Renal protein excretion after exercise in man

Match Analysis, Physical Training, Risk of Injury and Rehabilitation in Padel: Overview of the Literature

Padel is a racket sport that has been gaining great popularity and scientific interest in recent years. It could be considered to be a high-intensity intermittent sport with valuable cardiovascular and neuromuscular benefits; however, the risk of injury cannot be neglected. To date, there is still a gap of knowledge in the scientific literature on this emergent sport. Therefore, the present review aims to synthetize the current knowledge on padel game dynamics to better characterize the main risk factors, the injury rate and characteristics, and the most effective rehabilitative treatment strategies. PubMed, Scopus, Cochrane, and PEDro were screened up to January 2022 to identify eligible studies focusing on padel players as participants. Out of 160 records, we included 19 studies, which were focused on match analysis, anthropometric and physical training, the risk of injury, and rehabilitative interventions. The results showed that the high action velocity and the sudden changes in direction during a padel match could represent a risk factor for injuries, especially in untrained players. However, the high heterogeneity of the studies in the literature hinders our ability to draw any strong conclusions, and the results should be carefully considered. Future research should address the lack of knowledge on injury mechanisms and type to implement a tailored rehabilitation program.

Gender Differences in Neuromuscular, Haematological and Urinary Responses during Padel Matches

Research on the acute physiological response to a padel match is limited. The present study aimed to: (a) evaluate neuromuscular, urinary, and hematological responses after simulated padel competition (SC) and (b) analyze possible gender differences. In this study, 28 high-level padel players participated (men = 13, age = 26.83 ± 6.57 years; women = 15, age = 30.07 ± 4.36 years). The following parameters were analyzed before and after SC: neuromuscular (hand grip strength, squat jump (SJ), countermovement jump (CMJ), and Abalakov jump (ABK)), hematological (red blood cells, hemoglobin, and hematocrit), and urinary (pH, specific gravity, microalbuminuria, and red blood cells). Significant gender differences were found in neuromuscular and hematological responses, with men obtaining higher values (p < 0.05). For the SC influence, changes were noted in ABK and microalbuminuria (p < 0.05). The percentages of change in hand grip strength, SJ (height and watts), CMJ (height), and ABK (height) were higher for men than women (p < 0.05). SC negatively influenced the neuromuscular parameters to a greater extent in women. Our results could be related to gender differences in game actions, the temporal structure, and anthropometric and physiological characteristics. Game dynamics and a different organic response between male and female padel playing were confirmed.

Urinary Biomarkers: Diagnostic Tools for Monitoring Athletes' Health Status

Acute or intense exercise is sometimes related to infections of the urinary tract. It can also lead to incorrect hydration as well as incorrect glomerular filtration due to the presence of high-molecular-weight proteins that cause damage to the kidneys. In this context, our study lays the foundations for the use of a urine test in a team of twelve male basketball players as a means of monitoring numerous biochemical parameters, including pH, specific weight, color, appearance, presence of bacterial cells, presence of squamous cells, leukocytes, erythrocytes, proteins, glucose, ketones, bilirubin, hemoglobin, nitrite, and leukocyte esterase, to prevent and/or treat the onset of pathologies, prescribe personalized treatments for each athlete, and monitor the athletes’ health status.

Factors influencing post-exercise proteinuria after marathon and ultramarathon races

Post-exercise proteinuria is one of the most common findings observed after short and intensive physical activity, but is observed also after long runs with low intensity. The aim of this study was to analyze factors influencing proteinuria after marathon runs. Two groups of male amateur runners were studied. The results of 20 marathon finishers (42.195 m), with a mean age of 49.3 ± 6.85 years; and 17 finishers of a 100-km ultramarathon with a mean age of 40.18±4.57 years were studied. Urine albumin to creatinine ratio (ACR) was calculated before and after both races. The relationship between ACR and run pace, metabolites (lactate, beta hydroxybutyrate), markers of inflammation (CRP, IL-6) and insulin was studied. The significant increase in ACR was observed after both marathon races. ACR increased from 6.41 to 21.96 mg/g after the marathon and from 5.37 to 49.64 mg/g after the ultramarathon (p<0.05). The increase in ACR was higher after the ultramarathon that after the marathon. There was no correlation between run pace and proteinuria. There was no correlation between ACR and glucose, free fatty acids, lactate, beta-hydroxybutyrate and insulin levels. There was significant negative correlation between ACR and interleukin 6 (IL-6) (r =-0.59, p< 0.05) after ultramarathon. Proteinuria is a common finding after physical exercise. After very long exercises it is related to duration but not to intensity. There is no association between metabolic and hormonal changes and ACR after marathon runs. The role on inflammatory cytokines in albuminuria is unclear.

