Cardiovascular Training: Try It, You Might Like It

By Michael Krueger
After completing an initial fitness assessment, I frequently have to bring up the subject of cardiovascular training. I almost always get the same response: a wrinkled nose and rolled eyes. Despite everyone knowing that heart and lung function is critically important not only for firefighting but to staying alive, I still get the same reaction.
People who may be excited about strength training are often not equally enthused about cardio. The objections I hear most often are that it is boring and it takes too much time. The modalities are frequently at issue as well. I hear how people hate to run, swim, bike, row, stair climb, and even walk. I’m going to recommend something that will cut down on the amount of time you have to spend doing your cardio training. It is very effective and may be somewhat more mentally engaging as well. 

High-Intensity Interval Training (HIIT)

Interval training has been shown time and again to be safe and effective and, for trainees who complain about boredom, more enjoyable than conventional, long, slow aerobic training. I won’t bore you with the statistical data, but even people with severe heart disease and advanced metabolic syndrome have showed vast improvements in heart and lung function, blood glucose levels, cholesterol levels, and a myriad of other markers for health and fitness. This was all accomplished on a regimen of less than 30 minutes of training three days a week.

The first fact you will need to accept is that there is no free ride. Any form of interval training requires effort–a lot of effort. Second, because it is so hard, you need to believe that it is worth the effort, so motivation is an absolute necessity. These two points do scare off some people, but as a firefighter you have already shown that you aren’t afraid of much of anything and you certainly have the drive to do what needs to be done. Once you see how beneficial interval training can be, I don’t think motivation will be an issue; in fact, you might even enjoy the challenge.
The science behind HIIT isn’t complicated, but it isn’t particularly good reading, so I’ll give you a condensed explanation. Let’s use running as the example. Basically, when you run as fast as you can, you are pushing your entire body to its physical limits. Your heart and lungs are supplying as much oxygen as they can to the working muscles. You are activating both slow and fast twitch muscle fibers and, because you are demanding more from your body than you have previously, you are creating a huge disturbance in your muscles homeostasis, thereby causing the activation of your body’s stress response.
Your body doesn’t like this disruption and works hard at finding ways to adapt to the increased stress. Over time, you will become more efficient at converting lactic acid back into energy. Your heart will become stronger, pumping more oxygen-rich blood to the working muscles with every stroke. Your lungs will become more efficient at the transfer of oxygen and the venting of carbon dioxide. Your arteries will become more flexible and resilient. Your metabolism stays revved up for hours after you are done working out, which your body will respond to by burning additional fat and carbohydrates. You will use your fat stores more efficiently while preserving lean mass.  

Basic HIIT Application

There are many different protocols to choose from when it comes to HIIT. It is most often used with running, biking, and rowing but can be applied to any activity in which you can control the intensity. The work periods can run from 15 seconds to two minutes with very short to moderately long recovery periods. The idea is that you “accumulate fatigue,” each work period getting harder than the last one, never giving your body the chance to recover completely until the workout is finished. You may have to do some experimenting to find what you like and what works best for you. Rest assured though, whichever variant you eventually chose, if you work very hard it will be very effective.
Arguably the most difficult HIIT program is what is known as the “Tabata Protocol.” It is the original HIIT protocol created for, and tested on, the Japanese National Speed Skating Team. It requires that you warm up for five minutes, then work at your absolute max (it was initially tested at 200 percent of VO 2 max) for 20 seconds and recover for only 10 seconds for 10 repetitions or a total of five minutes and then cool down. This is truly a brutal workout because of the shortness of the recovery interval and the intensity of the work period, but it does work incredibly well. If this appeals to you even a little bit, you are sure to achieve great things with HIIT.
On the other end of the spectrum is two minutes of near max work followed by two minutes of recovery. This will work as well, provided the work intervals are applied with the proper intensity. This too is an extremely difficult protocol, leaning a bit more toward endurance. If you have been a distance runner, this might appeal more to you than all-out sprints. The work interval is done at a pace 10 to 20 percent faster than your current 5K pace. Some runners modify it by doing 400-meter repeats with a 400-meter recovery run in between each max effort. This is an equally physically unpleasant but highly exhilarating and effective way to train. The recovery interval can range from a 10-second dead stop by jumping to the sides of a treadmill belt before jumping back on the moving belt for another 20-second work interval to walking, pedaling, or jogging at a slower pace. It depends on your fitness level, your chosen protocol, and your personal preference. Remember that the recovery period is not meant to allow you to achieve full recovery but just enough that you may finish the next work interval. Once again, be honest with yourself and do the best you can. Always work to increase the effort in your work interval or to shorten your recovery period.
Whichever activity you choose, it will be based on your personality, your fitness level, and your overall goals. Don’t let anyone else’s choice influence you. If you find what works for you and stay with it, your results will be comparable to those of other HIIT devotees and superior to steady state exercisers.  

Personalizing HIIT

You may find that it doesn’t take much to challenge you when you first begin HIIT training. That’s to be expected. You are where you are and rationalizing or making excuses won’t change that. With all exercise, starting with what you can do right now and progressing is the key, and HIIT is no different. Even if you have been working out regularly, you will find HIIT difficult and humbling.

Whether you are going for a 20-second sprint or a slower two-minute pace, you begin with whatever your maximum is right now, and then you back off and recover. At first you may choose a recovery period that is based on your breathing, rather than a specific distance or number of minutes or seconds, before beginning your next work interval. You are aiming for about five to 15 minutes of work time (not including the recovery intervals) per workout, two to three times per week.
For a little more variety, you may also change the length of time in a work interval within a workout. For instance, you may start with a two-minute work interval and end with 30 seconds. Or perhaps start with 30 seconds and end with two minutes. It is an infinitely variable protocol, and you are in charge of its creation.  

Staying Honest

Perhaps the most difficult aspect of HIIT, aside from the hard work, is that you are in charge of the intensity. You must be very critical and honest with yourself when creating your program and critiquing your progress. You must monitor how hard you are working and how long you are resting; there are no charts to go by, just how you are feeling during the workouts. This can be problematic if you are not being completely honest about your effort.

If you are going “slow and slower” as your work and recovery intervals, your results are going to somewhat less than stellar. If you are pushing so hard that you are throwing up during the workout, you are going to get ill and burn out. If you need a workout partner to help you assess your effort, by all means recruit someone you trust to help you out.

You Can’t Argue with Results

Give HIIT a fair test. If you stick with a HIIT protocol for eight weeks, you will achieve an improvement in your fitness and health that will astound you. Every aspect of your life will be positively affected. This type of training has even been shown to improve brain function through increased blood flow and oxygen delivery. Because it is time effective, you won’t need to spend hours pounding away on a treadmill. This will free you up to spend more time with your family on your off days and you will have more time and energy to work on your firefighting skills when at the station. Talk about a “win/win” situation.

Michael Krueger is an NSCA-certified personal trainer. He got his start in fitness training while serving in the United States Coast Guard. He works with firefighters and others in and around Madison, Wisconsin. He is available to fire departments, civic organizations, and athletic teams for training, consulting, and speaking engagements. He has published numerous articles on fitness, health, and the mind-body connection and was a featured speaker at the IAFC’s FRI 2009 Health Day in Dallas, Texas. E-mail him at 

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