By Shannon Grady - Physiologist
“Despite 61 million wearable fitness devices being sold worldwide last year, new data has found that the majority of people working out are still not fully clear on how to use a heart rate monitor to maximize their fitness goals. The research from Polar, a creator of wearable sports and fitness technology, has revealed that athletes, regardless of fitness level, are, on the whole, only passively tracking their heart rate rather than actively applying it to workout regimes.”
- Dave Claxton “SportTechie” October 2017.
Although the use of heart rate monitors has been around for 30+ years, and is the most common biometric used in fitness and performance, many coaches, athletes, and fitness trainers are still using heart rate data ineffectively for maximizing performance and weight loss. Throughout my years of experience working with a myriad of coaches, athletes, and fitness enthusiasts, the most common thing I stress is the importance of the “HOW” and “WHEN” to use heart rate in training.
Use of heart rate is ONLY effective when used correctly.
Get tested.
Use heart rate during low intensity, continuous efforts (recovery or aerobic sessions) only.
Do not use heart rate during intermittent high intensity interval exercise or training.
ONLY by testing will one know their actual individual heart rates.
Using heart rate formulas based on 220 minus age will be very conservative ranges for most active people, especially athletes. Accurate information on appropriate zones can be done via physiological profile and max heart rate testing. Physiological Profile testing (PPT) is a controlled, continuous protocol that utilizes various metrics such as speed, power, heart rate, and blood lactate to measure physiological capacities in the areas that are pertinent to the events in which the athlete is competing. Max heart rate testing can be done by doing an incremental maximum exercise test in various modes such as running, biking or rowing.
Heart rate, not pace, is best during low intensity, continuous effort training sessions because on a daily basis, the fluctuations in energy system contributions in the aerobic energy system is highly volatile.
Essentially, the pace or speed one needs to go to truly keep the body using low end aerobic energy can be influenced by acute factors such as recent hard efforts, inadequate recovery, dehydration, heat, humidity, or lack of fuel. Following the proper heart rate zones will make sure going at the right speed or pace for that day will truly be in the low end aerobic zones. Using pace or power for continuous aerobic efforts or recovery days will often lead to overworking, inadequate recovery, and ineffective low end aerobic energy system stimulation.
Using a runner as an example, if low end aerobic heart rate zone is prescribed at 150-160 beats per minute and one day the run pace is 6:30 min/mi for 45 minutes, two days later after a few volume-intensive or interval-intensive sessions the same aerobic zone heart rate zone run pace is only 8:00 min/mi for 45 minutes.
Why the difference?
Shouldn’t I just try to run the same pace for all my recovery or aerobic runs?
Shouldn’t I just push through and run my “easy” pace no matter what?
The answer is NO, quite the contrary. One may think if heart rate can be influenced by environmental or nutritional factors such as dehydration, how can it be indicative of aerobic energy contribution?
This is exactly why the use of heart rate monitors works optimally for low intensity continuous efforts. Heart rate can indicate the daily stress the body is managing and how hard the body is working, even if the velocity or power output is slower than normal. Even if it is 99 degrees and 100% humidity, the heart rate is the governor and barometer for low end aerobic output. Keeping within individualized heart rate zones will produce the intended physiological objective for the low end aerobic Systems and if you ignore heart rate for these types of sessions, you will not recover properly or improve aerobic efficiency. Letting paces, RPE or “feel” determine your training effort for these Systems will frequently lead to System shutdown, performance plateaus, performance decreases, and inefficient metabolic output.
On the contrary, pace not heart rate is best during intermittent, high intensity training. Use of heart rate during intermittent or interval training will not give an accurate indication of intensity or target specific energy system stimulation.
Specific velocities or power outputs along with appropriate volume and work to rest ratio are the best way to target upper end aerobic and anaerobic energy system stimulation. During intermittent exercise and high intensity interval training, an individual’s physiological make-up and the amount of work and rest will skew heart rate values in such a way that using heart rate as a governor for this type of training will not elicit a specific physiological response. Repeated use of heart rate for high intensity interval training will increase risk of injuries, negatively impact the metabolic system, and can cause metabolic inefficiency or weight gain.
The biochemical and physiological variables involved in energy system contribution during higher intensity training sessions are not influenced nor determined by heart rate response. Also, heart rate cannot indicate which system a person is training during intermittent moderate to high intensity training. If using heart rate as a guide to elicit a performance response in high intensity training, one is most likely not actually achieving the intended response. Increasing metabolic and performance outputs is achieved by proper stimulation of all energy systems and not just low end aerobic or high end anaerobic. Overstimulation of one energy system or training type, no matter which it is, will ultimately lead to injuries, metabolic shutdown, and performance declines.
The beauty of using heart rate in this manner is that heart rate is impartial to feelings or perception.
Although some days one may feel like the prescribed heart rate makes them go “too slow,” it’s what the body needs on that particular day. Adhering to proper heart rate zones will make greater performance gains in all energy systems and increase metabolic efficiency across. Going slow or easy some days will enhance your ability to go hard on others. Improving low end aerobic energy as well as high end intensive energy will make the body efficient at burning fuel, fats, and carbs, not only during exercise but also at rest. Metabolic efficiency will make fat melt away and improve performances.
Simply put, using heart rate properly in training will make one a lean, mean performance machine!
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