For the purposes of this, will split cardio into two types:
High intensity and low intensity
High intensity is typically in the form of HIIT, High Intensity Interval Training. This is where you sprint for a short period of time, then go at a light recovery pace for double the sprint time, then repeat. Aerobic workouts like TaeBo etc. also qualify as this type of cardio.
Low intensity is picking a single pace and maintaining it for the duration of the workout.
Intensity is measured by your heart rate, not by speed.
There is always debate about what type to use and when. Here is my take on it…
HIIT does to your body pretty much exactly what weight training does. It requires almost entirely carbs in terms of energy source, and it boost GH production like a weight training session. Another benefit of HIIT, the biggest benefit, is it’s effect on your cardiovascular system. It increases endurance, lung efficiency, lowers LDL cholesterol, raises HDL cholesterol, lowers blood pressure, and lowers resting heart rate. Fantastic for overall health.
The negative of HIIT is that it unless you treat it like weight training, it WILL burn muscle. It causes production of cortisol just like weight training does and taxes your nervous system just like weight training, especially if the intensity is very high.
Low intensity cardio will only have a slight effect on your cardiovascular system and won’t do much of anything for endurance except in people who are very out of shape. The benefit of low intensity cardio is that it almost exclusively burns fat. So low intensity cardio is obviously important for keeping those luv handles at bay. Because it burns fat almost exclusively, unless you are in a horrible caloric deficit, low intensity cardio is highly unlikely to cut into muscle gains.
So when and how should you use these types of cardio? Many may disagree, but my recommendation is, when cutting almost all your cardio should be low intensity. Your goal is fat loss so best to use your time most efficiently for it. HIIT requires extra calories to prevent catabolism, and that’s not something you want.
When bulking, you should make an effort to do HIIT once or twice a week. However, those session should be on their own, and treated just as a weight training session. That means you take in a carb meal 3 hours beforehand, a carb meal 30 minutes to an hour beforehand, and you have a lot of protein afterwards. The benefit while bulking, if you treat HIIT this way will be enhanced muscle gain, far less fat gain (and if your diet is in order possible fat loss), increased endurance (allows for better workouts), and most important during a bulk that so few ignore is it keeps your heart healthy while you gain weight. Many ignore the health problems associated with gaining weight rapidly during a bulk. Even if you gain almost exclusively muscle, if you bulk quickly it takes a toll on your body. Your blood pressure is the most easily effected.
Look at all the guys who get so out of shape in the off-season. They have trouble walking up stairs. They huff and puff after every set and have to take several minutes rest between sets and between exercises. Their workouts take forever for a relatively small number of sets. Sure they’ve got strength but they don’t have any endurance and it DOES negatively effect their workouts.
If they were to add HIIT training sessions and eat appropriately for those sessions, they could take 60-90 seconds between sets and have all their strength regained. They’d find they recover faster between workouts and may even find themselves able to add an extra workout a week. On top of that, they won’t gain so much fat to go along with the muscle they are gaining. The best of all is when it comes time to cut, their endurance will be so high, they can do low intensity cardio at a pretty fast pace, which means they can burn more calories exclusively from fat when it comes time to their cut than most folks can simply because their hearts are so efficient.
You can also do low intensity cardio during a bulk, but save this for first thing in the morning, keep it extremely low intensity, and only for 30 minutes. Don’t do it every day, only a few days a week at most. When done this way, it will only burn fat, and will actually increase your appetite and prime you for absorbing the nutrients in your breakfast.
When I don’t agree with doing cardio:
After a weight training session. You have a window of opportunity after lifting that should never be wasted. Your body is highly insulin sensitive at that point, and your growth hormone levels have likely peaked. You want to EAT. There are also a number of supplements which are beneficial at this time that should be taken as soon after a workout as possible, and along with food. GXR is a good example, so is creatine. If you delay that by tacking cardio on the end, you begin to lose that window of opportunity. On top of that, by extending your workout longer you start to crank out too much cortisol and it can and will cut into muscle gains. During a cut this is even worse since you are already in a caloric deficit; it will actually start to burn your muscle.
Anyway, that’s my take on cardio. Take it for what you will.
