Simple Pulse Qualities: Rate
Here we see that the slow pulse is due to a deficiency of pulse power as manifest in its rate rather than strength. So, a slow pulse is either a deficiency of yang (or qi) or an obstruction to the free-flow of yang, usually that would be internal excess cold.
How would you know if a slow pulse is due to excess cold or a yang deficiency? A forceful pulse suggests excess, a forceless suggests deficiency.
The fast pulse is indicative of excessive yang, which can be a relative excess of yang due to yin deficiency, or a yang pathogenic factor such as heat.
Remember, the fast pulse due to excess (heat likely) is going to be forceful, while fast pulse due to deficiency (of yin, blood, or sometimes qi) will be thin and/or forceless.
In the graphic below, we describe the slow and fast pulses as beats per (the practitioner’s) breath. This method of timing the pulse rate is a popular classical approach, however I believe that a watch with a sweep second hand is more accurate and simply easier to work with. “Beats per minute” are addressed on the page that explores pulse rate indications in more detail.
Next: pulse rhythm.