Quick heart rate zone refresher.
HR zone 1 or Z1 – 50 to 60% of max HR: this is the very low-intensity zone. Training at this intensity will boost your recovery and get you ready to train in the higher heart rate zones. We spend the first few minutes in Z1 before we begin a more focused warm-up.
HR zone 2 or Z2 – 60 to 70% of max HR: exercising in zone 2 feels light and you should be able to go on for a long time at this intensity. We were in this intensity for most of our workout on Tuesday, hopefully. This is the zone that improves your general endurance: your body will get better at oxidizing fat and your muscular fitness will increase along with your capillary density.
HR zone 3 or Z3 – 70 to 80% of max HR: as CrossFitters, we spend a tremendous amount of time in this zone. The key to this zone is during a workout which pushes and keeps you in Z3, all 3 energy systems will be tested. Working out in zone 3 is especially effective for improving the efficiency of blood circulation in the heart and skeletal muscles. Training in this HR zone will make moderate efforts easier and improve your efficiency in all zones.
HR zone 4 or Z4 – 80 to 90% of max HR: zone 4 is where the going gets tough. You’ll be breathing hard and working aerobically. If you train at this intensity, you’ll improve your speed endurance. Your body will get better at using carbohydrates for energy and you’ll be able to withstand higher levels of lactic acid in your blood for longer. Our shorter AMRAP’s, complex movements, and stringing reps together in longer workouts will push you into this zone. It is very difficult to sustain this zone, but dipping your toes into the pool of Z4 is how we really push ourselves.
HR zone 5 or Z5 – 90 to 100% of max HR: zone 5 is your maximal effort. Your heart and your blood and respiratory system will be working at their maximal capacity. Lactic acid will build up in your blood and after a few minutes, you won’t be able to continue at this intensity. 1 rep maxes, sometimes long barbell complexes, and any kind of sprints, especially on the death tricycle.