Acute exercise does not impair renal function in nondialysis chronic kidney disease patients regardless of disease stage

Exercise has been overlooked as a potential therapy in chronic kidney disease (CKD), mainly because of a lack of understanding on its safety aspects. Notably, there are no data on renal function after exercise in CKD considering its stages. We investigated the acute effects of a 30-min moderate-intensity aerobic exercise bout on glomerular filtration rate (GFR) and albuminuria in 22 nondialysis CKD patients divided into: CKD stages 1 and 2 (CKD_1-2) and CKD stages 3 and 4 (CKD_3-4). Eleven body mass index-, age-, and sex-matched healthy individuals served as control (CON). Blood and urine samples were collected before, immediately after, and up to 90 min postexercise for creatinine and albumin assessments. GFR was determined by creatinine clearance (GFR_Cr-Cl). All CKD patients had significantly lower peak oxygen uptake than CON. CKD_1-2 and CKD_3-4 had increasingly higher serum creatinine than CON (9.6 ± 2.6, 25.6 ± 1.01, and 7.5 ± 1.4 mg/l, respectively); however, no within-group changes in serum or urinary creatinine were observed across time. GFR_Cr-Cl was decreased in CKD_1-2 and CKD_3-4 compared with CON (91 ± 17 ml·min^-1·1.73 m^-2; 34 ± 15 ml·min^-1·1.73 m^-2; 122 ± 20 ml·min^-1·1.73 m^-2, respectively). Most importantly, exercise did not affect GFR_Cr-Cl in none of the groups across time. Albuminuria was significantly higher in CKD_3-4 (297 ± 284 µg/min) than in CON (5.4 ± 1.4 µg/min), but no within-group changes were observed after exercise. In conclusion, a single 30-min moderate-intensity aerobic exercise bout does not impair renal function in nondialysis CKD patients, regardless of disease stage, supporting the notion that exercise training can be safe in this disease.

Half-ironman induces changes in the kidney function of triathletes

Long duration exercise may lead to the occurrence of urine abnormalities. Aiming to investigate the effects of triathlon training and competition on the renal function, twelve male triathletes (32.60 ± 5.10 years, 175.04 ± 6.67m, 71.83 ± 7.42Kg) were studied during the 12-week training protocol and after a Half Ironman. Urine was collected in M-1 - beginning of the training season, M-2 - before the competition and M-3 - after the half ironman. Urine pH was measured using reagent strips, density with a refractometer, proteinuria by Bradford assay, creatinine with a colorimetric assay and blood cells by microscopy. Data were analyzed using Shapiro-Wilk test, One-Way ANOVA and Tukey-Kramer test (p < 0,05). Changes were found after the competition in the protein (M-1= 7.41 ± 2.48; M-2= 7.57 ± 3.74; M-3= 86.10 ± 76.21 mg/mL), creatinine (M-1= 157.66 ± 41.59; M-2= 177.68 ± 44.46; M-3= 316.46 ± 132.86 mg/mL), erythrocytes (M-1= 1060.00 ± 0.30; M-2= 1142.86 ± 377.96; M-3= 52555.56 ± 58.65 units/mL) and leucocytes (M-1= 2375.00 ± 744.02; M-2= 2090.00 ± 0.50; M-3= 5000.00 ± 2738.60 units/mL) excretion when compared to the other collection times. These effects are probably due to the exercise-induced modifications in the glomerular membrane and endocrine variables such as anti diuretic hormone, catecholamines and aldosterone.

Microalbuminuria, kidney function, and daily physical activity

The present study was carried out to investigate independent relationship between daily physical activity, microalbuminuria, and kidney function. The demographic characteristics and laboratory parameters were recorded for all patients. The determination of daily activities was carried out by Nottingham Extended Activities of Daily Living Scale (NEADLS) which was performed for each patient in an interview. Totally 139 patients were enrolled. In the whole group NEADLS score was correlated with age (rho: −0.759, P < 0.0001), clinical systolic blood pressure (rho: −0.212, P: 0.018), blood urea nitrogen (rho: −0.516, P < 0.0001), creatinine (rho: −0.501, P < 0.0001), uric acid (rho: −0.308, P < 0.0001), albumin (rho: 0.382, P < 0.0001), total cholesterol (rho: −0.194, P: 0.022), LDL-cholesterol (rho: −0.230, P: 0.008), hemoglobin (rho: 0.256, P: 0.002), creatinine clearance (rho: 0.565, P < 0.0001), 24-hour urinary protein excretion (rho: −0.324, P < 0.0001), and 24-hour urinary albumin excretion (UAE) (rho: −0.483, P < 0.0001). The multivariate linear regression of independent factors corelated with logarithmically converted NEADLS score (as a dependent variable) has shown that age (P < 0.0001), presence of coronary artery disease (P: 0.011), hemoglobin (P: 0.020), 24-hour creatinine clearance (P: 0.004), and 24-hour urinary albumin excretion (P < 0.0001) were independently corelated with NEADLS score. In conclusion, both UAE and kidney function were independently associated with daily physical activity.

