USING THE NEW FORMULAS TO DEFINE YOUR INDIVIDUAL RANGE, OR NOT.
There have been Earned Runs blog posts recently about the unseen, hidden benefits of high intensity exercise with regard to improved immunity and decreased risk of dementia. One of the articles discussed, based on research in which data was collected more than 4 decades, measured exercise intensity using the Borg Rating of Perceived Exertion (RPE) Scale.
Exercising participants subjectively described the degree of difficulty of a cycle ergometer session effort with an expression like “very light”, “very hard”, or “very, very hard", that corresponded to a number on the Borg RPE scale (likely the original 0-21 scale).
The Borg RPE scale, the original or one of its two revisions, has been used successfully in many research studies. Runners and other exercising athletes are likely to have used a mental version of this RPE scale. Trainers and coaches might refer to this practice as running or training by “feel” to distinguish it from efforts more objectively measured by monitoring one’s own heart rate
Because the intensity level at which exercise is performed is increasingly seen as key to obtaining health benefits, like weight, and blood pressure and glucose management, how do we know we are at the correct level to achieve a specific outcome? How do we know we are working hard enough, or not overly harder than what we ‘perceive’ is in the needed range? Is a heart rate monitor required?
Probably not. However, if checking your individual perception of effort against a heart rate monitor will help build confidence by taking away uncertainty, go for it. Use the Borg RPE scale to describe the subjective difficulty of a session and at that time record a heart rate monitor reading. Check that reading against a target heart rate range of 65-85% effort. After that exercise by feel, checking against a heart rate monitor reading only intermittently.
An article by Paige Waehner, “How to Calculate Your Target Heart Rate Using the Karvonen Formula” for verywellfit.com helps with that process. Waehner describes the popular and simple Karvonen method of calculating Maximum Heart Rate (MHR): 220 beats per minute - minus your age.
The MHR is the number from which different intensity levels are derived, by multiplying it times the desired percent effort level. The values for 65%-85% effort by age are likely to be posted on exercise equipment in your fitness center. Thus, 200 bpm would be the MHR of a 20-year old person (130-170 bpm range), 175 bpm of a 45-year old (114-149 bpm range), and 150 bpm of a 70-year old, (98-128 bpm range) not taking into account fitness level or gender. This method is now thought to be inaccurate.
Waeher explains in detail how to calculate MHR based on your individual resting heart rate by using UPDATED formulas for men [206.9 – (0.67 x age) ] and women [206 – (0.88 x age)], which adjust for gender, resting heart rate, and age, and then how to calculate the rate for your 65-85% intensity level range.
Waehner doesn’t list a reference for the updated women’s formula.
Tara Parker-Pope discusses the research that generated the re-calibrations for both men and women in a 2010 nytimes.com WELL blog. In Parker-Pope’s piece she identified the lead researcher at Northwestern University in Chicago as the source of the new women’s formula, Dr. Martha Gulati. The original publication in the journal Circulation was located by Earned Runs; see the very last section “Clinical Perspective” for explanation of the new formula.
The specific source of the men’s formula was not provided in either piece although the work of University of Colorado researchers was mentioned by Parker Pope.
Do you fear doing the math involved in determining intensity level by heart rate? The parting message from the NYT WELL blog might be for you. “Everyone kind of has their own natural pace”, expert Dr. Tim Church is quoted as saying. Keeping track of a number may distract some from sticking with an exercise program that’s enjoyable, so skip it and work as hard or little, and as long as you wish.
RUN & MOVE HAPPY!
http://www.northwestern.edu/newscenter/stories/2010/06/heartrate.html (news release)
http://circ.ahajournals.org/content/122/2/130.long (go to very last section “Clinical Perspective”)
BRIDGE TO PHYSICAL SELF
Running, walking, and fitness activities enable us to experience our physical selves in a world mostly accessed through use of fingers on a mobile device.
EARNED RUNS is edited and authored by me, runner and founder. I began participating in road races before 5Ks were common. I've been a dietitian, practiced and taught clinical pathology, and been involved with research that utilized pathology. I am fascinated with understanding the origins of disease as well as health.
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