FIND A FORMULA THAT ‘FEELS’ BEST TO IDENTIFY YOUR PERSONAL TARGET RANGES AND TO MEET FITNESS GOALS. There have been Earned Runs blog posts in the past about the 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 may have used their own version of a perceived exertion scale without knowledge of the formal Borg research tool. Trainers and coaches would refer to this practice as running or training by “feel” to distinguish it from efforts measured objectively by heart rate.
Because the intensity level at which exercise is performed is increasingly seen as key to obtaining health benefits, like weight control and blood pressure and glucose management, how do we know by ‘feel’ that we are at the correct level to achieve a specific outcome? How do we know we are working hard enough or not overly hard when we use ‘perceived’ exertion measures to guide training?
Is a heart rate monitor required?
Probably not. However, if checking your individual perception of effort against a heart rate monitor number 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. After that, exercise mostly by ‘feel.’ Check a heart rate monitor intermittently as needed to allow for improvement or detraining. What feels hard at the start of a training program will be considered easy in later weeks. Conversely, what was easy during a training peak might not be so after months of not working out.
An article by Laura Williams, “What is My Max Heart Rate and How Can I Use It In Training?” for runnersworld.com helps with that process. Williams describes the pros and cons of using the popular and simple (Fox) method of calculating Maximum Heart Rate (MHR): 220 beats per minute - minus your age. She includes other formulas as well.
Multiplying your MHR by a desired percent effort will determine your training level target heart rate. The values for 65%-85% effort by age are likely to be generically posted on exercise equipment in fitness centers. Thus, the 65-85% effort range of a 20-year old person with a 200 bpm MHR would be 130-170 bpm, 114-149 bpm will be 65-85% range for a 45-year old with an MHR of 175bpm, and 98-128 bpm will be the range for a 70-year old with MHR of 150bpm. However, it is thought that this simple Fox calculation of MHR doesn’t take into account fitness level or gender. And the range posted on machines is likely too broad to help figure out intensity level/zone.
An article by Paige Waehner for verywellfit.com explains in detail how to calculate MHR based on your individual resting heart rate by using UPDATED formulas compared with the Fox formula. For men and women [206.9 – (0.67 x age)], the Tanaka formula has been developed, and, specifically for women [206 – (0.88 x age)], the Gulati* formula. Another article by the same author posts a Target Heart Rate Chart for low, moderate, aerobic zone, and vigorous intensity training based on the Tanaka formula (which for most purposes can be rounded off to 207 - (0.7 x age), according to age.
Another article on the topic, authored by John Bobalik for active.com uses the Fox formula to determine MHR and then the Karvonen method (which requires you to know your resting heart rate) to determine the various target heart rates for training/effort levels:
-aerobic range for fat burning (50-75% MHR)
-aerobic range for fitness (75-85% MHR)
-aerobic-anaerobic threshold (85-90% MHR)
-anaerobic range for fitness (90-100% MHR)
The math calculations are clearly explained with examples in Bobalik’s piece, and I found it the most useful of all the articles cited. A different site provides a calculator which will do this after you insert numbers for MHR and resting heart rate.
Some women may wish to use the Gulati* formula to determine their MHR. The maximum number is a bit lower and the target ranges of beats per minute per training level tend to run a bit lower. A 70-year old female’s MHR would be 150 bpm by the Fox formula and 144 bpm by the Gulati formula, which would lower the target goal effort for each zone.
Men and women hoping to get the most out of themselves may wish to use the Tanaka formula. A 70-year old’s MHR would be 150 by the Fox formula and 160 by the Tanaka.
Williams’ runnersworld.com piece reminds readers that however calculated, MHR formula-derived rates are estimates that should be used as guides to training. The target numbers may need to be adjusted up or down depending on perceived effort “as time goes on and you adapt to training”. Again, it seems that ‘feel’ plays a deciding role in how we train.
Do you want to avoid formulas, calculations, and target heart rates altogether when determining training effort intensity levels? 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. Skip the math and work by “feel,” as hard and as long as you wish, if a non-formula approach helps you meet your fitness goals.
RUN & MOVE HAPPY!
*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 Tanaka formula was not provided by Parker-Pope although the work of University of Colorado researchers was mentioned.
(compares Fox, Tanaka, and Gulati and the Karvonen method)
(uses 206.7 minus (age x 0.67 formula)
Target Heart Rate Calculator chart using Tanaka MHR formula
(uses 206.7 minus (age x 0.67 formula)
(Karvonen calculator tool)
Explanation of resting heart rate, with fitness charts by gender, age
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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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