Basic training rhythm, the least intense: heart rate below 75% - 80% of anaerobic threshold heart rate (or lower than 70% - 75% of maximum heart rate).; heart rate between 110 and 130 per minute; breathing is relatively normal and effort perception lies between 2-3 on a scale of 1 to 10. Intensity used to connect work between different trainings, also chosen when the chart has no specific indications (if only duration is written, exit has to be done at a slow rhythm). Every training session should start with at least 15-20 minutes at this level before moving on to other specific tools listed in the chart (e.g. fast, medium, or threshold …).