Abstract
ckground:Experimental studies suggest that mineral waters with high concentrations of calcium and bicarbonate can impact acid–base balance. The purpose of this study was to test the effect on acid–base balance and specific urine gravity, of a bicarbonate calcic mineral water (Acqua Lete W ) compared to a minimally mineralized water. Methods:88 amateur male athletes underwent two experimental trials with a modified Wingate test: the first was carried out without hydration (Control Test, Test C, n = 88); the second was carried out after one week of controlled hydration (Test with hydration, Test H, n = 88), with 1.5 L/day of a very low mineral content water (Group A, n = 44) or 1.5 L/day of Acqua Lete W (Group B, n = 44). Measure of body temperature, bioimpedance analysis, muscular ultrasound, and urinalysis were taken before (t0), immediately after (t 1), 5’(t 2), and 30’(t 3) after exercise. Results:Hydration results in a decreased core temperature; muscular ultrasound showed increased muscle thickness after exercise related to content of body water. Regarding urinalysis, in test H, we found in both groups after exercise a significant decrease of specific urine gravity with significantly lower levels in Group B. We also found a significant increase of pH in the same Group B. Conclusions:In conclusion all the athletes hydrated with Acqua Lete W showed a positive impact on hydration status after anaerobic exercise with significant decrease of specific urine gravity and a positive effect on pH. Keywords:Acqua Lete W mineral water, Urine specific gravity, Urine pH, Intracellular body water, Muscular ultrasound Background Scientists and athletes pay particular attention to the strategies of water intake in order to guarantee the best balance of fluids and to improve performance [1,2]. American College of Sports Medicine and the National Athletic Trainers' Association have defined hydration- status founding on urine specific
Lete W mineral water, Urine specific gravity, Urine pH, Intracellular body water, Muscular ultrasound Background Scientists and athletes pay particular attention to the strategies of water intake in order to guarantee the best balance of fluids and to improve performance [1,2]. American College of Sports Medicine and the National Athletic Trainers' Association have defined hydration- status founding on urine specific gravity [3,4]. In 1996 the American College of Sport Medicine established the guideline, recently confirmed [5], recommended to pre- serve an optimal balance of hydration in order to im- prove performance and to prevent injuries. Natural, untreated, spring water distinguishes itself from other bottled waters by its specific underground geological origin, its stable composition of minerals and its purity. Mineral waters can have potential beneficial effects on health [6], including bone health and numer- ous health claims have been made for the benefits aris- ing from the traces of a large number of minerals found in solution [7]. Water alone provides adequate hydration during performance [8]; several researchers have sug- gested, for instance, that mineral waters, especially those with high concentrations of calcium and bicarbonate, can impact acid–base balance [9] and contribute to the prevention of bone loss [10]. Alkalinizing mineral waters can influence the acid– base equilibrium of the body [11]. Even small changes in * Correspondence:rastrelli@unisa.it 4 Dipartimento di Scienze Farmaceutiche e Biomediche, University of Salerno, Via Ponte Don Melillo, Fisciano, Salerno 84084, Italy Full list of author information is available at the end of the article © 2012 Brancaccio et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Brancaccioet al. Journal of the International Society of Sports Nutrition2012,9:35 http://www.jissn.com/content/9/1/35