Utility of urinary Clara cell protein (CC16) to demonstrate increased lung epithelial permeability in non-smokers exposed to outdoor secondhand smoke

The objective of this study was to assess the utility of urinary Clara cell protein (CC16) as a biomarker of increased lung epithelial permeability in non-smokers exposed to outdoor secondhand smoke. Twenty-eight healthy non-smoking adults visited outdoor patios of a restaurant and a bar where non-participants smoked and an open-air control with no smokers on three weekend days in a crossover study; subjects visited each site once for 3 h. Urine samples were collected at baseline, immediately post exposure and next morning, and analyzed for CC16. Changes in CC16 across location types or with cigarette count were analyzed using mixed-effect models, which included all subjects and stratified by gender. Urinary CC16 was higher in males (n=9) compared with females (n=18) at all measurement occasions (P<0.002), possibly reflecting prostatic contamination. Urinary CC16 from pre-exposure to post-exposure was higher following visits to restaurant and bar sites compared with the control among females but this increase did not reach statistical significance. Post-exposure to pre-exposure urinary CC16 ratios among females increased with cigarette count (P=0.048). Exposure-related increases in urinary CC16 were not seen among males. In conclusion, urinary CC16 may be a useful biomarker of increased lung epithelial permeability among female non-smokers; further work will be required to evaluate its applicability to males.

Physical activity and albuminuria

Higher urinary albumin excretion predicts future cardiovascular disease, hypertension, and chronic kidney disease. Physical activity improves endothelial function so activity may reduce albuminuria. Among diabetics, physical activity decreases albuminuria. In nondiabetics, prior studies have shown no association. The authors explored the cross-sectional association between physical activity and albuminuria in 3,587 nondiabetic women in 2 US cohorts, the Nurses' Health Study I in 2000 and the Nurses' Health Study II in 1997. Physical activity was expressed as metabolic equivalents per week. The outcome was the top albumin/creatinine ratio (ACR) decile. Multivariate logistic regression was used. Secondary analyses explored the ACR association with strenuous activity and walking. The mean age was 58.6 years. Compared with women in the lowest physical activity quintile, those in the highest quintile had a multivariate-adjusted odds ratio for the top ACR decile of 0.65 (95% confidence interval (CI): 0.46, 0.93). The multivariate-adjusted odds ratio for the top ACR decile for those with greater than 210 minutes per week of strenuous activity compared with no strenuous activity was 0.61 (95% CI: 0.37, 0.99), and for those in the highest quintile of walking compared with the lowest quintile, it was 0.69 (95% CI: 0.47, 1.02). Greater physical activity is associated with a lower ACR in nondiabetic women.

No change of body mass, fat mass, and skeletal muscle mass in ultraendurance swimmers after 12 hours of swimming

We evaluated whether ultraendurance swimmers suffer a change of body mass, fat mass, skeletal muscle mass, total body water and specific gravity of urine during a 12-hr swim in 12 male Caucasian ultraswimmers. Proton nuclear magnetic resonance of urine samples before and after the race was performed to detect alanine, lactate, and 3-hydroxybutyrate. The 12 swimmers achieved an average distance of 29.4 km (SD = 5.1). No statistically significant changes in body mass, fat mass, skeletal muscle mass, and total body water could be determined (p > .05), but urine gravity decreased significantly (p < .001). Two participants showed increased signals of ketone bodies after the race. In these samples, the hydroxybutyrate-creatinine ratio increased more than tenfold.

