<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Athletes need a balanced body composition in order to achieve maximum performance. Especially dehydration reduces power and endurance during physical exercise. Monitoring the body composition, with a focus on body fluid, may help to avoid reduction in performance and other health problems. For this, a potential measurement method is bioimpedance spectroscopy (BIS). BIS is a simple, non-invasive measurement method that allows to determine different body compartments (body fluid, fat, fat-free mass). However, because many physiological changes occur during physical exercise that can influence impedance measurements and distort results, it cannot be assumed that the BIS data are related to body fluid loss alone. To confirm that BIS can detect body fluid loss due to physical exercise, finite element (FE) simulations were done. Besides impedance, also the current density contribution during a BIS measurement was modeled to evaluate the influence of certain tissues on BIS measurements. Simulations were done using CST EM Studio (Computer Simulation Technology, Germany) and the Visible Human Data Set (National Library of Medicine, USA). In addition to the simulations, BIS measurements were also made on athletes. Comparison between the measured bioimpedance data and simulation data, as well as body weight loss during sport, indicates that BIS measurements are sensitive enough to monitor body fluid loss during physical exercise.</p></abstract>

Athletes need a balanced body composition in order to achieve maximum performance. Especially dehydration reduces power and endurance during physical exercise. Monitoring the body composition, with a focus on body fluid, may help to avoid reduction in performance and other health problems. For this, a potential measurement method is bioimpedance spectroscopy (BIS). BIS is a simple, non-invasive measurement method that allows to determine different body compartments (body fluid, fat, fat-free mass). However, because many physiological changes occur during physical exercise that can influence impedance measurements and distort results, it cannot be assumed that the BIS data are related to body fluid loss alone. To confirm that BIS can detect body fluid loss due to physical exercise, finite element (FE) simulations were done. Besides impedance, also the current density contribution during a BIS measurement was modeled to evaluate the influence of certain tissues on BIS measurements. Simulations were done using CST EM Studio (Computer Simulation Technology, Germany) and the Visible Human Data Set (National Library of Medicine, USA). In addition to the simulations, BIS measurements were also made on athletes. Comparison between the measured bioimpedance data and simulation data, as well as body weight loss during sport, indicates that BIS measurements are sensitive enough to monitor body fluid loss during physical exercise.

Monitoring Change of Body Fluid during Physical Exercise using Bioimpedance Spectroscopy and Finite Element Simulations

Journal of Electrical Bioimpedance

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Athletes need a balanced body composition in order to achieve maximum performance. Especially dehydration reduces power and endurance during physical exercise....

	σ [S/m]	ε_r
Skin	0.065836	15357
Bone	0.020791	227.64
Fat	0.024414	92.885
Muscle	0.36185	8089.2

Subjects	Parameter
	ΔR_e,rel [%]	ΔR_e,AA [%]	ΔWeight [%]
1	5.2	3.4	-2.3
2	2.8	1.9	-3.0
3	1.7	0.2	-3.3
4	0.5	1.4	-2.2
5	4.0	0.24	-2.3
6	4.21	–	-1.2
7	2.22	–	-1.5
8	2.59	–	-1.3
9	4.94	–	-0.8
10	2.46	–	-1.3

Athlete’s ID no.	Age (years)	Height (m)	Weight (kg)	Sex
1	27	1.99	101.4	Male
2	22	1.89	75.5	Male
3	27	1.78	60.8	Male
4	31	1.71	81.5	Male
5	34	1.70	76.9	Male
6	26	1.70	69.3	Female
7	25	1.77	71.8	Female
8	25	1.89	75.6	Male
9	25	1.78	80.7	Male
10	25	1.71	74.9	Male

Tissue/Cutting Plane	Thigh	Knee	Lower Leg
Bone	0.1 %	2.07 %	0.27 %
Muscle	96.05 %	84.82 %	98.95 %
Fat	3.86 %	13.12 %	0.77 %

Monitoring Change of Body Fluid during Physical Exercise using Bioimpedance Spectroscopy and Finite Element Simulations

Article Category: Articles

Published Online: Dec 07, 2011

Page range: 79 - 85

Received: Jun 06, 2011

DOI: https://doi.org/10.5617/jeb.178

Keywords
Bioimpedance Spectroscopy, dehydration, FE simulation, physical exercise

© 2011 Lisa Röthlingshöfer, Mark Ulbrich, Sebastian Hahne, Steffen Leonhardt, published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6

Fig. 7

Permittivity and conductivity values at 100 kHz [27]

Change of Re and weight for all 10 athletes.

Physical data of the ten athletes.

Current density contribution (in percentage) at 1 MHz.

Monitoring Change of Body Fluid during Physical Exercise using Bioimpedance Spectroscopy and Finite Element Simulations

Article Category: Articles

Published Online: Dec 07, 2011

Page range: 79 - 85

Received: Jun 06, 2011

DOI: https://doi.org/10.5617/jeb.178

KeywordsBioimpedance Spectroscopy, dehydration, FE simulation, physical exercise

© 2011 Lisa Röthlingshöfer, Mark Ulbrich, Sebastian Hahne, Steffen Leonhardt, published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6

Fig. 7

Permittivity and conductivity values at 100 kHz [27]

Change of Re and weight for all 10 athletes.

Physical data of the ten athletes.

Current density contribution (in percentage) at 1 MHz.

Keywords
Bioimpedance Spectroscopy, dehydration, FE simulation, physical exercise