pH have crucial effects on cellular function, suggesting that the purposeful consumption of mineral water repre- sents one of the most practical ways to increase the nu- tritional load of alkali to the body. On the other hand, several studies have shown that alkalinizing mineral waters low in SO 4 2-and rich in HCO 3 -had better effects on Ca metabolism and bone resorption markers than waters rich in SO 4 2-and Ca [12]. Acqua Lete W mineral water has calcium concentra- tions of 314 mg/L, magnesium of 15 mg/L and bicar- bonate of 981 mg/L, being a very high calcium and bicarbonate mineral water. The Acqua Lete W exhibits other peculiarities, notably high levels of carbon dioxide, and low contents of sodium and potassium. Objectives of this study were to examine the relation- ship between Acqua Lete W intake and total body water, muscle thickness and urinary markers of hydration after short term anaerobic exercise. Based on experimental evidence, we hypothesized that Acqua Lete W mineral water ingestion will correlate with acid–base balance in the body lowering specific urine gravity of athletes and that it can guarantee the effectiveness of a correct hydra- tion during short term exercise. Methods Protocol All testing procedures were approved by the institution’s Human Research Ethics committee. Eighty-eight male amateur athletes volunteered to participate in the study. All potential participants attended a familiarization ses- sion where details of the test protocol and their time commitment were described. All participants were advised that they were free to withdraw from testing at any time without any adverse consequences. Upon com- pletion of the consent form, participants were randomly divided in two groups (A and B groups) of 44 subjects. Athletes trained (swimming or running) 4–5 hours per week. All the subjects stopped the training and followed a diet without any kind of mineral supplements during the entire period of the study (2 weeks). Group A : age 34.7 y ± 7.4 (mean ± S.D.); height 178.5 cm ± 5.6; weight 79.6 kg ± 6.9, and Body Mass Index (BMI) 24.6 ± 1.2. Group B : age
per week. All the subjects stopped the training and followed a diet without any kind of mineral supplements during the entire period of the study (2 weeks). Group A : age 34.7 y ± 7.4 (mean ± S.D.); height 178.5 cm ± 5.6; weight 79.6 kg ± 6.9, and Body Mass Index (BMI) 24.6 ± 1.2. Group B : age 33.7 y ± 8.6 (mean ± S.D.); height 174.6 cm ± 5.4; weight 79.6 kg ± 9.6, and Body Mass Index (BMI) 25.7 ± 3.4. Both groups underwent two experimental trials, per- formed on an electrically braked ergometer (Bycicle SECA Hamburg, Germany) with a modified repeated Wingate protocol: five bouts of cycling of 60”with a mean speed of 80 RPM and 60”of rest between the ses- sions. The workload was 85 % of their maximal work- load computed in a preliminary session a week before the first Test, with an incremental test on bicycle until exhaustion. The two Tests were: test C of control, in basal condi- tions and without hydration the day of trial, for both groups and test H, after one week of controlled hydra- tion with 1.5 L/die of a very low mineral content water in group A and 1.5 L/die of Acqua Lete W , a bicarbonate calcic water with a medium mineral content in group B. Moreover athletes received 750 ml of water using freshly opened bottles one hour before the exercise and 250 ml of water in the following 30 minutes after effort, as recommended by National Athletic Trainer Associ- ation [4]. The type of water used was still the very low mineral content water (Group A) and Acqua Lete W (Group B). Before testing, participants received a physical examin- ation including medical history. In each session of work (Test C and Test H), we measured: body temperature; total body water (TBW), extracellular water (ECW), intracellular water (ICW); muscular size of quadriceps femoris; urinalysis. The timing of measurements were: at rest before the exercise (t 0):body temperature, bioimpedance analysis for TBW, ECW and ICW, muscular ultrasound for detection of muscular size, urinalysis; immediately after
In each session of work (Test C and Test H), we measured: body temperature; total body water (TBW), extracellular water (ECW), intracellular water (ICW); muscular size of quadriceps femoris; urinalysis. The timing of measurements were: at rest before the exercise (t 0):body temperature, bioimpedance analysis for TBW, ECW and ICW, muscular ultrasound for detection of muscular size, urinalysis; immediately after the last session of exercise (t 1):body temperature; 5 minute after exercise (t 2):bioimpedance analysis, muscular ultrasound examination; 30 minutes after exercise (t 3):urinalysis; Water analysis The bicarbonate-rich mineral water Acqua Lete (Acqua Lete W ; Società Generale delle Acque Minerali, Pratella, CE, Italy), consumed by the experimental Group B was shipped directly to the testing lab from its bottling facil- ity. The very low mineral content water used for Group A is commonly available throughout Italy; it does not contain significant minerals or electrolytes whatsoever. Very low mineral content and Acqua Lete waters were also