Know Your Zones

Ever started a weight loss program, kept up the same routine for a long time, but notice the results dwindling? More often times than not, it can be difficult to achieve consistent results due to poor understanding proper overload during your training. As corny as it may sound, the only way to get better is to challenge your body (overload). This can be as simple as walking faster on the treadmill, more incline, more resistance on the bike, anything that makes the exercise more difficult. Overload leads to adaptation, adaptation leads to result, in our case; weight loss. However, what most weight loss patients lack is a proper variable to monitor this intensity. Many patients use calorie estimations on aerobic equipment or rate of perceived exertion (RPE) to monitor intensity of their workouts. While variables like RPE and estimated calories expended are most certainly a start, limitations include lack of validity and reliability. One workload variable that can control for such limitations is heart rate (beats per minute or bpm).

Heart rate zone training (HRT) is defined as the integration of the heart rate variable (bpm) into a training program to measure intensity of a workout (Friel, 2009). Historically, HRT has been primarily used for endurance athletes such as runners, cyclists, or swimming to improve performance gradually over time. More recently, HRT has emerged as an effective strategy for optimizing training efficiency for individuals trying to lose weight during their aerobic exercise (walking, cycling, stairs, elliptical, etc.).

Based on a previous blog entry, “Pain does not always equal gain”, we have established that proper intensity for weight loss during aerobic exercise should be lower and intensity should be longer. It is now important to take this one step further and quantify the measurement of this intensity. Typical quantification of exercise is done so in an absolute format. For example, a patient starts a weight loss program that includes walking on the treadmill at 3.0 mph for 30 minutes, 3x/ a week. Let’s say they are motivated to keep this routine up for 8 weeks. However, it is often overlooked is that their body will adapt to this initial overload, and therefore will burn less calories each week (Brooks and company, 2014). Burning less calories each week will minimize the calorie deficit, leading to a slowing of weight loss.

Now let’s take that same individual and put them on a relative HRT program. At RPTWL, we assess HR zones using indirect calorimetry. More simply put, we measure oxygen consumption and ventilation during exercise to assess exactly how many calories you're burning at every heartbeat. Let's take that same patient and put them on the same 3x/ a week 30 minute program, but instead of saying walk at 3.0 mph, we prescribe maintaining a HR of 110 BPM. The same progression will happen over time in terms of initial overload and adaptation. However, different from our first example, this patient will have to continuously increase the speed and incline of the treadmill to achieve that 110 BPM. In conclusion, their calorie expenditure will not be compromised over time, as they are continuously increasing the absolute workload (speed and incline) to achieve the prescribed HR zone.

Furthermore, HRT allows the individual to control the choice of their modality (treadmill, bike, elliptical, etc.). When you are prescribed a HR zone, it is all about doing whatever it takes to get in that zone, however you choose. Patients are not limited to one modality like our first scenario with 3.0 mph of treadmill walking. HRT provides the flexibility and practicality to personalize your exercise program and freedom for variety while still being effective.

They say the best program is the one you keep doing. At RPTWL, we feel HRT is not only the most effective, but safest way to measure the intensity of your exercise. For more information on how to assess your most optimal HR zones, please reach out to one of our Exercise Physiologists.