IB Biology Topic B3.2.4: Measurement of Pulse Rates Notes

Your Pulse Is a Direct Measure of Your Heart Rate

1. Every heartbeat sends a surge of blood through your arteries, creating a pressure wave that travels along the vessel walls.
2. Where arteries run close to the skin, such as the wrist or neck, you can feel this wave as a pulse.
3. Each pulse matches one heartbeat, so counting your pulse is a direct way to find your heart rate.

Manual Measurement: Finding Your Pulse by Hand

1. Radial pulse (wrist): use the radial artery on the thumb side of your wrist.
   1. Place two or three fingertips, not your thumb, lightly on the underside of your wrist just below the base of your thumb.
   2. Press gently until you feel the rhythmic beats.
   3. Count the beats for 30 seconds and multiply by two for beats per minute, or count a full minute for greater accuracy.
2. Carotid pulse (neck): use the carotid arteries on either side of your neck near the windpipe.
   1. Place two fingertips on the side of your neck, just below the jawline and to the side of the windpipe.
   2. Press lightly until you feel the pulse.
   3. Count the beats in the same way as the wrist method.

Digital Methods: Technology-Based Pulse Detection

1. Technology has made pulse measurement more convenient and precise.
2. Devices like pulse oximeters and fitness trackers monitor heart rate automatically.
3. Pulse oximeters
   1. These small clip-like devices attach to your fingertip.
   2. They use red and infrared light to measure changes in blood volume with each heartbeat and work out your pulse rate.
   3. They also measure blood oxygen saturation for a fuller picture of cardiovascular health.
4. Fitness trackers and smartwatches
   1. These wearables use optical sensors to measure your pulse through your wrist.
   2. They often give continuous monitoring and store data for long-term analysis.
   3. They are especially useful during activities like exercise or sleep, where manual counting is hard.

Comparing Traditional and Digital Methods: Accuracy, Cost, and Convenience