Introduction

• • HS-LS1-3 Plan and conduct an investigation to provide evidence that feedback mechanisms maintain homeostasis. [Clarification Statement: Examples of investigations could include heart rate response to exercise, stomate response to moisture and temperature, and root development in response to water levels.] [Assessment Boundary: Assessment does not include the cellular processes involved in the feedback mechanism.

Measuring Heart Rate

Traditional Technique - A normal resting heart rate ranges from 60 to 100 beats a minute for adults. For a well-trained athlete, a normal resting heart rate may be closer to 40 beats a minute. For healthy adults, a lower resting heart rate generally implies more efficient heart function and better cardiovascular fitness. With your palm facing upward, place two fingers on the thumb side of your wrist — or place your index and third fingers on your neck to the side of your windpipe. When you feel your pulse, count the number of beats in 20 seconds. Multiply this number by 3 to determine how many times your heart beats in one minute.

Phone App - Download and use Heart Rate. To measure the heart rate, the subject needs to press their skin onto the unit in a way that avoids ambient light leaking. The LED is then emitting light onto the skin, while the sensor is searching for a rhythm of color changes in the feedback he receives which can be used to determine your pulse.

Recovery Time

The amount of time the heart takes to return to a normal at-rest rate after exercise is called recovery time. This is one measure of the body's general fitness. In general, the shorter the recovery time, the higher the level of fitness. Determine recovery rate by first measuring and recording the pulse rate at rest. Next, run in place for two minutes. Now measure the pulse rate repeatedly until the at-rest rate is reached. How long did it take the heart to return to the normal rate?

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Exercise Target Heart Rate

You maximize the benefits of cardiovascular activity when you exercise in the zone of your target heart rate (THR). In general terms, your THR is 50-85% of your maximum heart rate. The Karvonen Method of calculating THR is one of the most effective methods to determine target heart rate because it takes into account resting heart rate. Here's how to find your THR.