The effects of endurance training on athletes’ oral health

By Danielle Dotson and Keri McShan

Abstract

Over the past decade, endurance training increased in popularity in our society. As the popularity of people participating in endurance training increased, the number of research studies increased as well. Endurance training consists of many high intensity exercises such as marathons, swimming, and multiple other sports. The research revealed the correlation between endurance training and the effects that it had on the athlete’s oral health. The biochemical marker, salivary alpha amylase, is a component of saliva that is in relation to catecholamine that increased in response to stressful situations such as intensive exercises that are being done when participating in endurance training. An increase in salivary alpha amylase increased the athletes’ chance of developing negative oral side effects. A few of these included development of dental caries, dental erosion and an increased risk for xerostomia. There are many other components that increased the athlete’s risk of developing negative oral side effects such as their food choices, frequent consumption of sports drinks and the consumption of workout supplements. With the increased number of people participating in endurance training, dental hygienist need to be aware of the risk associated, and be able to provide proper patient care accordingly. Many athletes tend to focus on the overall improvement of their health that they receive by this type of high intensity training, and may disregard, or not be aware of the effects that could occur to their oral health. Many people may also not make the correlation of overall health with oral health. Dental hygienist can play an important role in reducing athletes’ chance of developing negative oral side effects by educating the athletes of their risk, and providing them with ways to prevent these negative side effects. Many studies have revealed that endurance training increases the athletes’ chance of developing dental erosion, xerostomia, and dental caries. The majority of the studies concluded that further studies need to be conducted to fully understand the long term and short term oral effects endurance training has on the athlete.

Keywords: Endurance training, dental erosion, dental caries, salivary alpha amylase.

Endurance training has increased in popularity in the United States. Endurance training involves high- intensity training activities. Examples include marathons, swimming, bicycling, basketball, and gymnastics (Endurance, 2014). Many athletes are consumed by the fact that they are becoming physically fit and fail to realize the negative effects that are taking place in their oral cavity, which effects the overall health of the athletes as well. Saliva plays a critical role in biofilm formation on the surfaces of the teeth. Salivary alpha amylase is a key biochemical marker in the saliva. It is connected to an increase of norepinephrine and epinephrine in relation to stress. Physical stress such as endurance training increases the amount of salivary alpha amylase found in the saliva. This increased the risk of xerostomia, erosion, and dental caries (Levine, Scannapieco, and Torres, 1993). Other components also contributed in negatively effecting the oral cavity of endurance athletes. These components include the increase in frequency of sports drink consumption, the different ingredients in pre workout supplements, and the food choices made during and after training. These factors increased the acidity of the oral cavity and negatively effected the body as a whole. Dental hygienist play a critical role in making the patients aware of the risks of endurance training and providing prevention strategies. Hygienist should educate each patient on what should be implemented to prevent these negative effects (Yan-Fang, 2011). Endurance training increased the athletes’ chance of developing dental erosion, xerostomia, and dental caries.

Endurance training

In today’s society, endurance training has grown more in popularity as exercising became more of a fad. Endurance is one of the main elements of becoming in shape along with an increase in strength and power. Building endurance has been recommended as the key component when improving physical health. Endurance training requires the most effort to develop the necessary physiological changes the body needs to build endurance, and takes the greatest amount of time (Nessel, 2009).

To build endurance, one must have a starting point. This is typically with 10 to 15 minutes at a time, and gradually building up. Elite athletes may train up to two to three hours daily (Endurance, 2014). Endurance exercise involves activities that increase your breathing and heart rate. There are many different types of endurance training such as power walking, running/jogging, dancing, swimming, biking, and playing sports. The types of athletes that have participated in this type of training are marathon runners, triathlon participates, and elite athletes such as competitive swimmers, gymnasts, basketball players, football players, etc. (Endurance, 2014).

