Part 1: Principles of Training using Heart Rate
(1) Heart Rate is Individualized.
I can give five athletes the same workout directed based on heart rate, and each athlete can have it feel different, even if they all have the same fitness level. This is because each athlete will have a different Max Heart Rate (which differs for many reasons, not limited to age), as well as resting heart rate.
For this reason, our athletes use Heart Rate Zones based on their max heart rate.
This allows for some consistency in RPE (rating of perceived exertion) or time to fatigue in different workout scenarios. Zone 1 might be 111-130bpm for one athlete and 123-144bpm for another, however they will both have similar exertion levels.
(2) Heart Rate Varies Based on Modality.
This also goes for cardiac output and stroke volume. In other words, your heart rate rowing will not be the same as on the Assault Bike. Running will be different than swimming. 20.1 will be different than 19.2.
This is due to (2.1) the muscle groups involved, (2.2) the Orientation of the body, (2.3) the athlete’s cardiac development, and (2.4) other factors like thermoregulation.
2.1 – Involved Muscle Groups
The larger the muscle groups are that power the movement, the higher the heart rate will be (ski erg < assault bike). The more total musculature involved the higher the heart rate (bike erg < running).
2.2 – Body Orientation
Horizontal activities (e.g. swimming, prone paddle, etc.) allow blood to return to the heart easier (not fighting gravity) so cardiac preload (end-diastolic volume) is higher, which increases stroke volume (amount of blood coming out of the heart in each beat). Typically, this is associated with lower heart rates. This is one reason why horizontal exercises like swimming usually have lower max heart rates than vertical exercises like running.
2.3 – Athlete Cardiac Development
The better cardiac output (heart development) an athlete has, the better they will be able to push blood through muscular tension generated by exercise. An athlete with great cardiac output will be able to continue to move blood through their quads during front squats at 95/65lbs while an athlete with poor cardiac output and high muscular tension, will occlude (stop) blood flow from (or to) the muscle. It’s like kinking a garden hose.
This is less relevant when talking about cyclical endurance activities, but with CrossFit athletes doing MetCons with a wide array of movement pairings and loading, this is very important and has complicated impacts on heart rate.
2.4 – Other Factors, Like Thermoregulation
Too often people look at heart rate as simply a factor of output, much like watts on the AirBike. If I can spin at 300 watts and stay in Zone 2 one day, I should be able to do it next week right?
While this is often true, heart rate is impacted by countless other factors besides your output. Some obvious factors include sleep, fatigue, hydration status, and HRV (heart rate variability). However, sometimes it’s things further out of your control, like climate.
If it’s summer, your heart doesn’t just have to pump blood to your working muscles, it also has to pump blood to the surface of your skin. You need blood to cool down (thanks to sweat evaporation) and return to your core and keep the core system within an acceptable range. In other words, when you’re overheating cardiac output will be much higher (at a given bodily output) than when you’re comfortable.
(3) Heart Rate is Best Used to Cap Output.
Practically, it is much easier to “Row 2k for Time,” than it is to “Get your Heart Rate in Zone 4 & Hold Maintain It for 6 Minutes” even though the output is likely the same.
There is something very challenging (and almost defeating) about writing super stressful heart rate work. Most athletes (myself included) would much rather focus on performance metrics (like rowing pace) once RPE climbs past a certain threshold.
For this reason, I mainly use heart rate as a means of limiting performance, effort and output. For example, “In this burpee / run piece I want you to keep your heart rate below Zone 3.” This encourages the athlete to focus moving with high efficiency and to place high intention on energy expenditure, rather just trying to “go hard.”
There are three frequent times I use this kind of cap.
First, I create hard caps on heart rate during recovery days. When the desired outcome is improved recovery, oxygenation and nervous system tone, keeping RPE low is key.
Second, is making sure easy aerobic work stays easy. Often athletes I work with want to do intense work, but intense work doesn’t always produce the desired outcome or adaptation.
Third, is progressive intervals where work starts moderate and builds to a certain threshold intensity before a period of rest or low work. For example, “Build your heart rate linearly across a 500m Row, ending with your heart rate in the bottom of Zone 4.”
