Effect of Exercise and Fluid Consumption on Salivary Flow and pH

Abstract

Recent claims have been made regarding the putative erosive effects of regularly ingesting low-pH beverages on the integrity of tooth enamel. The purpose of this study was to determine whether fluid consumption during exercise affects the body's defenses against enamel erosion: saliva flow and salivary pH. Males and females (n = 50) exercised in the heat (26.7 °C, 40 % RH) for 75 min on four occasions. Within each session, subjects consumed ad-lib either water, a sports drink (Gatorade®), diluted orange juice, or a homemade sports drink, with the latter three fluids all having low pH values (3.0 to 4.0). Prior to and following exercise, subjects performed a standard stimulated saliva collection procedure. Immediately following collection, saliva flow rate and pH were determined for each sample. Repeated-measures ANOVA were used to evaluate the data. Compared to pre-exercise salivary flow rates (2.6 ± 0.8 ml/min), the post-exercise rate was not different when consuming the sports drink (2.6 ± 0.9 ml/min), but decreased when water or the homemade sports drink was ingested (2.4 ± 0.9 ml/min; p < 0.05). A time-by-drink interaction (p < 0.05) revealed slight differences in saliva pH after exercise, depending on the beverage consumed; post-exercise saliva pH was highest for water (7.2 ± 0.2) and lowest for the homemade sports drink (7.1 ± 0.2), with the sports drink and diluted orange juice values falling in between. The results suggest that minimal changes occur in saliva pH and the rate of stimulated saliva flow with beverage consumption during exercise. Subsequent research is needed to determine whether maintenance of saliva production by drinking beverages during exercise influences the body's defenses against dental erosion via saliva production.

Key words

Dehydration - oral hygiene - sports dentistry - teeth - dental erosion

References

• 1 Amaechi B T, Higham S M, Milosevic A, Edgar W M. Thickness of acquired salivary pellicle as the determinant of the sites of dental erosion.  Caries Res. 1998;  32 311
• 2 Bartlett D W. The causes of dental erosion.  Oral Dis. 1997;  3 209-211
• 3 Ben-Aryeh H, Roll N, Lahav M, Dlin R, Hanne-Paparo N, Szargel R, Shein-Orr C, Laufer D. Effect of exercise on salivary composition and cortisol in serum and saliva in man.  J Dent Res. 1989;  68 1495-1497
• 4 Bishop N C, Blannin A K, Armstrong E, Rickman M, Gleeson M. Carbohydrate and fluid intake affect the saliva flow rate and IgA response to cycling.  Med Sci Sports Exerc. 2000;  32 2046-2051
• 5 Blannin A K, Robson P J, Walsh N P, Clark A M, Glennon L, Gleeson M. The effect of exercising to exhaustion at different intensities on saliva immunoglobulin A, protein and electrolyte secretion.  Intern J Sports Med. 1998;  19 547-552
• 6 Centerwall B S, Armstrong C W, Funkhouser G S, Elzay R P. Erosion of dental enamel among competitive swimmers at a gas-chlorinated swimming pool.  Am J Epidemiol. 1986;  123 641-647
• 7 Dawes C. Clearance of substances from oral cavity - implications for oral health. Edgar WM, O'Mullane DM Saliva and Oral Health. London; British Dental Assoc 1996: 67-80
• 8 Dawes C. Factors influencing salivary flow rate and composition. Edgar WM, O'Mullane DM Saliva and Oral Health. London; British Dental Assoc 1996: 27-42
• 9 Dawes C. The effects of exercise on protein and electrolyte secretion in parotid saliva.  J Physiol. 1998;  320 139-148
• 10 Edwards M, Creanor S L, Foye R H. An investigation into salivary pH changes when exposed to various soft drinks.  Caries Res. 1999;  33 327
• 11 FDI Working Group 10 . Saliva: its role in health and disease.  Intern Dent J. 1992;  42 291-304
• 12 Ford J A, Trevatt N, Dix C A, Fallowfield J L. The effect of fluid replacement and heat on salivary flow rate and optical density at 280 nm in response to exercise.  J Sport Sci. 1997;  15 49-50
• 13 Hannig M, Banister E W. Influence of in vivo formed salivary pellicle on enamel erosion.  Caries Res. 1999;  33 372-379
• 14 Mathew T, Casamassimo P S, Hayes J R. Relationship between sports drinks and dental erosion in 304 university athletes in Columbus, Ohio, USA.  Caries Res. 2002;  36 281-287
• 15 Milosevic A. Sports drinks hazard to teeth.  Br J Sports Med. 1997;  31 28-30
• 16 Moss S J. Dental erosion.  International Dent J. 1998;  48 528-539
• 17 Passe D H, Horn M, Stofan J, Murray R. Palatability and voluntary intake of sports beverages, diluted fruit juice, and water during exercise.  Intern J Sport Nutr Exerc Metabolism. 2004;  14 272-284
• 18 Savad E N. Enamel erosion multiple cases with a common cause (?).  Journal of New Jersey Dent Assoc. 1982;  53 32-37
• 19 Shannon I L, Chauncey H H. Hyperhydration and parotid flow in man.  J Dent Res. 1967;  46 1028-1031
• 20 Ship J A, Fischer D J. The relationship between dehydration and parotid salivary gland function in young and older healthy adults.  J Gerontol. 1997;  52 310-319
• 21 Sirimaharaj V, Brearley Messer L, Morgan M V. Acidic diet and dental erosion among athletes.  Aust Dent J. 2002;  47 228-236
• 22 Venables M C, Shaw L, Jeukendrup A E. et al . Erosive effect of a new sports drink on dental enamel during exercise.  Med Sci Sports Exerc. 2005;  37 39-44
• 23 von Fraunhofer J A, Rogers M M. Effects of sports drinks and other beverages on dental enamel.  General Dentistry. 2005;  53 28-31
• 24 Walsh N P, Montague J C, Callow N, Rowlands A V. Saliva flow rate, total protein concentration and osmolality as potential markers whole body hydration status during progressive acute dehydration in humans.  Arch Oral Biol. 2004;  49 149-154