The purpose of endurance training when it comes to improving your overall health is to sustain the heart, lungs, and circulatory system in a state of well-being. Endurance training can reduce the risk of developing many diseases such as diabetes, heart disease, and stroke. (Endurance, 2014). Endurance training helps to provide athletes with the ability to train longer rather than faster due to an increase in the size of slow twitch fibers compared to fast twitch fibers (Nessel, 2009). Endurance training also improves oxygen supply by up to 80%, due to an increased formation of the iron containing protein, myoglobin (Nessel, 2009).

Endurance training enhances the ability of the muscle to utilize free fatty acids for energy. With this being done, the body has spared more carbohydrates until the event of training where fueling speed is needed. As a result of six months or more of training, many athletes have reduced resting heart rates by up to twenty beats per minute. (Nessel, 2009). “Several studies have shown that an average of one beat per minute per week is dropped as cardiac conditions improve” (Nessel, 2009, p. 8).

Oral health of endurance athletes

Oral health is a crucial component to one’s overall health, well-being, and quality of life. The oral cavity is linked to systemic health. The connection between oral health and sports has vastly been investigated through studies from oral health to oral trauma (Ashley, 2015). Poor oral health can diminish the quality of life and bring on an inflammatory response, thus reducing the athletic performance. Many athletes do not realize the impact their oral health can have on their quality of life.

As stated by Ashley (2014), “Participating in endurance sports can have an effect on dental erosion, caries prevalence and salivary flow rates…” (p. 1110). A study was conducted by Ashley, Di Iorio, Cole, Tanday, and Needleman that evaluated 34 research articles about the impact of elite training on oral health. From these articles, the authors developed a percentage range of different types of oral effects on the athletes. Sixteen of these studies focused on the prevalence of oral diseases among elite athletes. These studies found that 15-75% had dental caries, 36-85% had dental erosion, and 15% had periodontal diseases. The studies used the indices of DMFT to assess the rate of dental caries. (Ashley, 2015)

Another study was conducted at the 2012 London Olympics evaluating the impact of oral health on the athlete’s performance. The athletes had a full oral examination, and by using a modified shortened global evaluation of the impact of oral health on quality of life to assess the impact of oral health on the performance. All of the responses were scored on a five-point scale.

The study concluded that more than 40% of the athletes were bothered by their oral health. Out of that percentage, 28% reported that it had an impact on the quality of life and 18% on training and performance. Many reported that the impact was significantly associated with carious lesions (Ashley, 2015). The risk of bias of this study was lack of calibration of the 34 studies, and lack of comparison groups within the studies. Without a control group, it is more difficult to determine the portion of risk that is fully associated with endurance training (Ashley, 2015).

Salivary alpha-amylase

“Components of saliva play an important role in the colonization and metabolism of bacteria in the oral cavity” (Levine et al, 1993, p. 301). A biochemical marker in saliva produced during endurance training is salivary alpha amylase. It is one of the most abundant components in human saliva, and has at least three biological functions. (Levine et al, 1993). It plays a role in carbohydrate digestion, binds with high affinity to a selected group of oral streptococci, and binds to teeth as a constituent of the enamel pellicle.

Research completed by Levine et al (1993) stated that, “Alpha amylase… is a calcium containing metalloenzyme that hydrolyses the alpha 1,4 linkages of starch to glucose and maltose. It is a family of proteins, consisting of several isoforms that differ in charge and glycosylation” (p. 301). Salivary alpha amylase is a non-invasive marker of sympathetic nervous system activity and shows a relationship with norepinephrine released throughout exercise (Gobbo, Rodrigues, Silveira, Souza, Possato, Lira, Vuolo, & Zagatto, 2014). The acquired enamel pellicle in dental plaque contains alpha amylase which may serve to promote the adhesion of streptococci, the bacteria known to cause dental caries, to the tooth surface. Salivary alpha amylase is proven to be identified in dental plaque by these methods: immunochemical, enzymatic, and electrophoretic. (Levine et al, 1993).

