246 Salivary electrolyte turnover in mid-distance trained sled dogs during 12 weeks of incremental conditioning

Regular exercise improves the health status of dogs; however, extreme exertion in the absence of adequate fluid and electrolyte replacement may decrease performance due to dehydration and cardiovascular stress. Unlike humans and horses, exercising dogs thermoregulate predominantly through respiratory and salivary losses, yet there is limited literature defining changes due to exercise in canine salivary electrolytes. The objective was to investigate the effects of a stepwise exercise regimen on salivary electrolyte concentrations in sled dogs. A training regimen was implemented whereby exercise intensity and duration increased incrementally over 12 weeks and was only altered due to inclement weather. Using sterile gauze and forceps, saliva samples were collected from 16 client owned Siberian Huskies at week-0 (pre-run, post-5.7km-run), week-6 (pre-run, 5.7km, post-39km-run), week-12 (pre-run, 5.7km, post-39km-run). Samples were analyzed for sodium, chloride, potassium, calcium, magnesium, and phosphorous using photometric and indirect ion-selective electrode analysis. Data were analyzed using PROC MIXED of SAS (v.9.4; SAS Institute Inc., Cary, NC). Means were separated using the Tukey adjustment. When compared across weeks, sodium, chloride, potassium, and calcium did not differ at any sampling time point. Throughout the 12 weeks, pre-run and 5.7km phosphorus, and 5.7 and 39km magnesium had increased (P < 0.05). Data were then pooled to evaluate changes due to run distance. Pre-run calcium and phosphorus was higher than at 5.7 and 39km (P < 0.05). Magnesium at 39km was greater than 5.7km, and at 5.7km was greater than pre-run (P < 0.05). Pre-run sodium was lower than at 5.7 and 39km (P < 0.05). Chloride at 5.7km was similar to pre-run and 39km, and at 39km was greater than pre-run (P < 0.05). These data suggest that as dogs become conditioned, they do not employ mechanisms to conserve salivary electrolytes, and that an electrolyte supplement with magnesium, sodium and chloride could be beneficial for sporting dogs.

Differential Associations for Salivary Sodium, Potassium, Calcium, and Phosphate Levels with Carotid Intima Media Thickness, Heart Rate, and Arterial Stiffness

Salivary biomarkers may offer a noninvasive and easy sampling alternative in cardiovascular risk evaluation. The aim of the present study was to establish associations of salivary potassium, sodium, calcium, and phosphate levels with the cardiovascular phenotype determined by carotid ultrasound and carotid-femoral pulse wave velocity and to identify possible covariates for these associations. N=241 samples of nonstimulated whole buccal saliva were obtained from subjects with (n=143; 59%) or without (n=98; 41%) hypertension. The potassium concentrations were 10-fold higher in saliva compared with plasma, whereas sodium concentrations exhibited the reverse relation between saliva and blood. There were no significant correlations between the levels of sodium, potassium, or calcium in saliva and plasma. All salivary electrolytes, except sodium, were significantly associated with age. In age-adjusted analyses, salivary potassium was significantly associated with carotid artery intima media thickness (cIMT) and carotid-femoral pulse wave velocity, and these associations were at the limit of significance in multivariate analyses including prevalent cardiovascular disease and risk factors. Body mass index was a significant confounder for salivary potassium. Salivary phosphate was significantly associated with cIMT in the multivariate analysis. Salivary potassium, calcium, and phosphate levels were significantly associated with heart rate in the univariate age-adjusted as well as in two different multivariate models, whereas no significant associations between sodium and heart rate were observed. In conclusion, the differential association of salivary electrolytes with cardiovascular phenotypes indicates that these electrolytes should be further studied for their predictive value as noninvasive biomarkers for cardiovascular risk evaluation.

Effect of Age on Flow-Rate, Protein and Electrolyte Composition of Stimulated Whole Saliva in Healthy, Non-Smoking Women

As relatively little is known about the effect of age on salivary electrolytes we studied the composition of saliva as function of age to provide reference values for healthy non-smoking women. All non-medicated and non-smoking 30-59-year-old subjects (n=255) selected from among 1030 women participating in a screening program formed the material of the present study. Salivary calcium, inorganic phosphate, magnesium, sodium, potassium, protein and flow-rate of stimulated whole saliva were measured. We found age-related changes in salivary calcium and phosphate concentrations (p=0.001 and p=0.004, respectively, one-way ANOVA). Peak values occurred at around 50-54 years of age. Age had no effect on flow-rate, magnesium, sodium, potassium or proteins. The concentration of sodium correlated positively, while phosphate, potassium, magnesium and protein correlated negatively with the salivary flow-rate. Calcium was the only electrolyte which had no association with flow-rate. Our study provides reference values for salivary electrolytes of 30-59-year-old women.