analyzed for 15 chemical parameters in our labora- tory. Most of the elements were determined by ion chro- matography (IC) using a Dionex instrument. A non- acidified aliquot was used to determine pH, electrical conductivity (EC), to titrate alkalinity. The 15 chemical and chemical-physical variables measured on each sam- ple are listed in Table 1. Analytical methods are not fur- ther discussed here since they represent standard methods fixed by Italian regulations (IRSA–CNR meth- ods 1994). Results are expressed as mean values ± SD (standard deviation) of three replicate analyses for each water. Brancaccioet al. Journal of the International Society of Sports Nutrition2012,9:35 Page 2 of 7 http://www.jissn.com/content/9/1/35
Body temperature The Measurement of body temperature was made by means of tympanic thermometer Braun ThermoScan. Bioimpedance analysis The qualitative and quantitative appraisal of the body composition was made by means of instrumentation Bodygram AKERN, Florence Italy, which evaluates body and tissue composition, hydration and nutrition status. BIA methods are based on empirical equations based on height, weight and resistance or impedance of the wrist-ankle at 50 kHz, and allows determination of fluid volume and total body water from measurements of resistivity of tissues. We estimated the following para- meters: total body water (TBW), extracellular body water (ECW) and intracellular body water (ICW). The examination at T0 was performed fasting from food and drink, whereas at T2 after the controlled hydration. Muscle ultrasound Muscle thickness were determined on the right leg by ultrasonography with a 10 MHz probe with the subject sitting on the examination couch with hips and knees flexed at 90° as reported previously. Muscular ultra- sound is a non invasive, available method to detect dif- ferences in muscular size after exercise [13]. Subjects were asked to stay relaxed. The same operator per- formed all measurements at the border between the lower one third and the upper two thirds of the dis- tance between the anterior superior iliac spine and the upper pole of the patella. The measuring point was marked with a marking pen. Measurements were per- formed just before the exercise test (t 0), and 5 minute after the end of the cycloergometer test (t 2). We mea- sured the thickness of the quadriceps femoris (rectus femoris + vastus intermedius) with the probe placed in the transverse plane. Urinalysis The urine was collected in polyethylene containers and mixed with 5 ml/L of a 5 % solution of thymol in isopro- panol to preserve the urine. During the collection period, the containers and their contents were main- tained at 5 °C. Urine samples were tested for the pres- ence of blood and infection. Nitrite-positive and haematuria samples were discarded. Urine Specific Grav- ity was evaluated using a refractometer (Atago Digital Urine Specific Gravity Refractometer). Urine pH was
of thymol in isopro- panol to preserve the urine. During the collection period, the containers and their contents were main- tained at 5 °C. Urine samples were tested for the pres- ence of blood and infection. Nitrite-positive and haematuria samples were discarded. Urine Specific Grav- ity was evaluated using a refractometer (Atago Digital Urine Specific Gravity Refractometer). Urine pH was recorded using a Rondolino sample changer potentiom- eter (Mettler Toledo). The color of the urine has been evaluate using a visual staircase. Vogel 1 (yellow urine, yellow pale, yellow clear), Vogel 2 (yellowish urines, red- dish, redheads), Vogel 3 (red brownish and brown urines). 2 (yellowish urines, reddish, redheads), Vogel 3 (red brownish and brown urines). Statistical analyses Statistical analysis was performed by SPSS statistical package for Windows, release 17.0 (Chicago, IL, USA). We compared the data collected in each group at every step of work. Statistical significance between group A and group B was evaluated by unpaired samplesTTest : descriptive statistics were calculated, and values reported as mean ± SD. Statistical significance within group A and group B, comparing Test C and Test H, was also evalu- ated by Student’sTTest for paired samples: descriptive statistics were calculated, and values are reported as mean ± standard deviation. Relationships between the measures collected were calculated with a bivariate cor- relation measuring the Pearson’s correlation coefficient. Differences were considered statistically significant when P≤0.05. Results