For decades, various clinical problems for the elderly have attracted attention [1]. Among them, sarcopenia, frailty and locomotive syndrome are crucial matters for diagnosis and treatment in the rehabilitation medicine [2]. Such people often have health problems of QOL, ADL and life style-related diseases [3]. Further, several impaired function of physical performance and muscle factors will be emerged [4]. Then, functional performance would be evaluated from clinical points of view [5]. Several reviews presented certain correlations among frailty, sarcopenia, and muscle analyses [6].

When evaluating sarcopenia, recent measures have included several methods including CAT scan, MRI/MRA, bioelectrical impedance analyses (BIA) and dual energy x-ray absorptiometry (DXA) [7]. By applying BIA, we can obtain important markers such as total body water (TBW), extracellular water (ECW), ECW/TBW ratio and phase angle (PhA) [8]. Authors have investigated several research for BIA and reported the novel findings for the elderly people [9]. Especially for the elderly people, increased ECW/TBW and decreased PhA seemed to be rather prevalent [10]. They are probably from slight edematous situation and less function level of human organ cells [11]. During our clinical research so far, we happened to experience impressive cases, where compared study would be described with certain perspectives in this article.

In this study, applicants include 2 males who received the detail examinations of BIA. Case 1 is 68-year-old male who is a medical staff in the hospital and has been healthy without remarkable diseases so far. He likes sports, and played baseball and athletics for years. Case 2 is 77-year-old male who has been treated as type 2 diabetes (T2D) for years. Recent HbA1c has been stable about 6.2% to 6.5%. He likes to play golf, to practice golf about twice per week, and to go to golf-field 1-2 times a month. Both cases have the same height of 165 cm, and almost same weight as 59.5kg vs. 59.4kg. The BMI value was 21.85 vs. 21.81, respectively.

For current investigation, various biomarkers were measured and calculated by novel BIA method. It was InBody that was developed in Japanese medical company [12]. The precise analysis was from the principle of BIA [13]. It has been a useful instrument of presuming human body composition including PhA, TBW, ECW, and ECW/TBW ratio and others [7]. Actually, clinical measurement of BIA has taken a few minutes with convenient and simple method. The data can be obtained when the applicant is standing or sitting position. In the light of fundamental medical and electrical information, the related equation has been important. They use three factors as Z: impedance, Rz: resistance, Xc: reactance, and the impedance is defined for Z = (R² + X²)^1/2, which means equivalent of the diagonal line.

Both cases have the same stature (165cm), and almost same body weight (59.5kg vs. 59.4kg) and BMI. However, apparent difference

would be found for 47.4kg vs. 36.6kg as soft lean mass (SLM), and 9.3kg vs. 20.7kg as fat, and 15.6% vs. 34.9% as body fat ratio (Table 1).

Table 1: The results of InBody in case 1 and 2.

Concerning segmental lean analysis, apparent differences were found (Table 2). Case 1 showed left arm 94.2%, trunk 94.5% and left leg 105.9%, and case 2 showed left arm 69.7 %, trunk 79.6% and leg 89.2%. These results revealed remarkable difference. As to ECW/TBW, case 1 showed less than 0.37 in 4/5 portions, and case 2 showed more than 0.390 in 3/5 portions, and more than 0.400 in 2/5. Large difference of ECW/TBW was found between the cases.

Both cases showed significant difference of skeletal muscle mass index (SMI) for 8.0 vs. 6.5 kg/m², respectively (Table 3). As to water metabolism, Intracellular water (ICW) plus ECW equals to TBW. Then, ECW/TBW can be calculated as 13.5/26.8 for case 1, and11.5/28.7 for case 2. Regarding whole body PhA, remarkable difference was observed as 7.8 vs. 4.7. It shows the different of generally physiological function degree. As segmental body PhA, case 2 showed remarkably lower results in right leg as value of 0.5.

Table 2: The results of lean analysis and ECW/TBW.

Table 3: The results of SMI and phase angle (PA).

By the recent BIA measurements, several biomarkers have been clarified including TBW, ICW plus ECW, ECW/TBW ratio, skeletal muscle mass (SMM), SLM, body fat mass (BFM) and fat free mass (FFM). Further, PhA has been obtained as the device of reactance (Xc) and resistance (R) at 50 kHz [14]. For this study, the ECW/TBW data obtained for Case 1 (age 68) and Case 2 (age 77) were 0.368 and 0.399, respectively. Regarding these data, we have previously statistical data on ECW/TBW from people in their 20s to 80s. Looking at the average values in the middle of that data (n=384), in 10-year increments, it is 0.3842 for men in their 60s and 0.3892 for men in their 70s. Another calculation method is y=0.00027x + 0.3675 as a provisional regression curve for men in their 20s to 80s, which was calculated from our unpublished data (n=384). Calculating from this, the standard value for a 68-year-old is 0.3856, and the standard value for a 77-year-old is 0.3883.

