The body matters are converted into calories to determine the energy reserve. This analysis allows to monitor a patient’s energy capacity during a diet and to know if the person has followed accurately the food plan.
THE PHASE ANGLE (PhA) and THE IMPEDANCE REPORT (IR)
The phase angle gives information on the resistance of the cell membrane to the electric current.
A decrease of the resistance of the cell leads to a decrease of the phase angle.
It is increasingly used in undernutrition and for people with serious illnesses(Cancer . . . ) because it is also a predictor of mortality risk.
It is also a predictor of mortality risk. For more information, we recommend that you read this publication: KYLE, Ursula G. , GENTON GRAF, Laurence, PICHARD, Claude. Low phase angle determined by bioelectrical impedance analysis is associated with malnutrition and nutritional risk at hospital admission. Clinical Nutrition, 2013, vol. 32, no. 2, p. 294-299.
The studies give us only average results, but converge to admit that we enter a critical threshold (Cut off) if the Phase is below 4. 6 for women and 5 for men.
Apart from the Cut off above, it is difficult to give a precise reference value for each individual, as its phase depends on too many parameters (sex, but also size, muscle mass, active cell mass, activity level . . . ). This is why, unlike our other indicators, we do not give a reference value for a particular individual. However, with a little experience, one can fairly quickly identify whether the phase angle is high or low in relation to the person's profile.
General:
The taller, more muscular and younger people are, the higher the phase angle.
The phase in women is lower than in men because their active cell mass is proportionally lower, which of course does not mean that they are in poorer health.
Athletes who have developed a large muscle mass, will therefore have a higher phase than a standard individual of the same size, this does not mean that the individual as well as the standard individual is not in good health.
However, on the same individual, a decrease in phase angle will correspond to a decrease in cell reactivity and/or active cell mass.
For the follow-up of high level athletes it is also an interesting tool for monitoring their physical condition and for evaluations in extreme environments or before a competition.
The phase angle as an indicator of fitness and health
Some examples of results of people around 30, average height around 163 cm for women and 173 cm for men :
- Women with low to medium physical activity:
Phase angle should be between 5,5 and 6,5.
- Women with high physical activity or sport:
Phase angle should be between 6,5 and 8.
- Men w
ith low to medium physical activity or sport:
Phase angle should be between 6 and 7,5.
-
Men with high physical activity or sport:
Phase angle should be between 7 and 9.
For short people, the phase angle is a little lower and for tall people it is a little higher, which can exceed 10° in some very tall male athletes with highly developed muscles. The taller, more muscular and younger people are, the higher the phase angle.
From the age of 60 to 70 year, the phase angle tends to decrease and very old people naturally have a very low PhA (for example, for a woman of about 100 years old, it can go down to 3 without suffering from a serious disease other than ageing and cell depletion).
Phase angle as Cut off from risk of serious disease
– Women: 4. 6 - Men: 5
Follow-up in the history of the phase angle
The phase angle generally varies little (+/;- 0. 2 °) between 2 measurements:
- If it decreases in a punctual way, it may correspond to a punctual decrease in shape and/or a punctual health problem.
- If it drops significantly and/or regularly it may be due to a more serious cause. In the latter case, it will be important to take regular measurements every week or every two weeks, and if the phase angle continues to decrease regularly (history), it is advisable to carry out additional tests prescribed by a health professional.
The phase angle as "confidence index" of the measurement
If the phase angle is extremely low (2° below the minimum values indicated) or extremely high (2° above the maximum values indicated) in relation to the profile of the person, it may be a case of poor contact at the electrodes. In these cases, we recommend that you carry out a control measurement.
Some examples of correct measurements
Female 45 years old very small (149 cm)
Result above 5° but OK because very small size and female sex
Female 28 years old large (175 cm) but low activity level
Result OK because low activity, female sex and phase angle above 5°
Female 27 years old (163 cm) medium activity level
Result OK
Female 32 years old (163 cm) high activity level
Result OK
Female 26 years old (176 cm) high level sport
Result OK above 8 but large size and especially high activity level
Female 100 years old (147 cm) very low activity
Result OK because very old with low cell mass
Female in her forties (163 cm) with a malignant tumour
Result OK because in the prime of life and of medium size
Some examples of incorrect measurements
52-year-old woman (152 cm) low activity
Incoherent result because of small size, low activity and phase angle much greater than 6. 5°
63-year-old woman (165 cm) medium activity
Incoherent result because significantly greater than 6. 5
The impédance Report
(IR)
Concerning the IR (impedance ratio
)
The bioelectrical impedance ratio is the relationship between impedance measurements at high and low frequencies (200/5 kHz). The result is mainly a representation of excellent, normal or abnormal fluid and electrolyte distribution.
For example, citation in the publication « Abnormal Fluid Distribution and Low Handgrip Strength Index as Predictors of Mortality in Mexican Patients with Chronic Heart Failure »*:
« We included 546 hospitalized patients with stable heart failure (53. 3% men ) in a prospective observational study. The presence of an abnormal liquid distribution was determined with a bioelectrical impedance ratio (200/5 kHz) ≥0,85. » « impedance index can be a reliable and effective approach to detect fluid movement from intracellular to extracellular compartments independent of changes in body weight. »
One of the advantages of IR over PhA is that it is not influenced by a person's height, weight or level of muscle mass, allowing stable reference values to be established. There are only a few publications on IR, as it has only recently become apparent that IR can be an extremely interesting marker.
