for fuel would ultimately benefit him more by riding his body of the extra carb storage. But again, what’s your goal?
Lastly, let’s talk about fasted cardio briefly. There’s this stigma about fasted cardio being bad for your body because you’re technically in starvation mode when you’re doing fasted cardio. And like just about everything else ever been researched, you can find data for and against this common assumption. Whatever the case may be, fasted cardio is beneficial for fat loss. Why? Well, when you go to sleep, your body is fasting all night. You aren’t eating and you are burning calories as you sleep, so when you wake up you are running mostly off of stored glycogen. When you do cardio on an empty stomach, your body uses this stored glycogen for fuel. But be careful, too much fasted cardio at one time can lead to protein metabolism, which we don’t want. We are only interested in carbohydrate and fat metabolism for fat loss. Fasted cardio is great for fat loss because you are able to burn stored glycogen for fuel, riding your body of its way to increase fat storage; thus, increasing fat loss. Treat fasted cardio like high intensity or moderate intensity exercise, do it for relatively short periods of time to put your body in a caloric deficit but not so much so that you’re taking away from your muscle growth.
So what’s your preference? Do you like cardio? Or do you just want it to be over? Do you get bored easily? Or can you handle long periods of monotony? Cardio at all intensities is beneficial for fat loss, however, it all greatly depends on how long you’re performing said cardio and whether or not you’re doing it pre- or post-workout. Don’t go into your workout blind. Know what your goal is and try to determine the best possible way to accomplish it.