Measuring Pulse or Heart Rate
The heart, acting as a pump, pushes blood through the circulatory system in a repeated cycle. Each heart beat starts the cycle of blood flow through the series of arteries, veins and capillaries. When the heart muscle contracts, or beats, it creates a high pressure pulse of blood into the arteries. This contraction is called the systolic phase of the heart beat. Since the arteries are elastic in nature, this high pressure pulse can be seen as an expanding of the arterial walls. When the blood pressure subsides between beats, the arterial walls go back to their original size. This low blood pressure is called the diastolic phase of the heart beat. This change from high blood pressure to low blood pressure, or the corresponding expansion and contraction of the artery walls, can be felt through palpation of an artery.
The pulse or heart rate can be easily measured without the need for any special equipment. All you need are two fingers, a clock or watch with a second hand and a palpable artery. Not all arteries are palpable. The artery must be close to the surface of the skin so you can feel it. You must also be able to press the artery up against a bone to keep it from moving away from your fingers. Arteries suitable for taking a pulse include the coratid artery (neck), radial artery (wrist), popliteal artery (behind the knee), brachial arterial (inside of the elbow) and posterior tibial artery (near the ankle joint).
To measure a pulse rate, place your index and middle fingers on back of the wrist, slightly towards the thumb side. You should be able to feel the blood pulsing through the artery as it expands and contracts. The easiest way to calculate the pulse rate is to count the pulse for 15 seconds, and then multiply that number by 4. This gives you the heart rate in Beats per Minute.
A healthy adult's resting pulse rate can range from 60 to 100 beats per minute. Pulse rates are usually higher in infants and young children. Athletes with strong physical conditioning may have a resting pulse rate lower than 60 BPM. A person's pulse rate is not constant. During sleep, the pulse rate can drop to as low as 40 BPM. During strenuous exercise, the pulse rate can rise as high as 150 to 200 BPM.