The few studies that we have at our disposal converge towards the interest that can be drawn from this simple data to obtain from Biody Xpert, both in many diseases (heart and kidney failure, lymphedema, gastrointestinal, cancer, inflammation . . . ), as well as in sports.
What we found after statistical analysis of measurements made with Biody Xpert :
- For the women around forty and with an average height, the IR is generally between 0. 750 and 0. 810 , but more generally between 0. 770 and 0. 800
-
For the men around forty and with an average height , the IR is generally between 0. 730 and 0. 800, but more generally between 0. 760 and 0. 790
-Athletes and/or people with a healthy lifestyle and good physical activity are in the lower ranges (0. 730 and 0. 770 , which is probably a way of monitoring their physical condition.
- The higher the IR is above 0. 820, the more people with a risk of pathology with a cut-off from 0. 840 corresponding to people with a pathology, which corresponds to published data.
- As we get older (from 60 to 70 years of age, depending on the case, and earlier in women than in men), IR tends to increase, particularly in women. The reason for this should be explained in further studies.
- Beyond a certain age (85 to 100 years) the IR readings that we currently have are very high and can exceed 0. 900 to 100 years. We do not yet have enough measurements of people of this age to validate this information, but it already seems credible. The reason for this should be explained in further studies.
Publications you can consult :
*Abnormal Fluid Distribution and Low Handgrip Strength Index as Predictors of Mortality in Mexican Patients with Chronic Heart Failure
Lilia Castillo-Mart´ınez PhD , Wendy D Rodr´ıguez-Garc´ıa PhD ,
Dulce G Gonz´ alez-Islas PhD , Arturo Orea-Tejeda MD ,
Mariel Lozada-Mellado MSc , Juan Rodr´ıguez Silverio PhD, Juan Gerardo Reyes-Garc´ıa PhD / PII: S0899-9007(19)30258-8 : DOI:
https://doi.org/10.1016/j.nut.2019.110699 Reference: NUT 110699 Accepted date: 26 November 2019
Impact of oedema on recovery after major abdominal surgery and potential value of multifrequency bioimpedance measurements
E. Itobi1, M. Stroud2 and M Elia2 Department of Surgery and 2Institute of Human Nutrition, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK
Phase angle and impedance ratio: Two specular ways to analyze body composition
Emanuele Rinninella1*; Marco Cintoni1; Giovanni Addolorato2; Silvia Triarico3; Antonio Ruggiero3; Alessia Perna4; Gabriella Silvestri4; Antonio Gasbarrini2; Maria Cristina Mele1
1- Clinical Nutrition, Gastroenterology Area, Catholic University of the Sacred Heart, Italy
2- Department of Internal Medicine and Gastroenterology, Catholic University of the Sacred Heart, Italy
3- Pediatric Oncology Unit, Catholic University of the Sacred Heart, Italy
4- Department of Neurology, Catholic University of the Sacred Heart, Italy
Tissue electrical properties measured by bioelectrical impedance analysis among healthy and sportsmen population
Dominik Kapica1, Joanna Warchulińska2, Monika Jakubiak2, Mariusz Teter2, Radosław Mlak2,
Magdalena Hałabiś3, Waldemar Wójcik1, Teresa Małecka-Massalska2 1Lublin University of Technology, Lublin, Poland; 2Department of Physiology, Medical University of Lublin, Lublin, Poland; 3Department of Laboratory Diagnostics, Medical University of Lublin, Poland
Correlation between PhA and IR
Below are some examples of women oncology staff
Warning : PhA cut-off: 4. 6 minimum value and IR cut-off 0. 840 maximum value
Example 1 of results on women subjects with advanced cancer whose PhA is below its cut-off and whose IR is above its cut-off :
PhA 3,2 – IR 0,857 / PhA 3,7 - IR 0,883 / PhA 4 - IR 0,879 -/ PhA 4,4 – IR 0,850 / -PhA 4,5 – IR 0,870
Example 2 of results on women subjects in oncology departments whose PhA above her cut-off and IR above her cut-off:
PhA 4,6 – IR 0,854 / PhA 4,7 - IR 0,854 / PhA 4,8 - IR 0,849 -/ PhA 4,9 – IR 0,845 / -PhA 5 – IR 0,847
Example 3 of results on women subjects in oncology departments whose PhA is above her cut-off and IR is below her cut-off:
PhA 5,1 – IR 0,830 / PhA 5,2 - IR 0,829 / PhA 5,3 - IR 0,823 -/ PhA 5,4 – IR 0,819 / -PhA 5,5 – IR 0,825
Conclusion: the lower the PhA, the higher the IR, but one can have a high IR even with a PhA above its cut-off.
The two data are therefore well complementary between the state of cell mass, fluid distribution and inflammatory state.
Example of correlation between phase angle and impedance ratio on more than 800 measurements performed with Biody Xpert on a population of women subjects in an oncology department.