I also like modulating rest times based on heart rate. “Rest until heart rate enters Zone 1.” This prevents athletes from going too soon before they are ready or resting too long and affecting their interval density.
Mistakes: Too often I see a coach have an athlete build (from rest) straight to 90%+ of their heart rate. The issue is, this could easily be RPE 9 or 9.5 out of 10 on a given modality, leaving the athlete useless for future sets. Or, their first set is double or triple (or more) the length of the rest of their sets.
The solution is allowing the athlete to build their heart rate slowly through a period of easier work prior to the onset of the first interval. Something to the tune of three to five minutes at a ramping pace will do the trick, then entering immediately into the desired training piece.
Heart Rate is Best for Longer Efforts: If you expect to regulate intensity in sprint or strength work, I would do so only during the rest periods. If you try to regulate intensity, reps, time during the high intensity period, you won’t get the desired effect. This is because of cardiac lag. Basically, heart rate takes some time to “catch up” to your muscular output. In a sprint, this is quite a big separation and therefore heart rate is a poor way to measure work in these environments.
It’s much better to use heart rate to monitor the rest time between sets of strength work or sprint intervals. “Rest until heart rate is consistently in Zone 0.”
The Heart Rate Monitor I Recommend.
Since I’ve gotten some emails about it, I wanted to include here my favorite heart rate monitor. I like Polar HR Monitors a lot for several reasons, including accuracy, but another main one is being they connect with my Assault Bike.
Part 2: Sample Training Protocols
#1: AirBike Energy Systems Training
Assault Bike, starting at 100 watts
-Every 30s: Climb by 50 watts
–Stop once you enter Zone 4
–Rest until 8 out of 10 recovery
*record top wattage for each set
*record rest times for each set
#2: AirBike Desaturation
Every 90s: 10s Assault Bike Sprint @ Max Effort
-Stop once you fail to return heart rate to Zone 2
(Rest 4:00 & Repeat)
*record number of completed sprints in both sets
#3: Run Energy System Training
Run 800m @ 5k Time Trial Pace
-Run @ Mile Time Trial Pace; until Fatigue Sets In
-Walk at recovery pace until Zone 1
*record total run mileage (including warm-up 800m)
Walk 10:00 with Breath Sync
-4 Step Inhale, 6-Step Exhale
#4: Row Aerobic Endurance
-Row @ 5k Time Trial Pace +3-5s, 32-34 SPM, 1:1 Breath Ratio, until Zone 3
-2:00 Assault Bike @ 50% of 10:00 Test Avg. Wattage, nasal breathing only
*record total meters completed on rower
#5: Back Squat Strength Work
Back Squat (5×5) @82-84% 1RM
-Rest until Heart Rate returns to middle of Zone 0
*record load used & RPE
#6: Recovery Day Programming
30:00 @Zone 0 Heart Rate
-12 Palov Press / side
-30s Goblet Squat Hold
-30s FLR Hold
-30s Dead Hang from the Pull-Up Bar
#7: Aerobic Accumulation
30-90 Minutes: Ruck, Bike, Hike, Paddle
-Get outside; hard cap at top of Zone 1
*record which modality you did
#8: Sustainable MetCon
-60 Double Unders
-12 Bar-Facing Burpees
-6 Power Snatch 115/85lbs
*complete this as if it were a 20 minute AMRAP
*if your heart rate ever enters Zone 4, move to singles on the Snatches
*records your score as rounds + reps
#9: EMOM Energy Systems Training
Odd: 30s Row @1600 Cals / Hr
Even: 15 Wall Balls; Unbroken
*if you fail to maintain row pace or are forced to break the wall balls, rest until heart rate re-enters Zone 2, then restart where you left off.
*note the number of breaks and their length
#10: Open 18.1 Flush Protocol
AMRAP 20:00 (TEST)
-10 Dumbbell Hang Power Clean & Jerk (5+5)
-14/10 Calorie Row
ASAP: Get on the AirBike
-Spin @ recovery pace until heart rate re-enters Zone 0 and stays there for 60s
(This should take between 5 & 15 Minutes)
Mobility as Needed