and discussion All of the subjects underwent the protocol as described. In Table 1 we reported the features of the mineral waters used in the study. Tests were performed at an environmental temperature of 19.50 ± 0.53 °C with a wetness of 58.38 ± 0.52 %. Test C In the first test made without hydration, the body temperature showed a significant increase immediately at the end of the cycloergometer test: the athletes started Table 1 Chemical characteristics of mineral waters used in the study* Parameter Measurement unit Acqua Lete W Very low mineral content Conductivity mS/cm 1321.40 ± 46.10 17.57 ± 0.91 pH pH 6.14 ± 0.11 5.00 ± 0.09 Fixed residue mg/l 878.41 ± 25.21 14.31 ±
showed a significant increase immediately at the end of the cycloergometer test: the athletes started Table 1 Chemical characteristics of mineral waters used in the study* Parameter Measurement unit Acqua Lete W Very low mineral content Conductivity mS/cm 1321.40 ± 46.10 17.57 ± 0.91 pH pH 6.14 ± 0.11 5.00 ± 0.09 Fixed residue mg/l 878.41 ± 25.21 14.31 ± 0.68 CO 2 mg/L 1890.12 ± 72.51 15.22 ± 0.77 HCO3 - mg/l 981.11 ± 33.82 3.51 ± 0.15 Cl - mg/l 8.24 ± 2.22 0.41 ± 0.02 SO 4 2- mg/l 6.60 ± 0.91 1.40 ± 0.08 NO 3 - mg/l 4.14 ± 0.20 1.91 ± 0.08 Na + mg/l 4.91 ± 0.33 1.21 ± 0.05 K + mg/l 2.10 ± 0.08 0.32 ± 0.01 Ca ++ mg/l 313.70 ± 9.81 1.11 ± 0.05 Mg ++ mg/l 15.12 ± 3.92 0.42 ± 0.03 Fe mg/l 0.02 ± 0.01 <0.01 Sr ++ mg/l 0.15 ± 0.01 <0.1 Li + mg/l <0.01 <0.01 *Each results represents the mean ± SD of three analysis for each water. Brancaccioet al. Journal of the International Society of Sports Nutrition2012,9:35 Page 3 of 7 http://www.jissn.com/content/9/1/35
exercise with a mean temperature of 35.9 ± 0.6 °C, reach- ing at the end of work 36.5 ± 0.4 °C; (p<0.001). No dif- ferences were perceived in total body water distribution, with almost the same levels of ICW and ECW detected before (t 0) and 5 minute after exercise (t 2). Conversely significant changes were detected in TBW during the test C (Table 2). Ultrasonography performed at rest (t 0) and 5’after the Wingate test (t 2) showed in both groups a variation of muscular thickness, consistent with our previous study [11]. (Group A: 29.94 ± 3.89 mmvs32.29 ± 3.13 mm: p = 0.00); Group B: 30.56 ± 3.30 mmvs33.08 ± 2.89 mm: p = 0.00). Urinalysis collected at t 0and t 3showed no significant difference in colour; we observed a decrease of urinary pH at t 2(Table 3), as expected after anaerobic exercise, whereas specific urinary gravity after effort (Figure 1) showed a significant increase (Group A: 1020 ± 4.7 g/L vs1022 ± 4.4 g/L; p =<0.001; Group B: 1018 ± 6.5 g/Lvs 1019 ± 5.5 g/L; p = ns). Data on urine pH and specific gravity between the two groups were compared. The values were not different between the two groups. Test H The body temperature showed an increase t 0-t 1in test C (35.9 ± 0.4 °Cvs36.4 ± 0.4 °C; p =<0.001). Bioimpedance analysis performed after hydration (Table 2), showed no difference in group A, whereas in group B we found a slight but significant decrease of ECW at rest and a con- comitant increase of ICW. After exercise group B showed a shift of body water, from extracellular to intra- cellular compartment. Ultrasonography detected an increase in muscular thickness, in test H. (Group A: 29.93 ± 3.89 mmvs 32.00 ± 3.61 mm; Group B: 30.84 ± 3.47 mm vs 32.82 ± 2.72 mm). In athletes hydrated with Acqua Lete urine pH was more alkaline than in those who drank very low mineral content water (Table 3). The specific gravity of the urine after effort sustained a significant and similar decrease in the two groups but
± 3.89 mmvs 32.00 ± 3.61 mm; Group B: 30.84 ± 3.47 mm vs 32.82 ± 2.72 mm). In athletes hydrated with Acqua Lete urine pH was more alkaline than in those who drank very low mineral content water (Table 3). The specific gravity of the urine after effort sustained a significant and similar decrease in the two groups but subjects who drank Acqua Lete mineral water (Group B) showed a significantly lower mean values of specific urinary gravity when compared with athletes belonging to Group A (Group A 1014 ± 4.1 g/L vs Group B 1008 ± 4.3 g/L - Figure 2). Many studies used Wingate Test and modified Win- gate Test [14], to assess physiological responses to anaer- obic exercise. In our study we evaluated the response to anaerobic exercise before and after hydration with a bicarbonate-calcic mineral water, named Acqua Lete, compared to a very low mineral content water (dry resi- dues 14.3 mg/L). A modest increase