Immediate Effects of Cooling Pranayama on Salivary pH and Intraoral Temperature in Healthy Individuals: A Single-Arm Pilot Interventional Study

Introduction

Saliva is important in the maintenance of homeostasis as it is a lubricant, buffer to acids produced by bacteria, protector of the teeth and gums from bacteria and other micro-organisms, and supporter of the mineralization of the teeth. For saliva, the optimal pH level should be from about 6.2 to 7.5[1,2]. At a neutral pH, saliva creates an environment that promotes the growth of the oral microbiome, which helps to maintain good oral health and prevent dental caries [2,3]. Conversely, a more acidic environment creates conditions that promote the growth of bacteria and increase the risk of developing gum disease, and also losing tooth enamel [4].

The temperature inside the mouth is also a significant factor in both microbial growth and enzymatic function, as well as oral tissue metabolism. The temperature of the mouth may change in response to temperature changes in the body, and therefore affects a healthy person's mouth [5,6].

Yoga and Pranayama have become popular methods of achieving both physical and psychological health [7,8]. Pranayama is an umbrella term that refers to the various techniques of controlling the breath and regulating the autonomic nervous system that are utilized within different forms of yoga [8,9]. Some of these techniques for cooling down the body are regarded as being effective at helping to cool, relax, and return to a state of homeostasis (balance of emotional, physical, and mental states) [10].

Two types of yogic breathing techniques, Sheetali and Sheetkari, produce a cooling effect in the body; however, there has been little research on how these techniques affect immediate physiological parameters of the mouth (salivary pH) and mouth temperature (intraoral temperature) [11].

Previous studies have provided evidence that cooling yogic breath practices regulate blood pressure and affect the body through two mechanisms (temperature and mood), and improve cognitive function [12,13].

Hereby, no studies have been done to assess the immediate effect of pranayama on salivary pH and intraoral temperature. This pilot study explores the immediate impact of yogic cooling breathing on individuals' physiology using measures of salivary pH and intraoral temperature.

Materials and Methods

Study Design

This study was a single-arm pilot interventional study conducted at SDM College of Naturopathy and Yogic Sciences, Ujire, Karnataka, India.

Participants

A total of 60 individuals were screened, among whom 30 healthy participants fulfilling the eligibility criteria were enrolled and shown in Figure 1.

Inclusion Criteria

• Individuals aged 18–50 years

• Both male and female participants

• Apparently healthy individuals without chronic systemic illnesses

• Participants willing to participate in the study

Exclusion Criteria

• Presence of systemic illness, oral infections, or recent dental procedures

• History of trauma or surgery affecting oral health

• Individuals undergoing other complementary therapies

Ethical Considerations

The study protocol was approved by the SDM Institutional Ethics Committee (EC-760). All participants provided written informed consent before participation.

Sample Size

Sample size was estimated on the basis of a paired design assuming a moderate effect size (d = 0.5), α = 0.05, and 80% power with a minimum requirement of 27 participants. Thirty participants were recruited to allow for attrition.

Intervention

Participants were instructed to avoid eating, drinking, or performing oral hygiene for at least 1 hour prior. They were advised to practice cooling Pranayama techniques like Sheetali and Sheetkari for 20 minutes in a well-ventilated room. For Sheetali Pranayama, the individuals sat in a comfortable meditation posture with the tongue rolled into a tube and protruding out. Inhale slowly and deeply through the curled tongue. Exhale in a controlled fashion through the nostrils. The practice was maintained for some 10 minutes. Then Sheetkari Pranayama was done in a comfortable seated position. In this, participants approximated the teeth gently with the tongue touching the palate. Inhaling was done through the teeth, making a faint hissing sound, then a slow exhale through the nostrils. This pranayama was carried out for about 10 minutes.

Outcome Measures

Salivary pH

Unstimulated whole saliva was assessed using pH indicator strips placed sublingually. Color changes were compared against standardized reference scales.

Intraoral Temperature

Intraoral temperature was measured from the sublingual region using a calibrated digital oral thermometer before and immediately after intervention.

Statistical Analysis

Data were analyzed using IBM SPSS Statistics version 21.0. Normality was assessed using the Shapiro–Wilk test. Since the data followed a normal distribution, a paired t-test was used to compare pre- and post-intervention values. Statistical significance was considered at p < 0.05.

Results

Participant Characteristics

Thirty healthy participants completed the study. The sample consisted of 10 males and 20 females with a mean age of 25.7 ± 12.5 years, as shown in Table 1.

