Zone 4 / Threshold Threshold workouts are focused on improving your FTP (functional threshold power) and strength at your LTHR (lactate threshold heart rate). This should be the goal of every endurance athlete. The working sets in this zone are done right at your threshold, slightly below (sub-threshold) or above (super-threshold, Joe Friel). Despite this, blood lactate does increase with exercise intensity, much like heart rate and RPE (rate of perceived exertion). Lactate is measured in mmol/l (millimoles per liter of blood). The amount of lactate in our blood at various intensities can help us build a picture of the metabolic efficiency of an athlete. Lactate Testing Did lactate threshold heart rate come from the watch? In which case that might well be the best one to use. So, use the zones that are derived from calculated values from the watch rather than estimated values. LTHR is defined as, well, the heart rate at which the lactate threshold is reached. The lactate threshold is an inflection point in intensity, right before blood lactate concentration starts increasing exponentially. This is why the most accurate test involves sampling blood and measuring Zone 3 is 80-90% of threshold heart rate. This is a long run type of effort. Breathing a bit harder here but I would say comfortable. Zone 4 is 90-100% of threshold heart rate. Harder intensity effort. You can reply in single word responses. Tempo type of run. Raising lactate threshold levels. Zone 5 is 100-110% of threshold heart rate. Tempo runs are the most popular session for increasing the lactate threshold and developing longer-term power and endurance. A good tempo session is at or just below threshold, i.e., your Zone 4 Heart Rate, where you can sustain the pace for a good amount of time (at least 10-20 minutes) and increase incrementally throughout your workouts. .

what is lactate threshold heart rate