BLOG FITNESS, CADIO
August 23, 2013
What is Cardio and Why is it Important?
Lately I have addressed this issue with many folks who want to lose weight, but only want to lift weights. They hear things like, “weight training increases your metabolism, cardio keeps it low.” And, “weight training burns more calories in the long run, because I will have more muscle mass and will burn more calories at rest.” These statements are gross exaggerations of the facts. Any exercise will increase your metabolism. The more intense it is, the higher the increase in metabolic activity. More muscle mass leads to a higher resting metabolic rate, but it is a very low return on your effort. One pound of muscle burns about 6 calories per day. You would have to gain over 20 lbs of muscle to accommodate an extra PowerBar per day (mind you, more muscle mass burns a lot more calories while you exercise). You will get way more bang for your buck by eating well.
Typically, when most people weight train, they lift weights with lots of rest in between sets. They complete 3 sets of 12 reps and rest for 90 seconds between sets and exercises. This is very effective for building strength, but horrible if you want to burn calories and lose weight. When people think “cardio” they typically think of long and slow duration exercise while on a hamster wheel or treadmill or something of the sort. Let’s redefine this word to mean “any exercise activity that keeps your heart rate elevated with the intent of burning calories or getting / remaining fit and healthy.” That is a lengthy definition but is necessary because being stressed out will increase your heart rate but it is surely not with the intent of being healthy. Now that we have this new definition we can think of cardio as anything from jogging to circuit training, or jump-roping to boxing. Any activity you do to deliberately keep your heart rate elevated will count as cardio. Typically, strength training is not done with the intent of keeping the heart rate elevated. Strength training is very important but it utilizes different energy systems. We will talk more on this later. But first, let’s establish some ground rules on how to achieve your goals.
The first rule of achieving your health goals (no matter what they are): Eat healthy most of the time.
By most of the time, I mean 90% of the time. The 90/10 rule is a great rule to follow. 90% of the time, eat like your body is a sacred temple never to be desecrated by pizza or sludge filled foods. 10% of the time, eat like your body is a frat house on Saturday night. Throughout the week, following this rule allows you 3.5 “bad” meals per week. You should be getting in 5 feedings per day. Note that these are not ‘cheat’ meals or ‘reward’ meals. They are just not part of the 90%. If you make food a reward for anything, then we have more issues to talk about later. We all know that you cannot outrun a bad diet. Eating clean is the first part of achieving any health goal. If you do not eat well then you cannot complain about not achieving your goals. This may sound harsh, but this is a fact.
The second rule of achieving your health goals: Do physical work
Burn calories! Do work. Lift things. Move. Travel (trainers call this locomotion). Get your heart rate up. The body is meant to move. Period. The less you move, the slower you will get to your goal. The more you move, the faster you will get to your goal. Because we sit most of the day, when we exercise we need to cram in as much movement as possible. If we were out and about moving around most of the day, our exercise needs would be MUCH different.
The third rule: You cannot have healthy success without following BOTH rule one and two.
Also, you have to sleep, avoid chronic stress, drink water, be productive, have purpose, and all that other stuff. Each of those things affect your mood and associated hormones, and they have a huge long term impact on your health.
So let’s get down to the difference between traditional strength training and our new definition of cardio.
When you strength train, this is what happens:
You get to the weight room and you lift weights. When you pick up a weight, your body / brain says, “here we go… time to do work.” You start to shunt blood away from your guts and into the working muscles. Your central nervous system (CNS) activity increases and you also get an increase in sympathetic nervous system (SNS) activity. This means you have more adrenaline in your blood helping to pump your heart and control blood flow, as well as mobilize energy. Given the load you are lifting, your body needs energy now!.. so your muscles steal phosphate molecules off of creatine to replenish burned ATP (energy), and then starts splitting sugar in half to get more energy to make ATP, and then… oh wait, you are done. Time to rest before the next set. During your previous set, your heart rate may have gotten in the 150’s and now, during your next 90 seconds of rest, it will get back down to the 120’s or so. Ok, rest is over and time to lift again. Now your CNS and SNS are activated so we jump right into the utilization of creatine and sugar to fuel your muscles. Then we rest… rinse and repeat. After an hour of lifting, your average heart rate is about 135 and you have burned 300 calories. No… not 500 calories…. About 300.