Changes in Salivary pH

Cooling pranayama produced a statistically significant increase in salivary pH. The mean pre-intervention salivary pH was 7.56 ± 1.22, which increased to 7.90 ± 0.88 following intervention. The mean difference was 0.33 with a p-value of 0.02 and is shown in Table 2.

Changes in Intraoral Temperature

A modest but statistically significant reduction in intraoral temperature was observed after pranayama practice. Mean intraoral temperature reduced from 95.82 ± 1.35°F to 95.55 ± 1.38°F. The mean difference was −0.27°F with a p-value of 0.04 and is shown in Table 2.

Discussion

In the current study, we explored the effect that cooling pranayama had immediately after a session on salivary pH and also on intraoral temperature in healthy people. The results of this study showed that a single 20-minute session of Sheetali and Sheetkari pranayama significantly increased salivary pH and decreased intraoral temperature.

Salivary pH plays an important role in the determination of oral microbial ecology and dental health. Acidic environments in the mouth are favourable for the growth of acid-producing (acidogenic) and acid-stable (aciduric) organisms that are known to cause dental caries and periodontal disease [14]. Therefore, a change from acidity towards alkalinity suggests that the mouth may be a more hospitable place for healthy teeth and whole-body wellness (i.e., oral-systemic health) [15,16].

In this study, increased salivary pH is consistent with previous studies documenting the positive effects of yogic breathing exercises on various physiological parameters of the mouth and markers of oxidative stress [17]. Pranayama may help regulate pH by stimulating the secretion of saliva through increased activation of the parasympathetic nervous system [17,18].

The decrease in intraoral temperature observed in this study could be attributed to the cooling airflow produced by working with the Sheetali and Sheetkari pranayama techniques. Using the curled tongue or biting on the clenched teeth during inhalation will allow the air to cool through evaporation while it travels through the oral cavity, therefore reducing the temperature of the oral cavity temporarily(19). Autonomic modulation, particularly the inhibition of the sympathetic nervous system, may also enhance metabolic regulation of thermoregulatory and cognitive functions [20].

Performing Sheetali and Sheetkari pranayama is recommended in yogic texts of olden days. These two types of pranayama are said to help body temperature regulation by stimulating the Vagus nerve and triggering vasodilation, allowing the body to release excess heat [21,22]. That also induces parasympathetic activity via the baroreceptor reflex and leads to sympathetic inhibition [21]. This may be the possible mechanism for the sudden reduction in oral temperature and salivary pH improvement [23]. The physiological data of this study provide preliminary evidence for traditional beliefs regarding these two forms of pranayama [24,25]. Moreover, the participants tolerated the intervention well, and no side effects were noted. Pranayama is an inexpensive, simple, and non-invasive adjunctive strategy that can be used for oral health.

However, despite the advantages of the present study, there are some limitations. The study had a very small sample size, no control group, and only assessed the immediate effects of the intervention. There was also a compromise on the measurement of the salivary pH, as the indicator strips were used rather than the digital pH measurement techniques, which could affect the accuracy of the measurement.

Future studies should include larger randomized controlled trials, longer follow-up periods, and more biomarker assessments, including salivary flow rate, antioxidant levels, pro-inflammatory cytokine levels, and microbial analyses of the oral cavity.

Conclusions

The results of this pilot study indicate that Sheetali and Sheetkari pranayama created immediate favorable results in salivary pH balance and oral temperature reduction immediately after the practice. Additionally, this study suggested that the practice of these yogic breathing techniques may aid in oral homeostasis by promoting an alkaline-based oral environment and lower mouth temperature. It is a virtually no-cost, simple, safe, and effective ancillary method of practicing Oral health promotion. It is warranted that there should be further well-designed studies using random control design to substantiate these findings.

Declarations

Author Contributions

All authors contributed to the study conception and design. PH-Conceptualization, Methodology, Data Collection, Statistical Analysis, Manuscript Preparation; MG-Conceptualization, Supervision, Manuscript Review and Editing; AVR-Methodology, Manuscript Review and Editing. All authors read and approved the final manuscript.

Conflict of Interest

The authors declare no conflict of interest.

Funding

No external funding was received for this study.

Ethical Approval

The study was approved by the Institutional Ethics Committee of SDM College of Naturopathy and Yogic Sciences, Ujire.

Informed Consent

Written informed consent was obtained from all participants before participation in the study.