Salivary alpha amylase undergoes many changes during endurance exercise. The level of salivary alpha amylase increases in response to stress related activities including physical stressors such as treadmill exercise, running, basketball, etc. This reaction is due to increased levels of catecholamines, which are norepinephrine and epinephrine that is released into the blood as a response to stress (Arhakis, Karagiannis, & Kalfas, 2012). A study done by Alikhani, M., Badrian, HR., Karimian, J., and Khozaymeh, F. examined the components of saliva and the changes it undergoes during endurance exercising (2011). The study consisted of 19 volunteers who performed endurance exercises for a fixed time at equal velocities. The study concluded that, “…some factors which are important in the oral and dental health, including cortisol, alpha-amylase and acidity, undergo significant changes during an aerobic endurance exercise” (Alikhani et al., 2011, p. 103). The mean cortisol level, which is directly related to stress, increased from 2.73 ng/mL before exercise to 3.60 ng/mL after the exercise.

During the study, the levels of salivary alpha amylase were evaluated before and after sports activity. The results from this study showed a significant increase from 59.57, to 107.52 IU.mL. The research also revealed that the mean salivary pH decreased from 6.84 to 6.82, thus increasing in acidity (Alikhani et al, 2011). A bias of this theory is that other studies have shown that the increase in salivary alpha-amylase could actually be a positive effect. The studies state that the alpha-amylase could prevent the adherence of biofilm and potentially lead to bacteria clearance from the oral cavity (Levine et al., 1993).

Salivary alpha amylase has a negative effect on the athlete’s oral health as compared to non-endurance athletes due to its increased levels during endurance training. Some of these negative effects include xerostomia, dental erosion, and dental caries. Xerostomia, also known as dry mouth, results from a reduction of salivary flow. A study conducted by Mulic, Sivertsen, Skaare, Songe, & Tveit concluded that during endurance exercise salivary flow was decreased in 64% of the participants in the study (2012).

This change could be linked to an increase in sympathetic nervous system activity during intense exercise. Studies show that since sympathetic innervations cause a marked vasoconstriction; thus, resulting in reduced salivary volume (Mulic et al, 2012). Xerostomia induced endurance training can also be linked as a consequence of sweat induced dehydration and lack of fluid intake throughout the training. Dental caries are also often noticed in endurance athletes. A study conducted by Frese, C., Frese, F., Kuhlman, Reljic, Saure, Staehle, & Wolff resulted in a significant correlation found between the index, DMFT, and the cumulative weekly training time (2014). The study of decayed, missing, or filled tooth due to decay (DMFT) showed a similar caries prevalence of 9.4 in athletes vs. 8.6 in non-athletes. However, weekly training of one hour per week resulted in a raise of the DMFT in value of 0.24 thus resulting in higher caries risk (Frese et al, 2014). The same study showed that there was an increased level of dental erosion in endurance athletes. Dental erosion is the loss of enamel through chemical means. The cumulative BEWE score of the athletes was 9.6 which represented a medium risk level for dental erosion, meanwhile non athletes score was 7.3 which represents a low risk for dental erosion (Frese, 2014). Changes in the components of saliva, including alpha amylase can have a detrimental effect on endurance athlete’s oral health.

Although there was significant research indicating the role salivary alpha-amylase plays in endurance training and the effects on the oral cavity, more research is needed to completely understand the true extent of the role. Many of the studies previously mentioned state the importance of further research of salivary alpha-amylase. More research is also vital to prove or disprove the contraindicating theories of whether increased levels are beneficial or detrimental to the oral cavity.

Other components

In many cases endurance athletes tend to overlook the importance of their oral health as compared to their general health and fitness. The high intensity training of these athletes, high frequency of eating, reduced salivary flow, and less than optimal oral hygiene correspond with increased risk factors for dental caries and erosion (Bryant, Drummond, Mclaughlin, & Morgaine, 2011). Some of the components effecting the oral health of endurance athletes are sports drinks, workout supplements and food choices made during and after training. Endurance athletes often choose foods that are high in fermentable carbohydrates, and acidic sports drinks to meet their high energy demands (Bryant et al., 2011).