Let’s look at Cardio.
You start to jog / run. Your body says, “here we go… time to do work.” You start to shunt blood away from your guts toward your muscles. Your CNS and SNS activity increase. You need energy now, so you start to use creatine and sugar to replenish ATP. And then….. you keep moving. No rest during this workout. Now that you are not resting, your body needs more energy so it keeps burning sugar in your muscles (by this time your creatine is all used up). After a couple minutes you feel like saying, “jeez, this sucks. I don’t remember cardio being this hard.” But that is just because your body is warming up. After 5-10 minutes, you feel this wave of relaxation, and you think, “ok, now I feel good. I could do this for a long time.” This is the point at which your body has been exercising long enough to mobilize fat from your fat stores and get it into the blood, through your muscles, and into your mitochondria to be burned. At this point, you are burning sugar in your muscles and mobilizing sugar from the liver to be used as well. Also, you are burning fats that have been stored in the muscles as well as mobilizing stored fats (like the ones around the belly) to be used during exercise. The harder you work, the more calories you will burn (both sugar and fat). The higher your heart rate the more work you are doing and the more calories you will burn. In traditional strength training, the load (weight) lifted is too heavy to be performed long enough to burn much fat and keep the heart rate up. Because of the load, you must rest. And resting does not burn calories. Anyways, once you are done with a cardio workout, you may have covered 7 miles, kept your heart rate at 155, and burned over 800 calories.
A trained body is very good at burning fat and sugar. When you exercise your body produces waste products called metabolites. They are broken down, excreted in the breath, buffered in the blood, or recycled in other tissues. The harder you work the more metabolites are produced and if you keep increasing the intensity you will reach a point where metabolite clearance is outpaced by production. What is the point?.. Well, some of these metabolites decrease pH within the muscles. The lower the pH the more your mitochondria are turned OFF. In a nutshell, lifting heavy weights decreases your ability to acutely burn fat (though it is great for burning sugar…. But so is cardio).
When it comes to fat burning, and getting lean, there is no better way than eating well and crushing your exercise. Mind you, there is a way around this in regards to strength training: lighten your weight up and don’t rest. Perform circuit training to keep your heart rate up and limit the rest. This is a great way to get the best of both worlds. Doing circuit training will not make you as strong as lifting heavy and it will not make you as aerobically conditioned as cardio, but it will keep your heart rate up, burn calories, and help get you lean.
But, you can totally fail at cardio. Long slow cardio will not do anything (other than take forever to reach your goal and practically waste your time). Unless you are an endurance athlete, stay away from long slow cardio. When you do cardio, you have to push yourself. If you are not getting your heart rate above 70% of your reserve, you might as well go take a nap. You did not come to the gym to get a massage, but to burn some dang calories. If you push yourself on your cardio you will burn more calories and more sugar. Forget about the lazy fat burning zone. Get into the workout zone and crush it. This will keep your metabolism going for longer throughout the day. We call this Post Exercise Oxygen Consumption, or EPOC. The more work you do in a workout, the higher the EPOC. If you walk all workout, that will lead to very few calories being burned, and therefore a VERY small deficit to recover from. So again, do more work.
So, in a nutshell, keep your heart rate up and do as much work as you can in the time of your workout. All of this workout recommendation business comes down to intensity. I am sure that later I will be arguing how you better keep strength training in your routine because it is a necessary component of fitness. But it is the intensity of your training that matters. Traditional strength training allows for more rest. Circuit training allows for very little rest. Running hard allows for zero rest.
Go do some work!
main image courtsey of www.womenshealthmag.com