Activity 3C Part 3: Bioelectrical Impedance Analysis: What’s Your Resistance Topic: Obesity Part of: Unit: Corpulosity: A Study of Obesity

Entire Activity Download (35 pages - 7 MB)

Individual Downloads

• Teacher Background Information (2 MB)
• Teacher Administrative Information
• Teacher Answer Key
• Teacher Scenario Cards
• Student Part A Measuring Resistance in the Body (1 MB)
• Student Part B The Relationship between Resistance and Distance
  (1 MB)
• Student Part C Relationship between Resistance & Concentration of Ions (1 MB)
• Student Part D: The Relationship between Resistance and Water (1 MB)

Keywords

body composition, fat mass, fat-free mass, resistance, reactance, impedance, bioimpedance, fat content, electrical bioimpedance, body fat

Search Curricular Keywords

Key Concepts

bioimpedance, human body composition, BIA, BMI, impedance, resistivity, reactance, electrolytes, ions, hydration, dehydration

Process Skills Utilized

make a hypothesis, gathering data, organizing data in a chart form, analyzing data, draw conclusions, reading a scale on an instrument

Intended Grade Level - 6-8

Objectives

Using a multimeter and common materials, students will be able to:

• describe basic human body composition as fat mass and fat-free mass.
• apply terms such as resistance, reactance and impedance.
• explore how bioimpedance can be used to measures the fat content of humans.
• evaluate the effectiveness of electrical bioimpedance machines as an accurate measure of body fat in humans.
• collect, record, and analyze data.
• identify independent variables, dependent variables, and constants.

Activity Description

Part A Measuring Resistance in the Body
Students will use their knowledge of simple series circuits from prior activities and a multimeter to explore electrical resistance in the human body.

Part B The Relationship between Resistance and Distance
Students will measure how electrical resistance changes over distance in a human arm.

Part C Relationship between Resistance & Concentration of Ions
Students will explore how the concentration of a solution can change the electrical resistance of that solution. This will be related to the concept of dehydration and how bioelectrical impedance is dependent on the hydration levels in the human body.

Part D: The Relationship between Resistance and Water
Using scenario cards, students will analyze human conditions to determine how they affect the calculated percent of body fat in a human being.

Activity Materials (per group)

• 1 Student volunteer
• 1 Analog multimeter
• 1 Metric tape measure or ruler
• 1 Bottle of electrode gel [This gel can be made by mixing 40% volume baby shampoo with 60% volume water and add 5% weight of NaCl, table salt. See BME journal article.]
• 1 Container of baby wipes
• 1 Water-based marker
• 1 5 oz plastic bathroom cup
• 1 Graduated cylinder (250 ml)
• 1 1/2 tsp Measuring Spoon
• Distilled Water
• Bathroom Scale
• 1 Calculator
• 1 Set Scenario Cards – cut and laminated for reuse
• Salt [Kosher salt (from the supermarket) is preferable or even using Instant Ocean (salt from an aquarium store) over table salt (NaCl) which has a very low solubility. These other salts seem to dissolve much more readily in tap water.]
• 1 Copy Student Data Pages (per student)

Activity Management Suggestions

Students might investigate the availability of devices for the consumer which measure body fat through bioimpedance. They would then look at the pros and cons of that particular device by looking at the manuals for these devices which are usually found on the Internet in a pdf file.

There is a growing body of research and technology being developed that harnesses the electric charge of a human to transmit and send data. Student can research new developments in clothing and wireless devices that address this interest.

Students can keep a log of their BMI over time to see how it changes.

Activity References Used

Biggs, James, Cha, Kichul, & Horch, Kenneth (2001). Electrical resistivity of the upper arm and leg yields good estimates of whole body fat.Physiological Measurement. 22, 1-12.

Cornish, Bruce (2006). Bioimpedance Analysis: Scientific Background. Lymphatic Research and Biology. 4, Nov.1, 47-50.

Gallagher D, Heymsfield SB, Heo M, Jebb SA, Murgatroyd PR and Sakamoto Y. (2000). Healthy percentage body fat ranges: an approach for developing guidelines based on body mass index. Am J Clin Nutr 72:694-701.

Gonzalez-Correa, C A, Brown, B H, Smallwood, R H, Walker, D C, & Bardham, K D (2005). Electrical bioimpedance readings increase with higher pressure applied to the measuring probe. Physiological Measurement. 26, 839-847.

Kinney, K.R., Miller, E.J., Birkeneder, E.J., Valley, C.V., Muller, D, & Tyler,M (2003). Biofeedback and Stress Management. BME. 400, 1-18.

Kotler, D, Burasterp, S, Wang, J, & Pierson , R Jr. (1996). Predition of body cell mass, fat-free mass, and total body water with bioelectrical impedance analysis: effects of race, sex, and disease. American Journal of Clinical Nutrition, 64 (supplement), 489S-497S.

Heymsfield, Steve, Lohman, Timothy, Mian, Wang & Going Scott (2005). Human Body Composition. Champaign, IL: Human Kinetics.

Rees, A.E., Ward, L.C., Cornish, B.H., & Thomas, B. J. (1999). Sensitivity of multiple frequency bioelectrical impedance analysis to changes in ion status. Physiological Measurement, 20, 349-362.

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