Bioelectrical Impedance Analysis and Vasoconstriction

1. Bioelectrical Impedance Analysis and Vasoconstriction Taylor Guffey Lauren Morgan Harry Han Shelby Hassberger Daniel Kim Elizabeth Morris Rachel Patel RaduReit

2. Problem Statement & Purpose • Develop a hypothesis in which we test a factor, other than misuse and malfunction, that affects the analysis of body fat percentage. • The purpose of this study is to evaluate whether the temperature of the room can affect the body fat percentage reading for an individual.

3. Hypothesis Groundwork • Buono study finds ambient air temperature affects BF% reading • 20°C difference1 • Why air temperature? • Deghan study concludes vasodilation decreases BF% reading2 • Increase in skin temperature • Therefore, vasoconstriction increases BF% reading • Decrease in ambient air temperature to decrease skin temperature

4. Hypothesis Null Hypothesis • There will be no difference in the readings of body fat percentage from 24oC to 4oC as measured by the bioelectrical impedance analysis. Alternative Hypothesis • There will be a statistically significant increase in body fat percentage readings from 24oC to 4oC as measured by the bioelectrical impedance analysis.

5. Pilot Study • Follows trend suggested by Deghan

6. Sample Size • Sample size derived from pilot study • 23 estimated for statistical significance • 24 used in experiment • Error with input of subject A1 data

7. Materials/Methodology • 2 groups, 12 subjects each • 24°C hot room (PBL room in Whitaker) • BIA readings=Control • Space heater to maintain hot room temperature • 4°C cold room (in IBB) • Thermometerused to monitor room temperature • Read and sign consent form • Given Instruction sheet • Assigned alphanumeric ID on name tag • Given Data card with corresponding ID • Offered a jacket for experiment (both rooms)

8. Materials/Methodology • Clock to record time of subject’s entry • Height taken with meter stick • Weight taken with spring scale • Survey given to determine ineligible subjects • Omron HBF-360 Fat Analyzer to measure body fat % of subject http://image3.examiner.com/images/blog/wysiwyg/image/omron_HBF-306.jpg

9. Methodology • Two groups • A1-12 and B1-12 • Time limited to 3 hours • 38 minutes per trial • 2 trials • Subjects enter hot room 30 seconds apart • Last 2 subjects enter 1 minutes apart

10. Simulation Waiting Area Door Heater Height Ten Minutes Later Ten Minutes Later Waiting Area Survey & Time Table Chair Time & BIA Reading Station Weight BIA Reading Station Door Warm Room 24oC Cold Room 4oC

11. Data

12. T-Score Calculation XD = Mean of the differences SD = Standard Deviation of the differences n = Sample size μ0=Population mean

13. Statistical Analysis • Student’s Matched-Paired One-Tailed T-test • Null Hypothesis is rejected • p < .05

14. Analysis 1.237

15. Outliers Q1 Q2 Q3

16. Discussion • Null hypothesis is rejected • Statistically significant increase in BIA readings • Average increase in BF% reading by 1.237% • Data supports the alternative hypothesis

17. Improvements • Smaller sample size • Small p-value • Multiple devices per room • (same device used on subject throughout)

18. References 1Buono, M. J., Burke, S., Endemann, S., Graham, H., Gressard, C., Griswold, L., et al. (2004). The effect of ambient air temperature on whole-body bioelectrical impedance. Physiological Measurement, 25(1), 119-123. 2Dehghan, M., & Merchant, A. (2008). Is bioelectrical impedance accurate for use in large epidemiological studies? Nutrition Journal, 7(1), 26.

19. Questions?