The authors’ et al have previously reported a study related to BIA [9]. The subjects were female elderly (n=73, 77.6 years in average), and they were divided into 2 groups by ECW/TBW (<0.40 vs. >=0.40). For medical history, significant difference was observed in hypertension (31.5% vs. 57.9% p=0.042) and sarcopenia (14.8% vs. 42.1%, p=0.019). On the other hand, there were no significant differences in diabetes, dyslipidemia, heart disease, and cerebrovascular accident (CVA). When comparing results of biomarkers, significant differences were found in grip strength (21.3 kg vs. 17.6 kg, p=0.004), walking speed (1.2 m/s vs. 1.0 m/s, p=0.002), and ECW/TBW (0.392 vs. 0.404, p< 0.001). In contrast, no significant difference was observed in SMI. Regarding the correlation between SMI and grip strength, a correlation was observed in the former group, but not in the latter group.

As to ECW/TBW, case 2 showed elevated values, especially > 0.400 in the legs. Actually, case 2 complained of pretibial edema (PTE) in bilateral lower legs. The average of ECW/TBW showed 0.368 vs. 0.399 as case 1 vs. 2, which suggested the large difference of cell function in two applicants. When ECW/TBW is more than 0.400, edematous situation would be supposed, especially in PTE in lower legs [9]. As segmental body PhA, case 2 showed remarkable low data of 0.5, where he has suffered from continuous pain in right leg, knee and foot. These impaired function and inflammatory situation would bring low results of PhA, because PhA can suggest cell function and clinical symptoms, signs and impaired function. Thus, comparing both cases of same physiques, large difference of several biomarkers or parameters can be found.

For evaluation of clinical nutrition, PhA seems to be convenient for indicating the function level. This is from water distribution in human body and presenting proxy of body cell [15]. Furthermore, it can suggest muscle amount and strength that indicate useful predictor for some clinical reports. Concerning segmental PhA from BIA, clinical significance has been reported. The segmental BIA seems to be an important method for assessment of body composition of for several body segments, including the arms, legs and so on [16]. Segmental PhA value seems to be useful parameter for suggesting muscle quality situation of affected or unaffected extremities by separate aspect. It may become accurate marker for evaluating rehabilitation efficacy for patients with hemiplegia, since it can distinguish impaired limb from healthy limb. Then, it will possibly monitor clinical improvement of muscle function or quality through a series of rehabilitation program.

PhA has been known for the indicator of cellular health, including cell membrane integrity, cell function and higher cellularity. PhA value and physical activity were studied for their relationship [17]. Cases were 115 applicants for 30s-60s. Exercise habit was divided into 3 groups, which were resistance training exercise habit (RT), aerobic training exercise habit (AT) and no exercise (No-Ex) groups. Then, PhA of RT and AT was remarkably higher than no-Ex. There was no significant difference between RT and AT. Thus, continuing regular exercise with moderate to high intensity can maintain/improve cellular health and muscle quality. RT is known for valid exercise against aging process on muscle mass, in which BIA can evaluate this situation. RT efficacy for the elderly was studied for systematic review [18]. From 344 cases (7 reports), quality evaluation was shown as 71.3% of score. When keeping RT for eight weeks, PhA increased as 0.52 degree for clinical investigation significantly.

Certain limitation may be present in this report.  It included two cases who received BIA exam, and obtained data were compared. Some differences are suggested from various aspects, such as aging, diabetes, cell health, edematous situation, muscle volume or function, physiological efficacy and so on [19]. Clinical progress would be followed up associated with close attention with BIA analyses.

In summary, two applicants with sports experience were shown and compared by ECW/TBW and PhA. This article will become hopefully useful reference report with BIA, water balance and anti-aging medicine.

Acknowledgements

We appreciate the participants and related researchers for sincere cooperation and assistance.

Ethical consideration

The study was approved by the Ethics Committee of our institution, and was conducted in accordance with the Declaration of Helsinki of 1996. It also complied with the Ethical Guidelines for Medical Research Involving Human Subjects of 2017. The informed consent was taken from the applicants by the written documents.

Conflict of interest

The authors declare that there is no conflict of interest.

Funding

Current research did not receive any specific grants or funding from public, commercial, or not-for-profit organizations, agencies or sectors.

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