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Keep your muscles while stengthening your heart

By Stephen Kelly

There are several great mysteries in life, like who built Stonehenge, what's up with the Loch Ness Monster, and is it OK to wear white after Labor Day. But for athletes perhaps the biggest mystery is how to get the fat-burning and cardiovascular benefits of a good aerobic routine without losing hard-earned muscle.

Herein lies one of the more delicate balancing acts in fitness. Too much cardio and you lose those pesky love handles but shred muscle. Not enough and you keep the bulk while retaining a midsection the Michelin Man would be proud of. Fearing muscle loss, many strength trainers often do little or no cardio. That's a bad idea.

You need an effective aerobic routine not just to build a killer body, but also to achieve and maintain overall good health. Besides the obvious fat-burning benefits, a good cardio routine increases your metabolic rate, helps decrease levels of dangerous low-density lipoproteins (also known as "bad" cholesterol), lowers blood pressure, and bombards your brain with endorphins that give you that "I'm the king of the world" feeling of euphoria and wellbeing.

With proper planning and focus, you can achieve a balance and be both fit and built. You just need to focus on the intensity and frequency of your cardio workouts and keep a close check of your heart rate as you train aerobically.

To get started, you will need to know your maximum heart rate (MHR) in order to determine the intensity of your aerobic workout. The easiest way to determine your MHR is through a simple formula of subtracting 220 minus your age to determine an approximate MHR. For example, a fit 35-year-old man will have a MHR of 185.

Whether you're cardio training outdoors or at the gym, you will need to track your heart rate as you train aerobically. Most treadmills, exercises bikes and elliptical machines come equipped with heart rate monitors, but these can be wildly inaccurate, particularly if equipment is situated close together, as it is in most gyms. Want a better method? Invest in a heart rate monitor that you wear on your body. Heart rate monitors cost anywhere from 30 to 300 dollars, and you can count on these monitors to be very accurate.

Serious endurance athletes such as marathoners, cyclists, and triathlon competitors and the like will have to live with the fact that they will lose muscle in favor of a leaner, wirier physique. That's because preparing for endurance competitions requires the type of intense aerobic training that will burn muscle over time. That said, if you don't fit into the endurance demon category, you can control your muscle loss while training aerobically by choosing from different levels of cardio intensity:

Level 1: Big Muscle, Low Fat
If you want to do just enough cardio to burn fat without losing any muscle, you should do cardio three times per week for 30 to 45 minutes at 50 to 75 percent of your MHR. At this rate, you will keep all of your muscle and burn enough fat to trim that spare tire, meaning a fit 35-year-old man will need to keep his heart rate between 90 and 135 BPM.

Level 2: Heart Like a Racehorse
If you want to develop the cardiovascular system of a racehorse and still retain mass, you should do cardio for to five times per week from anywhere between 45 to 60 minutes at 60 to 85 percent of your MHR. With these goals in mind, the aforementioned 35-year-old man with a maximum heart rate of 185 should set his target heart rate between 111 and 157 beats per minute (BPM) to achieve this result. Note you may lose a little muscle at this level of intensity; that's the tradeoff for being in kick-butt cardio shape.

Smart Scheduling
One of the primary causes of muscle loss due to cardio training isn't the fact of the aerobic activity itself; it's the scheduling of cardio back to back with strength training. That's because your body needs to restore the blood glucose and glycogen it gets from carbs that are depleted during aerobic training, and it will take what it needs from fat and proteins stored in muscle, defeating the purpose of lifting weights. For optimal results, you should arrange your weight lifting and cardio sessions at least six hours apart. That gives your body sufficient time to recover between routines and prevents muscle loss due to cannibalization.

If your busy life prevents you from breaking out your cardio and strength training into two separate sessions, be sure to eat a meal or snack that is high in carbohydrates within an hour after working out. That will help restore the blood glucose and glycogen your body lost during aerobic training, and will keep it from hitting those fat and proteins stored in muscle. There are many replenishment drinks sold in gyms and supplement stores, but ideally you should get these carbs from high-glycemic foods like bread, brown rice, bananas, potatoes, and cereals.

Speaking of nutrition, as a serious strength trainer you should also be eating a lot of protein to help keep your muscles nourished and growing. Your body derives muscle-building amino acids from proteins, and putting yourself through a grueling workout routine without a steady influx of protein is like trying to drive a car without gas. A serious athlete looking to build or keep mass should eat protein every three to four hours, whether through pure sources derived from foods or through protein shakes or powders.

Stephen Kelly is a San Francisco-based freelance writer and NPTI-certified personal trainer. He trains his clients at Gold's Gym in San Francisco's Castro district.