As fitness wearables like the Apple watch, FitBit, and Garmin are getting more and more popular, tracking your heart rate is becoming a hot topic. I believe there are far more effective (and easier) ways to measure the quality of your workout and recovery, but I wanted to touch briefly on the topic today before finishing out this week on common excuses.

Regarding this topic, I frequently come into contact with people afraid of getting their heart rate too high. Unless your primary physician has counseled you otherwise, I contest that your heart rate should never be a concern when exercising.

Fitness

One way you could define fitness is the range from your resting heart rate to your maximum heart rate. The ability you’re able to go from a low, slow heart rate during the day to a high, fast heart rate is an amazing sign of your health, specifically your (autonomic) nervous system. In other words, we want to be able to do more with fewer heart beats.

Resting Heart Rate: Your resting heart rate (RHR) is measured best when you’re asleep. The healthiest individuals in the world have vampire-like RHR around 40 beats per minute. This measurement is an indication of how responsive your body is to the parasympathetic nervous system (controls organs, digesting food, growing hair and fingernails, etc.)

Maximum Heart Rate: Your max heart rate declines with age. In general, your max heart rate is 220 beats per minute minus your age (i.e. if I’m 42 years old, my max heart rate would be approximately 178 beats per minute). The healthiest individuals vary their exercise based on percentages of their max heart rate. This measurement is an indication of how responsive your body is to the sympathetic nervous system (think anything that would cause you to “fight or flight”).

Heart Rate Zones

Many collegiate coaches will program workouts for their athletes in “zones.” They can be outlined like this:

Zone 1: 50% – 60% of max heart rate. This includes something like walking up an incline or biking to work. The main benefit here is recovery. If you’re really sore, going on a hike or riding around on your bike with your family is a great way to feel more recovered.

Zone 2: 60% – 70% of max heart rate. This is the pace you would run a marathon at. It’s not as comfortable as zone 1, but you should be able to go for a long time. Zone 2 improves your overall endurance.

Zone 3: 70% – 80% of max heart rate. This includes something like running a 5k. You’re probably not going to wake up the next day sore from your workout, but you should be pretty tired after this. Zone 3 improves blood circulation in heart and skeletal muscles as well as your stamina.

Zone 4: 80% – 90% of max heart rate. This includes something between a 400-meter and 1-mile run and is where soreness kicks in the next day. Think of workouts like “Fran” or “Diane” if you do CrossFit (anything between 1-minute and 5-minutes). You’re moving away from aerobic and into anaerobic exercise where the bulk of your energy is generated from the glycolytic pathway. Your speed will improve in zone 4.

Zone 5: 90% – 100% of max heart rate. This includes a max-effort sprint between 40-meters and 200-meters. I contest that the vast majority of the general exercising public has never experienced this zone. After a true max-effort attempt, your energy levels are totally depleted. Anything between 3-seconds to 20-seconds falls here. You’re now generating your energy from the phospocreatine pathway and will improve things like power output.

What’s fascinating is that training in Zones 4 and 5 actually reap the same benefits as Zones 2 and 3. However, training in Zones 2 and 3 will not reap any of the benefits that Zones 4 and 5 will.

Takeaway

Fitness can be measured by your heart rate range — how low and then how high can your heart rate go. This is also a measurement of how responsive your body is to the nervous system (also known as “heart rate variability”).

You shouldn’t find yourself working out in the same zones every day. What we say at RxFIT is that routine is the enemy. We seek variation in our workouts because the body becomes increasingly resistant to an incessant stimulus.

For example, in two weeks Zach Jarvis and Darren Hodges will be maxing out their back squat and deadlift, then will be performing a half-ironman. They will squat over 400-lbs, deadlift over 500-lbs, and then average an 8-minute mile on the run after swimming and biking close to one hundred miles – an impressive demonstration of power, speed, stamina, and endurance.

This test of fitness covers the whole spectrum of heart-rate zones.

Tyler

P.S. If you were to bias your training, I would recommend zones 4 and 5 over the others because you will reap most of the same benefits as the other zones. But in general, strive for variance in your cross training.