Making the most of your cardio workouts

Volume One, Issue 21, February 16 - 22, 2007

By Greg Rothman, M.S. P.T.

If you’ve been following my column, you’ve been introduced to the concept of “synergy,” the three elements of any successful fitness program that work together to give you the results you want — building lean muscle, moderate cardiovascular exercise and the right nutrition — and you read about the first, building lean muscle, in last week’s column. This week, I’ll help you to make the most of your efforts at the second part, cardiovascular exercise, and give you the strategies you need to avoid feeling as if you’re just “running on a treadmill” without getting results.

To optimize your time spent doing cardio, you’ll want to be familiar with three concepts: type, intensity and timing.

As a fitness professional and gym owner, I’m often asked what is the best type of cardio — treadmill, elliptical, stair-climber or bicycle. The answer is: all of them. If you use only one type of machine, your body will quickly adapt and give you diminishing returns for your efforts. So, change the type of cardio you do regularly. In fairer weather, outdoor jogging, rollerblading and cycling can be as good as the machines. The bottom line is not what kind of activity you participate in, but the effect it has on your heart rate, which brings us to the concept of intensity.

To maximize your results, you’ll want to monitor your heart rate during exercise, either by manually taking your pulse (not very practical while exercising), using the built-in handheld device standard on most commercial cardio machines, or using a heart-rate monitor that can be purchased for as little as $50 at a sporting-goods store. Once you’re equipped with a tool to monitor your heart rate, use it to help you exercise within a range of intensity, which for each person is equivalent to a “target heart zone” (THZ), which is 65 to 85 percent of your maximum heart rate (MHR). (To calculate your MHR, subtract your age from 220. Divide that number by both 0.65 and 0.85 to yield your THZ.)

The conventional wisdom is that you burn the most fat by working at the low end of your target zone (the 0.65 figure), but this is misleading: You do burn the highest percentage of fat at the low end of your target zone, but you burn fewer total calories and, therefore, fewer fat calories. Instead, optimize your results by doing what is known as “interval training,” or working for a minute or two at the high end of your target zone (after a five-minute warm-up), then a minute or two at the low end — and repeating this throughout your cardio workout. To make progress from workout to workout, expand your time in the high end of the range, and decrease your time in the low end. By exercising in this way, you will not only condition and strengthen your heart optimally, but you will also burn more calories while you’re doing the cardio — and in the hour or two following your workout.

I’m also frequently asked what are the best times of day to do cardio workouts. The answer is twofold: If burning fat is a goal, as it is for most of us, on days when you are not also doing a strength-training workout, do your cardio within 30 minutes of waking, on an empty stomach. Because you don’t eat overnight, your blood sugar is lowest in the morning and you have very little stored sugar to energize a cardio workout. The result: Your body will “fuel” your workout by burning stored fat. If you use this effective strategy, make sure you’re aware of how your body feels. None of my clients have ever had a problem training this way, but if you feel any lightheadedness or weakness, that is an indication that your body isn’t ready for it, and you should stop immediately.

On days when you are doing both a strength and a cardio workout, it is best to have a meal roughly one hour before you exercise, and to perform the strength workout first, followed by the cardio. The reason for this is that you will need fuel (sugar stored in muscles) to power your more demanding strength workout. Once you’ve burned the stored sugar and begin doing your cardio exercise, your body will again rely more heavily on burning stored fat.

Once we understand the best strategies for doing cardio exercise, it becomes easy to optimize our workouts and reap the results. In my next column, I’ll discuss the third part of the synergy: sound nutrition. Once you have all the parts of a successful fitness program at your fingertips, there will be no stopping you. You’ll have all the tools you need to add lean muscle to your body, burn stored fat and get your metabolism running at its fastest rate ever.

Greg Rothman, M.S. P.T., is the owner of emPower Fitness Studios (emPowerFitnessNYC.com). He received his masters degree in physical therapy from Columbia University and has 15 years’ experience in the rehabilitation and fitness fields, most recently as the personal training manager and top-level trainer for Equinox Fitness Clubs in New York City. SEND YOUR QUESTIONS about nutrition, fitness and sports injuries/rehabilitation to Greg at emPowerFitness@aol.com.