ABSTRACT
The heart rate diminishes by 10-20 bpm during sleep (Herbert and Alison 1996).
An abnormally slow pulse is termed bradycardia; in an adult this would usually
be a pulse rate below 60 bpm. An abnormally fast pulse is termed tachycardia –
usually a pulse rate above 100 bpm in an adult. There are many reasons for a fast
pulse – for example, a fever, an overactive thyroid gland, and certain drugs speed
up the pulse. An underactive thyroid gland, hypothermia and some drugs slow
the pulse. The thickness and tension of a patient’s arteriole walls influences the
pulse. Atherosclerosis develops in many people over the age of 40 years and can
lead to structural changes in the arteries, thus altering the pulse rate.