In my last post I talked about the advantages of doing more interval-type of training when it comes to cardiovascular activity, as opposed to traditional “fat burning” cardio. Now I will help you understand the basic ranges for an interval cardio routine. You will first need to know what your resting heart rate (RHR) is. To do this, lay down comfortably without much movement for about ten minutes. After ten minutes have passed you can check your pulse by either using a heart rate monitor or measuring your pulse manually. To do this manually simply use the pads on your index and middle fingers to locate your pulse either on the inside of your wrist (radial pulse—about an inch down from your wrist near the thumb-side edge) or on your neck (carotid pulse—in the hollow between the windpipe and the large muscle in your neck). Make sure to keep the pressure light. Once you find a pulse, using a second hand on a watch or clock, count how many beats you have in 15 seconds, then multiply this number by 4. (You can also do this for 10 seconds and multiply by 6.)
Once you have your RHR, you will plug this into the Karvonen heart rate formula to figure out what your base ranges are (these may change depending on your level of conditioning). The Karvonen formula is ([220 – age – RHR] × 60–90% + RHR]). Simply plug your age and your RHR into this formula along with the intended working effort (the percentage of workload). If you are de-conditioned (not having worked out in over six months or have any health concerns) I would suggest figuring out your ranges for a percentage between 65% and 75% (note: for someone who is not acclimated to exercise induced stress this level of work may push the body so it’s more work than if you were conditioned and working in this range, which is more of the fat burning zone). If you consider yourself to be in good condition (you work out with some regularity and are fairly healthy) I would suggest working in the range of 75–85%. And if you are in excellent condition (work out rigorously already and are healthy) I would suggest working in the 85–90% range.
Note: It is recommended that you visit your physician for a checkup before starting any cardiovascular program (or any exercise program for that matter). Even if you have been doing cardiovascular activity already, it is recommended to visit your doctor before starting higher intensity workouts.
Once you have determined your working range, find a cardiovascular activity (treadmill, bike, elliptical, running/jogging outside, etc.) to test your working range against your base range. This activity we will call “effort.” The range you came up with using the formula is simply to give you some basic guidelines and to know what to shoot for. I always recommend starting any activity with about two or three minutes at a very light pace to warm up. Once you are warmed up, start to increase the workload/effort (on a bike or elliptical you would increase the resistance, the treadmill or outside jogging would require you to increase your speed) about 25 percent from your warm-up speed or go up one or two levels. (In many cases you might just have to increase one level at a time as going from level one to level two might be the only jump you can make.) Do this for about a minute and evaluate how you feel. Pay close attention to your breathing as well as other things like whether you feel nauseous or dizzy. Your goal with this is to work toward the top end of your predetermined working heart rate range and hold that for one minute. However, the most important factor here is not your heart rate but your ability to breathe. Once you get to a point where you are becoming winded, you are nearing your high end, and once at this point you should try to hold that for a minute.
If increasing your effort did not get your heart rate and breathing rate up after one minute, then increase the effort another 25 percent (or another level). Do this for another minute and see if you start to become winded. Continue raising the effort every minute until you start to become winded. Once you are winded, continue this pace for one additional minute. Check your pulse at the beginning and end of the final minute. After the minute of work at this highest level is complete, start your cool-down. Bring the effort down to the lowest level you can work at and feel comfortable (walking at one mile an hour on the treadmill might be too slow). Notice how fast your heart rate starts to come down. Within the first minute your heart rate should drop about thirty beats—fifty if you are in good condition. If your heart doesn’t come down thirty beats in the first minute, don’t fret—you just have some work to do. Continue cooling down for two minutes, then get off the machine or stop your activity altogether. Sit down comfortably for one minute, and then check your pulse again. Your goal is to be at about 100 beats per minute. If you are not there after the one minute of rest, continue sitting and checking your heart rate every minute until it recovers.
If you are fairly de-conditioned it might take you a long time to recover. If it takes you longer than five minutes to recover (to get to 100 bpm) then you may want to consider that the effort you did was too high for the time being and you should set your working range to a lower level. If you recovered inside five minutes, then your effort is appropriate. If you recovered before your initial two minutes of cool-down were up, then you may want to consider working at a slightly higher range.
Once you have determined your working range, you can create your workout. Always start with a light two- or three-minute warm-up. After you complete your warm-up, go to or near the high end of your working level of effort. Your goal is to do this level for two minutes and to be close to having to stop because of oxygen debt (meaning you are running out of breath) by the end of your two minutes. You should want to stop because you no longer have the ability to continue, not just because you have reached the two minute mark. Once you are done with your two minutes, bring your effort down as low as possible and cool down until your heart rate recovers to about 100 bpm. My simple rule is, if my heart rate does not recover inside five minutes (either because I was already stressed from the day or a workout or some other factor) then I have stressed my body enough to send the appropriate signals to activate the “lean signal.” Once you recover, you can repeat this process until you have worked for about twenty minutes. I often include my warm-up and final cool-down in this twenty minutes and usually get about four sets (a set is one working range and one cool-down) in. Some days I get more, and there are days I only do one or two sets. I always listen to what my body will allow. More is not better if my body is not recovering well.
Note: If you had a hard time recovering after your first working range, then you may want to start your workout very lightly by doing intervals at a medium pace (maybe about 60 percent effort) for two minutes, never really getting out of breath, and cool down for two minutes, going back and forth (two minutes on, two minutes off) for the twenty minutes. Once you are better conditioned, you can try to challenge yourself a bit more during your workout and see how you recover. This level of interval training will do wonders if you are de-conditioned.
Remember, always listen to your body. It is always trying to communicate with you. If something doesn’t feel right, then seek professional assistance immediately. It’s better to be safe and smart than sorry.