Renal alterations during exercise

Proteinuria and hematuria are common during exercise. Proteinuria is usually due to glomerular or tubular changes or to an excessive production of protein as in myeloma. Certain clinical conditions can, however, result in a functional or temporary proteinuria, especially during pregnancy, fever, orthostasis, or following physical activity. Sport-related proteinuria following marching, exercise, and stress, was first observed in soldiers after long marching. Prevalence of proteinuria during exercise ranges from 18% up to 100% depending on type of exercise and its intensity. A higher incidence of proteinuria has been observed in some sports requiring great exercise intensity and it is certainly related to muscular work intensity and would decrease after prolonged training. Indeed, exercise-induced proteinuria is strictly related to exercise intensity rather than to exercise duration. Exercise aggravates the proteinuria of various nephropathies and that of renal transplant recipients. The prevalence of hematuria is higher in the athletic than the general population and the main difference is that sport-related hematuria resolves spontaneously after physical exercise while hematuria found in nonathletic population can be chronic. Sport-induced hematuria is influenced by exercise duration and intensity. Among the mechanisms underlying the exercise induced hematuria are increased body temperature, hemolysis, increased production of free radicals, and excessive release of catecholamines. Lactic acidosis, generated during anaerobic conditions, causes the passage of erythrocytes into the urine, through increased glomerular permeability.

Biphasic Pattern of Exercise-Induced Proteinuria in Sedentary and Trained Men

BACKGROUND/AIMS

Exercise-induced proteinuria is a common consequence of physical activity, although its mechanism is not clear. Oxidant stress has been proposed as one of different factors involved in postexercise proteinuria in rats. In this study we investigated whether reactive oxygen radicals generated during exercise play a role in exercise-induced proteinuria in sedentary and trained men.

METHODS

The validity of oxidant stress following stepwise maximal exercise on proteinuria was investigated in sedentary and trained subjects before and after antioxidant vitamin treatment (A, C, and E) for 2 months. While protein carbonyl content in serum and thiobarbituric acid reactive substances (TBARS) in erythrocytes and urine were used as oxidant stress markers, total protein, albumin, beta(2)-microglobulin in urine were assayed for proteinuria in five consecutive specimens after exercise. Urines were collected before exercise, then 30 min, 2, 8 and 24 h postexercise.

RESULTS

Increased urinary protein levels and mixed type proteinuria were determined after 30 min of exercise in sedentary and trained subjects. Proteinuria was normalized at 2 and 8 h specimens. However, glomerular type proteinuria was identified at 24 h specimen in both groups. Oxidant stress markers were significantly elevated in sedentary and trained subjects. Antioxidant treatment prevented the increase in oxidant stress markers, urinary protein levels and the occurrence of glomerular type proteinuria after exhaustive exercise at 24 h in both groups.

CONCLUSIONS

These findings suggest that the exercise-induced oxidant stress may contribute to exercise-induced proteinuria in sedentary and trained men.

Glomerular Filtration Rate and Albumin Excretion After Maximal Exercise in Aging Sedentary and Active Men

BACKGROUND

From 30 years onwards there is a linear reduction of renal function of about 0.41% per year. Aging induces progressive impairment of glomeruli leading to an increase in protein excretion. The purpose of the present study was to investigate the effect of maximal exercise on glomerular filtration rate (GFR) and albumin excretion in an aging population.

METHODS

This is a cross-sectional study from 213 healthy men, sedentary or endurance-trained, aged 20-30 and 50-80 years submitted to maximal exercise on a cycle ergometer. Blood and urine samples were obtained at rest and after the strenuous exercise. We evaluated the GFR by measuring creatinine clearance and the urine albumin excretion rate.

RESULTS

After exercise, the older adults had a lesser reduction in GFR (mean 12%) than the young participants (mean 28%). As compared to those at rest, the increase of postexercise albumin excretion rates was lower in older participants (mean 7-fold) versus the young population (mean 20-fold). It appears that the exercise impact on some renal functions is related to the absolute load imposed on the individuals (r2 = 0.693).

CONCLUSION

As far as GFR and urine albumin excretion are concerned, regular endurance training does not induce any signs of potential incipient nephropathy in a healthy aging population.

Hyperlipidaemia, lack of sleep and smoking as risk factors for proteinuria among high altitude mountain trekkers

AIM

The number of alpine accidents has been increasing among trekkers in Japan. Some of the alpine accidents have been related to acute mountain sickness (AMS). At present, the mechanism of AMS is poorly clarified, however, it is well known that hypoxia at high altitudes plays an important role. A good relation exists between proteinuria, altitude and hypoxia. However, no reports are available concerned with the risk factors of proteinuria for trekkers at high altitudes.

METHODS

The authors evaluated 41 trekkers and 13 highlanders (cabin employees) through physical examinations and interviews held in a mountain cabin (2300 m above sea level) located in a mountain (2926 m above sea level) in the Japanese Alps. First, urine samples were collected and urinalysis was performed. Second, non-invasive blood pressure, heart rate, and arterial oxygen saturation (SpO2) were measured using a portable life monitor.