in core body temperature occurred despite subjects performed at a moderately high exercise intensity for a short time, although there are not uni- vocal conclusions in the literature about the relation be- tween core temperature, intensity of exercise and hydration status [15]. However some studies reported in- crease of core temperature after Wingate test, with a fa- tigue index higher when core temperature values are highest [16]. The exact mechanism of fatigue is not known; but presumably it is a complex interplay be- tween both peripheral and central factors: the mechan- ism is probably mediated by catecholamines dopamine and noradrenaline. [17]. Table 2 Total body water (TBW), Extracellular water (ECW) and Intracellular water (ICW) in Test C (control) and in Test H (hydration) before and after exercise* Test C TBW ECW ICW t 0 t 3 t 0 t 3 t 0 t 3 Group A 56.69 ± 1.14 a 55.30 ± 1.05 a 40.60 ± 2.48 41.20 ± 2.84 59.40 ± 2.40 58.81 ± 2.84 Group B 57.50 ± 1.80 b 55.87 ± 0.75 b 37.76 ± 4.17 37.46 ± 2.82 62.24 ± 4.17 62.54 ± 2.82 Test H
ECW ICW t 0 t 3 t 0 t 3 t 0 t 3 Group A 56.69 ± 1.14 a 55.30 ± 1.05 a 40.60 ± 2.48 41.20 ± 2.84 59.40 ± 2.40 58.81 ± 2.84 Group B 57.50 ± 1.80 b 55.87 ± 0.75 b 37.76 ± 4.17 37.46 ± 2.82 62.24 ± 4.17 62.54 ± 2.82 Test H TBW ECW ICW t 0 t 3 t 0 t 3 t 0 t 3 Group A 57.83 ± 3.75 57.43 ± 5.01 40.85 ± 2.87 40.57 ± 2.42 59.15 ± 2.87 59.43 ± 2.42 Group B 57.84 ± 2.26 57.37 ± 3.11 38.47 ± 1.11 c 37.10 ± 1.04 c 61.53 ± 1.14 d 62.94 ± 0.94 d * values are expressed in percentage (%). Data are expressed as mean ± SD: n = 44. Mean values were significantly different from resting values (t 0): a and b p<0.001; c and d p<0.05. Table 3 Urine pH detected in Test C (control) and in Test H (hydration) before and after Exercise* Test C t 0 t 2 Group A 5.6 ± 0.2 a 5.3 ± 0.1 a Group B 5.6 ± 0.4 5.4 ± 0.5 Test H t 0 t2 Group A 5.5 ± 0.8 5.4 ± 0.9 Group B 5.4 ± 0.2 b 5.7 ± 0.1 b * Data are expressed as mean ± SD, n = 44. Mean values were significantly different: a and b p<0.05. Brancaccioet al. Journal of the International Society of Sports Nutrition2012,9:35 Page 4 of 7 http://www.jissn.com/content/9/1/35
Other studies reported increase of temperature after light exercise, as the warm-up, depending on the dur- ation of exercise [18]. The relationship between level of hydration and core temperature has been widely studied and, although it is well documented that dehydration increases body temperature during exercise [19], many studies agree that hyperhydration provides no thermo- regulatory advantage over the maintenance of euhydra- tion during exercise [20]. In our study we found a slight but significant difference in body temperature after exercise between Test C and Test H (36.5 ± 0.4 °C vs36.4 ± 0.4 °C; p =<0.001), with lower values after hy- dration, confirming that the euhydration obtained in the second test ensured a better thermoregulatory homeostasis. Body composition assessment is useful in a variety of clinical settings to gain information about nutritional condition and the status of body fluid compartments. Bioimpedance analysis (BIA) is an attractive technique for the purpose, because it is safe, non-invasive, inexpensive and easy to use. Previous studies have char- acterized the accuracy of bioimpedance analysis [21] and have reported difference in total body water before and after effort, due to a shift from extracellular to intracel- lular compartment consequent to modification of cellu- lar osmolarity after energy depletion [22,23]. During exercise, the elevated metabolic activity within the cell, leads to increased osmotic pressure, stimulates an influx of fluid into the intracellular compartment to re- establish an osmotic equilibrium [24]. Although changes in TBW are reported in the litera- ture as a consequence of long-term exercise [25], we found significant change of TBW in both groups, when not hydrated. Conversely, after hydration both groups showed a similar total body water, but different distribu- tion of ECW and ICW: Group B, hydrated with a bicar- bonate calcic mineral water (Acqua Lete W ), showed a significant shift of water through intracellular comparti- ment. This group reached at peak of exercise a higher level of blood lactate (9.8 ± 0.6 mmol/Lvs7.4 ± 0.8 mmol/L; p<0.05), leading to a change of intracellular pH and mediating cellular osmolality, which may be responsible for the increased volume of water in
Description
The study evaluates hydration effects of Acqua Lete W in athletes post-exercise.