The primary purpose of endurance athletes choosing sports drinks is for rehydration and replacement of electrolytes during training. The reason that sports drinks are related to dental erosion is due to the PH being below 5.5, which provides an optimal environment for the demineralization of the enamel (Bryant et al, 2011). A study was conducted involving 304 athletes from Ohio State University to determine the prevalence and the amount of erosion associated with the consumption of sports drinks (Casamassimo, Haye, & Matthew, 2002). Sixty-three percent of the athletes reported that they drank at least one liter of sports drinks daily.

The total prevalence of dental erosion was found in 36.5% of the athletes involved in the study. Of that percentage, erosion involving the enamel was found in 75.2% of these subjects. Erosion was involving the dentin in 8.8%. The results of this study may not be a representation of every university in the United States. One limitation of this study that may prove to be bias is that not all athletes were involved in this study to due schedule limitations (Mathew et al, 2002).

Another component that effects the oral health of endurance athletes is pre-workout supplements. The use of some of these supplements has raised concern for the consumer’s safety. Numerous pre-workout products contain one or more central nervous system stimulants which increases the risk of an adverse event; thus, combining exercise with this factor can impose even more stress on the cardiovascular system. Also, increasing the probability for and worsening the outcome of an adverse event (Eudy, Gordon, Hockaday, Lee, Lee, V., Luu, & Ambrose, 2013). The majority of pre-workout products are a proprietary blend, meaning the containment of a mixture of ingredients. A problem caused by this is that the FDA does not monitor dietary supplement labels to guarantee that precise amounts of all ingredients are listed on the labels.

Some common ingredients found in a majority of pre-workout products are caffeine, methylhexanamine (DMAA, creatine, arginine, beta alanine, taurine, and phosphorus (Eudy et al., 2013). Caffeine is known as a stimulant found in many beverages. The gastrointestinal tract absorbs 99% of the caffeine ingested orally within 45 minutes. Caffeine is used in these products to increase alertness, energy, and mental concentration. Caffeine has potential adverse effects such as: arrhythmias, palpitations, restlessness, anxiety, insomnia, irritability, dizziness, and diuresis (Eudy et al., 2013).

DMAA has similar properties to amphetamine and cause a false-positive results in a urine analysis for amphetamines. Many subjects reported adverse side effects after a one-time use of DMAA which included feelings of coldness, fatigue, and lightheadedness.

Creatine produced by the kidneys and liver is commonly found in pre-workout supplements to serve as an energy source. Creatine has the ability to draw water into the muscle cells producing muscle hypertrophy. Serious side effects related to the kidneys, liver, and gastrointestinal system are largely anecdotal (Eudy et al., 2013).

Arginine is another component of pre-workout supplements are converted by the body into creatine. Some adverse effects of this component are bloating, diarrhea, and abdominal cramping. Beta alanine is used to help increase the ability to buffer protons, thus prolonging fatigue. Paresthesia is the only known adverse side effect (Eudy et al., 2013). Phosphorus plays a critical role in growth and development. This component helps increase storage of ATP. No known adverse side effects are associated with this element. The study emphasizes the need for more research to determine the long-term effects of using pre-workout supplements (Eudy et al., 2013).

The food choices of endurance athletes can cause negative impacts on their oral health. Many athletes tend to choose foods high in carbohydrates. These foods are often picked for their ability to increase the athletes’ energy level. Carbohydrates that are fermentable, aid in bacterial reproduction leading to a more acidic oral PH. The carbohydrates break down into simple sugars such as glucose, fructose, maltose, and lactose. Unlike other foods, carbohydrates break down in the oral cavity as opposed to breaking down in the digestive tract. This increases the athletes’ chance of developing tooth decay (Mouth-Healthy, 2014).