RESULTS

Proteinuria was present in 20 (49%) participants. Past history of hyperlipidaemia, amount of sleep, and smoking history are independently associated with proteinuria. Among the physiological examinations conducted at the cabin, only systolic blood pressure demonstrated strong association with proteinuria. Receiver operating characteristic curve analysis using a score combining past history of hyperlipidaemia, amount of sleep and smoking history revealed that the diagnostic accuracy of proteinuria at the cut-off score of 2 was 80%.

CONCLUSIONS

This study indicated that these three variables were significantly and independently correlated with proteinuria: hyperlipidaemia, amount of sleep (night before) and smoking history. Improvement of these three variables might decrease the risk of alpine accidents including AMS.

The effect of reactive oxidant generation in acute exercise-induced proteinuria in trained and untrained rats

Exercise-induced proteinuria is a common consequence of physical activity, although its mechanism is not clear. We investigated whether free radicals generated during exercise play a role in post-exercise proteinuria in sedentary and treadmill-running trained rats, separately. Sedentary and trained rats were randomly divided into four sub-groups: control, antioxidant treatment, exhaustive exercise and an exhaustive exercise plus antioxidant treatment group. Antioxidant therapy was applied by intragastric catheter for 4 weeks with vitamin C (ascorbic acid, 50 mg x kg(-1) x day(-1)) and vitamin E (alpha-tocopherol, 20 mg x kg(-1).day(-1)). Twenty-four-hour urine samples were used for measuring protein levels and protein electrophoresis. Thiobarbituric acid (TBARS) and glutathione (GSH) levels, superoxide dismutase (SOD) and catalase (CAT) activities were assayed in blood and tissues. Increased urinary protein levels and mixed type proteinuria in electrophoresis were identified after exhaustive exercise in sedentary rats. Erythrocyte, kidney and muscle TBARS levels were significantly elevated in this group. Antioxidant treatment prevented the increase in urinary protein levels, TBARS levels and the occurrence of mixed type proteinuria after exhaustive exercise in sedentary rats. Exhaustive exercise in trained rats resulted in elevation of urine protein levels and mixed type proteinuria although kidney TBARS levels were not changed compared to those of the trained controls. Antioxidant therapy in trained and exhausted-trained animals resulted in decreased TBARS levels in the kidney but it did not affect urinary-increased protein levels or electrophoresis in exhausted animals. This findings suggest that the exercise-induced oxidant stress may contribute to post-exercise proteinuria in sedentary rats. However, this mechanism may not be responsible for proteinuria in trained rats.

Lisinopril reduces postexercise albuminuria more effectively than atenolol in primary hypertension

Physical exercise causes transient albuminuria. The mechanisms of postexercise albuminuria are not fully clarified but stimulation of the reninangiotensin system (RAS) probably plays a major role through intrarenal haemodynamic changes causing an elevated filtration pressure. In a randomised, double-blind, crossover study we compared the effects on urinary albumin excretion (UAE) of lisinopril (L) and atenolol (A) therapy, i.e. we aimed to investigate whether inhibition of the RAS or inhibition of beta1-adrenoceptor-mediated effects of the sympathetic nervous system differed with regard to changes in UAE. Sixteen patients with uncomplicated primary hypertension were studied. Four standardised bicycle ergometer exercise tests were performed, before and after each active treatment period. UAE 30 min postexercise, determined by radioimmunoassay, was significantly lowered by both treatments: -278 mu g center dot min-1 (L) and -199 mu g center dot min-1 (A). The reduction of postexercise UAE achieved by treatment with the angiotensin-converting enzyme (ACE) inhibitor (L) was significantly greater than that achieved by the beta1-selective adrenoceptor blocker treatment. Blood pressure (BP) at rest and during exercise were equally reduced by both drugs. In conclusion, this study showed that antihypertensive treatment with an ACE inhibitor was more effective in reducing exercise-induced albuminuria than a beta1-selective adrenoceptor-blocking agent with a similar degree of BP reduction in patients with uncomplicated primary hypertension. This suggests that the RAS plays a major role in postexercise albuminuria in hypertensive subjects. The clinical significance of this finding, however, remains to be clarified.

Protein excretion after prolonged exercise

Random urine samples were obtained from 16 healthy subjects (nine men and seven women) before and after a 100 Km hill walk for the estimation of total protein, albumin, N-acetyl-beta-glucosaminidase (NAG), retinol binding protein (RBP) and creatinine. The excretion of total protein, albumin and NAG (expressed in relation to creatinine excretion) increased significantly after the walk. The relative clearance of protein and albumin also increased. In four subjects serial measurements were made for 4 days and the excretion of albumin and NAG on the fourth day were similar to the pre-walk values. We conclude that proteinuria of prolonged exercise is at least partly due to reduced tubular reabsorption.