Adam Friedman, Mirror Fitness Columnist
Has the amount of time you’ve put into your cardio efforts paid off? Do you have that lean and fit body that you expected by now? If you are not getting results as fast as you’d like, the reason may be more related to time than you think.
Adjusting the speed in your workout can often make the difference to get results. Whether you need to be going slower or faster, or more likely a combination of both, is determined by your Target Heart Rate (THR) zones, which are a range of low, medium, and high heart beats per minute during exercise that indicate your intensity level, and therefore the outcome of your training.
Your THR zones are your own personal parameters to generate weekly improvements to your fitness level, and realizing your potential. It is those parameters that can give you a piece of mind in knowing that your time and effort are paying off instead of being wasted (see calculations chart).
Appropriate use of your THR zones allows you to quantify your intensity level, which indicates how your metabolism is being affected. Each THR zone is based on a specific percentage of your Maximum Heart Rate (MHR). A simple calculation, called the Karvonen Formula, can be used to determine a ballpark of your MHR and your THR Zone.
But before you do the calculation, you must first know your Resting Heart Rate (RHR). The most accurate resting heart rate should be measured first thing in the morning after a full night of rest, and before getting out of bed. Find your pulse on either your wrist or neck and count the number of beats in 15 seconds and multiply that number by four, which will equal your RHR.
If you are a stickler for precision and prefer to find out your exact MHR, you can either ask your doctor to administer an exercise stress test, or a local fitness clinic, such as Advanced Athletics, that can administer a VO2 Test. Both tests involve a gradual increase in exercise intensity on a treadmill or stationary bike to measure your heart and lung response. At the end of each, you will have a full report of your maximum heart rate, exercise parameters, and fitness level based on how well your body uses oxygen.
For healthy individuals, the Low Intensity Zone is in the vicinity of 65 percent of their maximum heart rate. This intensity level is considered an exercise recovery heart rate because the metabolism should be functioning efficiently at an aerobic capacity. This means that the constant presence of oxygen is plenty sufficient to maintain the metabolic needs for a long duration. Your body will also use a larger percentage of fat to be broken down for energy than at higher intensities.
The Moderate Intensity Zone hovers around 75 percent of the MHR. As you increase intensity to this zone your body requires more anaerobic energy (without oxygen), and your heart and lungs are more challenged to meet the oxygen demands. You can maintain this zone for a long period before becoming fatigued, and also begin to make fair improvements in your cardiovascular conditioning. At this intensity, since your body requires a faster supply of fuel for energy, fat is broken down less, and sugar becomes predominant as the heart rate and respiration increases.
At the High Intensity Zone, your exercise heart rate can be at 85 percent of the MHR, and sometimes a little higher or lower depending on your effort level and health status on that particular day. When incorporating this zone in your cardio training on a consistent basis, the heart and lungs are challenged in a way that significantly improves the body’s uptake of oxygen, which is a highly valuable marker of achieving better fitness.
In this zone, the body’s demands go well beyond what oxygen can provide, and is primarily functioning in an anaerobic state. Breathing will become more rapid, and it will be difficult to maintain the high intensity for a long period of time – this is partly an energetic biochemical process resulting in the production of a byproduct called lactic acid, which may create a bit of a burning sensation in our muscles, and may ensue fatigue. However, it’s not dangerous, and a mental tolerance can be built with repetition so that you can last longer at high intensities.
Although the High Intensity Zone may not sound like a whole lot of fun at first, your body and mind will adapt, and your body will internally release endorphin hormones that can give you a “euphoric” feeling during and immediately after.
Now that you understand the difference between the three THR zones, what then? A general rule of thumb for everyone is cardio training begins with a 10-minute warm-up period to gradually raise the heart rate to the THR Zones. Follow this warm up with a specified time frame of staying within the THR Zones according to the objectives of the workout and progression. Finish with a 5-minute to 10-minute, cool-down period to gradually lower the heart rate and relax the system.
A weekly schedule of cardio training can consist of at least one or two interval-training workouts, as well as one or two alternating standard cardio training days.
An interval workout is what will make the biggest difference in your fitness level. It usually lasts around 15 minutes in between the warm-up and cool-down. This is when you are intermixing short bursts of sprints for 30 to 60 seconds, followed by 60 to 120 seconds of recovery, and repeated. The objective is to reach one of your higher target heart rates (75 percent to 85 percent MHR) followed by a recovery HR (65 percent MHR). Because of the high intensities and stress on the body, it is recommended to alternate with standard cardio recovery days.
The Standard Cardio workout can be performed at an intensity between 65 percent and 75 percent for a duration of at least 30 minutes. This is where endurance is gained, and a higher level of fat is utilized as the duration reaches 60 to 90 minutes.
To keep track of your heart rate during exercise, I recommend using a heart rate monitor for a safe and efficient measurement. A decent quality monitor can be bought at any local gym, or sporting goods store for $60, and is a worthwhile investment.
I encourage you to apply your Target Heart Rate Zones to your routine starting with your next workout, and get on the fast track to better fitness.
Adam Friedman, CSCS, CN, CMT is a kinesiologist, certified strength & conditioning specialist, certified nutritionist, and certified massage technician. He is the founder of Advanced Athletics, Inc. located right next door to the world famous Gold’s Gym in Venice, on the corner of Sunset Ave. and Hampton Drive, one block east of Main Street. To schedule a complimentary assessment, please call 310.396.2100 or e-mail Adam at firstname.lastname@example.org. Otherwise, to learn more, visit www.advancedathletics.com.