Cardio and Resistance

Body Fat
Body fat has certain rules which, from the beginning of time until today, have not changed.

1) Body fat is only burned through enzymes stored in the DNA of the mitochondria (the “power house”) of the cell.

2) Body fat, therefore, is only burned through aerobic or cardiovascular exercise. If you’ve heard that we burn fat as we sleep, this is true. We burn only small amounts but sleep is actually an “aerobic” activity.

3) “Burning body fat” is a bit different than the image you may be picturing in your mind. Think of a small wooden shack that needs to be disassembled. Rather than taking a match and burning the shack down, “burning” body fat is actually akin to disassembling the shack plank by plank, saving the lumber for future projects. The disassembling is done by enzymes and becomes more efficient with larger and more enzymes.

4) Body fat will initially be stored as intra-muscular fat. A person can actually be losing muscle and gaining fat as they age and/or decrease their physical activity. Their weight may even remain the same for a long period of time. Lose five pounds of muscle and gain five pounds of fat and you won’t see a difference on the scale (luckily, as you will read later, the reverse is also true.) This is why it’s very important to judge your weight, not by the scale, but by the composition of your body, fat vs. lean mass.

5) When our muscles run out of room for fat storage we begin to store “subcutaneous” fat, which is fat deposited directly beneath the skin (some appearing as cellulite.) Different bodies have different capacities for storing fat. While some women with a low amount of lean mass may have excess cellulite, some men carry the “I may look seven months pregnant but at least I don’t have cellulite” look.

6) Fat is less metabolically active than muscle tissue. If you lose muscle and store fat, you automatically need fewer calories.

7) First on, last off. Wherever your body chooses to first store body fat is the last place you will burn it off from. And remember – body fat is only burned through aerobic exercise. However, your legs may be pedaling while your body chooses to burn fat from the upper arm!

8) You cannot starve a fat cell. In any starvation period, which can be as short as a few hours depending on how hungry you are, your body will break down muscle before it breaks down fat.

Aerobic Exercise
The “cure” for fat is aerobic or cardiovascular exercise. Aerobic means to take place in the presence of oxygen. As we work aerobically our muscles demand more oxygen for metabolic processes. The blood carries fats (fatty acids) to the muscle cells where enzymes (in the mitochondria) dismantle the fats for energy. This dismantling demands constant oxygen. If our exercise becomes too intense (heavy resistance training, intense sprinting) our body shuts off the fat burning process.

The next plus regarding aerobic exercise is the fact that we not only burn fat while doing aerobic work but we build our bodies into more efficient fat burning machines through steady, consistent aerobic training. Without regular cardiovascular work your body is a tiny little fireplace. With unfailing aerobic work you can build your body into a fireplace that can heat a mansion! This works by building that powerhouse of your cell, the mitochondria. Mitochondria can grow 35% bigger and then split. We can add up to 15% more mitochondria over time.

How much? How long? How often? How intense?
Depending on the amount of body fat you need to lose, the prescription for weight loss is 220 minutes of cardiovascular exercise per week. Sedentary and/or unfit individuals, aside from needing their physician’s approval, should begin with 12 minutes per day, as tolerated. As you progress your goal should be approximately 45 minutes of aerobic exercise (swimming, biking, jogging/running, walking, aerobic group fitness classes, jumping rope) daily. When you reach your body composition goals your will enter your maintenance phase and can cut back on the aerobic work, as tolerated.

Intensity is key in cardiovascular training effecting body composition. You will need to perceive your exertion as at least mildly uncomfortable. As it is impossible for me to give individualized cardiovascular exercise prescriptions in an article, I suggest you use the “talk” rule. If you can carry on a conversation easily, your work is not intense enough. If you can only gasp out half a syllable you’ve stopped burning fat, stopped building your fireplace and your intensity is too high. When you can carry on a conversation (or belt out a tune if you are alone) with some difficulty, your aerobic work is just right. Think Goldilocks.

Resistance Training
Resistance or weight training, when it becomes intense, utilizes glucose (a sugar energy source) for energy, using and building sugar-burning enzymes. When lactic acid production exceeds lactic acid removal (as in intense sprinting or heavy weight lifting) we need to take a rest, “catch” our breath and let oxygen flow back into the deprived muscles. Therefore, performing only intense resistance exercises will not build your body into an efficient fat burning fireplace.

This certainly does not mean I oppose resistance training. I actually love it and it does have its place, when used appropriately and for appropriate goals. Resistance training (body weight work, strength training machines, dumbbells, etc.) creates lean, strong muscle fiber in our bodies. This type of work gives our muscles that beautiful, smooth, lean look. Muscle fiber is more metabolically active than fat and therefore automatically burns more calories. Strong leg muscles aid us in a more efficient performance of our aerobic training (in a roundabout way aiding our fat burning,) strong back muscles lend to good posture and powerful core muscles protect us from back injury and also look great!

One problem people still run into is the idea that they can “spot reduce.” As I stated before, you may be running but burning fat from your arm, not your legs. Following this, you can perform a hundred “sit-ups” or crunches but you will not reduce fat from your abdomen. You may have a nice firm abdomen but without fat reduction (aerobic work) you will still have all the overlaying fat across those beautiful core muscles. I’ve come across quite a few women who believed their resistance training was “bulking” them up. What actually happens most of the time is that the nice smooth muscle, hidden beneath the surface, is pushing against subcutaneous fat, giving a rounded, bulky appearance. Think of a slab of slate, strong, not quite flat, with a bunch of marshmallows lying on top of it. Resistance builds the slate, aerobic burns the marshmallows. Although you cannot spot reduce but you can “spot build.” Some muscle groups are more susceptible to hypertrophy in some individuals so be careful not to overdo it.

Intense resistance training is the maximum of an anaerobic workout and light, easy walking is the minimum of an aerobic workout. Remember Goldilocks and the talk test. Accepting the fact that resistance training is muscle building and cardiovascular exercise is fat burning and fireplace building, we all need to design our exercise programs for maximum efficiency.

What about nutrition?
Nutrition is invaluable. I cannot say enough about healthy nutrition. Proper nutrition begets health, from our hair follicles to our toenails. With good nutrition we will not store additional fat so we will reach our body composition goals sooner. We’ll have more energy, sleep better and have better health in general. But if we lose weight simply through nutrition we’ve done nothing for our muscle fibers or our mitochondria. “Dieting” alone will burn subcutaneous fat but will not burn intra-muscular fat. This basically means that if you are an “apple” shape or a “bowling pin” shape and the only fitness facet you choose is “dieting” you will still be the same shape, only smaller. The only way to make your “diet” (or depravation) severe enough to utilize intra-muscular fat would be under severe conditions, such as those in a concentration camp. With proper fuel through proper nutrition, not “dieting,” our bodies’ chemical reactions work correctly and efficiently.

Therefore, for fitness, nutrition alone is not adequate. This is true for the two reasons we discussed previously. You are not building striking, strong lean muscles and you are not changing your body into a fat burning fireplace.