Foods that have the ability to stick to the surfaces of the teeth further increase the chance of reducing the oral PH. An example of this type of food often chosen would be granola bars. Athletes also tend to choose acidic fruits as a snack while working out such as oranges, which contributes to the loss of minerals in the teeth (Mouth-Healthy, 2014).

The role of the dental hygienist

Dental hygienists play an important role when it comes to educating patients on the prevention of oral diseases. Many athletes are unaware of the negative effects that training can have on their oral health. The role as a hygienist is to inform the patients that they are at an increased risk for decay, xerostomia, and erosion. It is important to explain what contributes to these conditions and let them know of behavior modifications to reduce their risk.

The dental hygienist is responsible for aiding the patients with products, techniques, and changes they can make in their daily life to reduce the risks that are associated with endurance training. With pediatric and adolescent patients that are partaking in endurance training, the hygienist should inform the parents of the risk and changes that should be made to prevent oral health problems. Early education is vital to the prevention of the negative effects that can occur as a result from endurance training (Yan-Fang, 2011).

The dental hygienist can identify xerostomia by performing a detailed health history, and an oral examination that may reveal dry and friable oral mucosa, and a dry or fissured tongue. Hygienist should recommend lifestyle changes such as reducing the amount of caffeine, and alcohol containing products. Patients should be advised to drink frequent sips of water, or sugarless drinks. Patients should avoid sticky, or sugary foods. Hygienist can recommend the use of xylitol gums, or prescription strength fluoride to prevent xerostomia from causing negative effects (ADA Science institute, 2016).

Prevention is the most important approach when it comes to caries reduction. A suspicious area can be identified by the clinician through radiographic interpretation and clinical appearance. However, the diagnosis of dental caries must be made by a licensed dentist. If a carious lesion is already present, restorative treatment must be done.

This is why dental hygienist play a major role in providing the patient with education on how to prevent decay. Hygienists can also apply in office topical fluoride treatments such as fluoride varnish, or foams to aid in the prevention of decay. Hygienists can perform a caries management by risk assessment in order to analyze the patient’s risk factors for decay. Recommendations can be made for the use of over the counter fluoride products, and dietary changes that should be made (Azevedo, Lyon, Young, (2010). Some diet modifications that can be easily implied by the patient or parent are to switch to whole grains opposed to refined, eat dark green or orange vegetables, eat a variety of fruits, and choose fish beans or nuts for protein needs. Overall, the patient should try to reduce their amount of sugar from foods or drinks. Encouraging patients to drink fluoride water can also be easily attainable thorough ingestion of tap water (Mouth-Healthy, 2014)

Hygienists should perform an in depth evaluation of the patients’ risk factors for dental erosion. Clinical observation of the tooth surfaces can provide evidence of erosion. The most frequent tooth surfaces affected are the lingual surface of the maxillary incisors and occlusal surfaces of the first molars. Hygienists can aid in the prevention of erosion by explaining the causes to the patient and by providing preventative education.

Hygienists should recommend the avoidance of frequent intake of acidic beverages. If acidic drinks are consumed, they should be during meals and with the use of a straw. Patients can increase the use of at home fluoride products, along with the professional application of fluoride by the hygienist at their dental visits (Yan-Fang, 2011).

Conclusion

In today’s society, many people have participated in endurance training type events. This increase in the number of people partaking in such activates had sparked the increase in the studies pertaining to the negative effects that endurance training has on oral health.The research that was reviewed concluded that endurance athletes are at a greater risk of developing xerostomia, dental caries, and dental erosion as compared to non-endurance athletes.

More studies need to be conducted to provide further information in order to truly understand the short term and long term effects of endurance training. As this has grown more popular in today’s society, hygienists need to be aware of the effects, and how to educate their patients accordingly. It is important for the hygienist to question if their patients are partaking in these activates in order to provide proper care and prevention strategies to hopefully prevent any negative effects from occurring.

Danielle Dotson and Keri McShan are dental hygiene students at Collin College in McKinney, Texas.

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