How much cardio should I do?
How intense should it be?
Which machine is best?
Should I do it on an empty stomach or not?
These are questions I get all the time. Whenever I diet for a contest and start looking leaner, I get these questions a lot more (along with the usual ones about how I'm eating). I will answer the above questions not based on research studies, but from personal experience and from anecdotal evidence gleaned from many competitors in physique sports I have known and communicated with. Studies are great, but the problem I see these days is that many people become 'paralyzed' by too much information. Studies often contradict each other's findings, and some people are afraid to embark on any type of training or diet approach until they are certain it's the absolute best one. Sorry to say, but good luck with that. In the meantime, instead of following a routine or technique that may be 5-10% less effective than some other, they do nothing and get no results of any kind. Enough of that.
How much cardio should you do? Do as much as you need to achieve your goals. Wow, what a vague answer! It's intentionally vague because there is no magic formula to follow. There are general guidelines. The more fat you have to lose and the slower your metabolism, the more frequent and longer in duration your cardio will have to be. Another person who starts off leaner and has a faster metabolism may only have to do a fraction of the cardio that first theoretical person does.
What usually works is to start from a simple baseline of 30 minutes, three times a week. After about two weeks of that, you can add a fourth day, then a fifth day later on, and so on. Many people will continue to see fat loss at 4-5 sessions of cardio for 30-40 minutes a day. As long as you are still getting leaner, don't add more. There are some people who will need to do as much as 45-60 minutes of cardio, twice a day, to reach their fat-loss goals. Usually they allowed themselves to gain too much bodyfat, often in a misguided quest for more muscle mass. Obviously it's possible to overdo cardio, at which point muscle mass begins to be lost along with fat. The best way to avoid that situation is what I am always preaching - don't get too fat in the first place!
Now, what about the intensity level? The main debate in recent years has been about which is better: steady pace and longer duration, or higher intensity and shorter duration (HIIT style). It should go without saying that high-intensity cardio, like high-intensity weight training, should not be overly long in duration. But you want to know which is more effective? I've done both and still do, and I've known plenty of people who got into fantastic condition doing it both ways. This tells me that even if one is slightly better than the other, they both work. I will say this. If you don't have a lot of time for cardio, HIIT is definitely the way to go. I can burn the same amount of calories in 25 minutes that way as I can in 45 minutes of a steady, more moderate rate. But nonetheless, there does need to be a certain level of intensity involved for cardio to be effective. Shuffling along on a treadmill won't do jack, I'm sorry to say. Go to any gym, fitness center, or health club and you will see plenty of overweight people doing low-intensity cardio. Come back in a year, or two, and I bet you a 5-pound container of Myofusion Elite Peanut Butter Cookie Dough flavor they will still be overweight.
How intense should your cardio be? You can follow various heart rate formulas (Google heart rate for cardio) if you like, but I prefer the 'talk test.' If I can still talk to someone without huffing and puffing, I know I'm not working hard enough. If I can talk to someone at all during the sprint portions of HIIT cardio, I'm not really sprinting. I like to go by the calorie counts, even though I am aware they are probably not very accurate. At least they are consistent. I know that if I burn 500 calories in 35 minutes on an elliptical trainer at my gym today and 520 calories in 35 minutes tomorrow, I worked harder. When you get down to it, it's really a matter of preference which type of cardio you do, and no one said you have to choose one and stick to it. You can do steady-rate cardio on some days (such as when you do cardio after weight training), and HIIT cardio on other days, such as when you are only doing cardio that day.
The machine you use, or if you even use a machine, is also up to you. Swimming is out because your core temperature never rises high enough, and I don't like stationary bikes because your bodyweight is fully supported, so it's too easy. I alternate between the StepMill (toughest machine and most effective at fat burning in my view), the regular stepper, and running on an elliptical trainer. I find the elliptical trainer is best for the day after I train legs, as the StepMill works the legs much harder and they need to recover. On that note, I wouldn't even do cardio the day after legs normally. But when you're dieting for a contest and you need to display striated glutes, you do these things. The bottom line is that if you find a machine you like that gets your breathing and heart rate up and you're sweating rivers, that's a great machine for you whether I or anyone else says so. I mentioned that you may not even want to do your cardio indoors. If you prefer running stadium stairs or sprints at your local track, go for it.
Finally, what about the empty stomach debate? For many years, I have believed that cardio is most effective at burning fat when performed on an empty stomach. I did it myself, and I recommended it to others. I still feel it's very effective, but recent research is showing that it might not be as superior to cardio after eating as we have thought all these years. Another issue I have with doing cardio on an empty stomach is that there is a serious risk of losing muscle mass along with the fat. I feel this is of particular concern for athletes not training with the advantage of steroids to preserve lean muscle tissue. At the least, I feel you should have a BCAA drink like Aminolast or a whey protein shake rather than doing cardio on a truly empty stomach. This goes double if you are doing HIIT. A natural athlete doing HIIT on an empty stomach every morning is a recipe for muscle wasting as far as I'm concerned.
This hasn't been a fully comprehensive manifesto on cardio, but I did share most of my opinions on how it should be done. For those who are curious, currently I am doing 30 minutes on days when I do cardio after I weight train, and 35-40 on days like today when all I did was cardio. If it's HIIT style, I do a shorter session. At no point do I plan on doing more than 45 minutes a day, nor do I plan on double sessions. If it comes down to it near the very end when I still have trace amounts of stubborn fat on my glutes, I will do it. You do need to be flexible and willing to make adjustments as needed to your diet and your cardio, because there is simply no way to predict exactly how your body will respond as the weeks go by.
Special thanks to Pump reader Davoud Bayat in Iran, currently earning his Masters degree in exercise physiology, for today's topic.
Talk to you all later!