|Year : 2021 | Volume
| Issue : 2 | Page : 70-74
Effect of left nostril breathing on postexercise recovery time
U Karthika Jyothish, Subhasis Das
Department of Physiology, Pondicherry Institute of Medical Sciences, Puducherry, India
|Date of Submission||26-Oct-2021|
|Date of Acceptance||06-Nov-2021|
|Date of Web Publication||30-Dec-2021|
U Karthika Jyothish
Plot 59, Hollywood Farm Beach, Ganapathichettikulam, Puducherry
Source of Support: None, Conflict of Interest: None
Background: The nasal cycle is the alternating congestion and decongestion of the nostrils during normal breathing, marking the shift between the sympathetic and parasympathetic systems, the latter being prominent when breathing through the left nostril. The post-exercise period is characterized by a gradual shift from sympathetic to parasympathetic dominance. It is hypothesized that breathing only through the left nostril will aid in accelerating this shift in the postexercise period.
Objectives: The objective of this study is to assess the effect of left nostril breathing on post-exercise recovery times of heart rate and blood pressure (BP).
Materials and Methods: A total of 60 young healthy male volunteers were instructed to walk on a flat treadmill, following a fixed protocol. Heart rate and BP were measured at rest and postexercise they were monitored every minute until they reached the baseline. The recovery time was noted. The procedure was the same on the 3rd day, except that during the postexercise period, the participants were instructed to breathe only through their left nostrils.
Results: The recovery times of heart rate and BP, when breathing through the left nostril only, was significantly lower than when breathing normally.
Conclusion: The left nostril breathing technique lowered the postexercise recovery times of cardiovascular parameters, which can be attributed to improved parasympathetic tone. These findings on the post-exercise state may be extrapolated to pathological states of sympathetic dominance, and left nostril breathing can be used as an adjunct to pharmacological therapy to manage such conditions.
Keywords: Left nostril breathing, postexercise, recovery period
|How to cite this article:|
Jyothish U K, Das S. Effect of left nostril breathing on postexercise recovery time. J Curr Res Sci Med 2021;7:70-4
| Introduction|| |
The nasal cycle, an ultradian rhythm lasting approximately for 2–3 h, is characterized by alternating congestion and decongestion of the nostrils due to vasodilatation and vasoconstriction, respectively; and it serves to prevent excessive drying and crusting of the nasal mucosa, thereby fulfilling its functions of humidifying, filtering and warming the inspired air.
During any phase of the nasal cycle, the cerebral hemisphere contralateral to the more patent nostril is more active. It has also been shown that the right cerebral hemisphere has predominantly parasympathetic activity and the left cerebral hemisphere has predominantly sympathetic activity., This would mean that breathing through a single nostril can influence the autonomic function.
Thus, the nasal cycle can effectively serve as a marker of alternating cerebral activity during the wake state. Apart from influencing the autonomic nervous system, the nasal cycle affects many physiological functions such as mood, cognition, blink rate, intraocular pressure, blood glucose levels, reaction time, respiratory rate, heart rate,,,, and blood pressure (BP).,,,,,
Manipulation to alter or voluntarily control the nasal cycle can be done by using maneuvers such as cyclical nostril breathing and forced nostril breathing. Unilateral forced nostril breathing is defined as the technique of breathing selectively through one nostril. This allows us to voluntarily control the cerebral dominance,, and thereby influence the autonomic nervous system.
Tachycardia during relatively mild exercise is due to withdrawal of parasympathetic restraint on the SA node and at higher levels, due to an increase in sympathetic activity. Impulses from higher centers and sensory inputs from mechanoreceptors and chemoreceptors in blood vessels, joints, and muscles also contribute to exercise-induced tachycardia. Systolic BP is always raised during exercise and the change in diastolic pressure depends on the total peripheral vascular resistance and may increase slightly, remain unchanged or even decrease. Consequently, dynamic exercise is often characterized by an increase in the mean arterial pressure. Inputs from the metabo-and mechanoreceptors from the exercising muscles as well as central commands from the higher centers are responsible for an increased sympathetic activity that leads to a rise in BP. Fall in these parameters in the immediate post-exercise period is considered to be due to reactivation of the parasympathetic nervous system with increased vagal activity and therefore a reversal of the state produced by exercise.
Increased vagal activity has been associated with a reduction in the risk of death and therefore it is projected that the rates of recovery of the heart rate and BP immediately after exercise may be an important prognostic marker and they depend on modulations by the autonomic nervous system. The two parameters, namely heart rate and BP recoveries immediately after exercise have independently been shown as predictors of mortality.,,,,
The increase in heart rate and BP in response to exercise can be compared to a pathological state of cardiac dysautonomia characterized by increased sympathetic activity. Therefore, the postexercise period can be likened to a simulated state of tachycardia and accelerated hypertension. Many nonpharmacological methods have been developed and are being used to control hypertension and tachycardia. Apart from lifestyle modifications like reduced salt intake, weight loss, limited alcohol intake, various complementary methods have been proposed for the treatment of essential hypertension, such as biofeedback techniques and relaxation methods.
Unilateral forced nostril breathing is one such intervention investigated in various studies. The long-term effects of forced unilateral nostril breathing have been an area of much research. Immediate effects of left nostril breathing on heart rate and BP on volunteers at rest have also been studied. on normal BP also seen.,, However, there is a paucity of data, in the literature, on the immediate effects of such a maneuver during a state of heightened sympathetic activity.
The present study was conducted with the aim to evaluate the immediate effects of forced left nostril breathing during the postexercise recovery period, with the possibility of further evaluating the breathing maneuver as an alternative nonpharmacological adjunct to therapy in controlling such pathological states.
| Materials and Methods|| |
The study was conducted in a controlled environment in the exercise physiology lab in the Department of Physiology, in our institute. Ethical clearance was obtained from the Institute Ethics Committee before the study was initiated (Reference number-IEC: RC/13/104). Sixty clinically normal male volunteers from among the final year medical students, interns, and post-graduate students of the institute, between 18 and 30 years of age were inducted as participants of the study.
Women were not included in the study as the hormonal changes in the various phases of the menstrual cycle would affect the Autonomic Nervous System. Men above the age of 30 years are more likely to have metabolic disorders which in turn may affect the Autonomic Nervous System, hence their exclusion. Trained athletes and practitioners of yoga and smokers were not included. Those with any mechanical, inflammatory, or infective nasal blockage; any respiratory, cardiovascular, or musculoskeletal disorders; and those using Autonomic Nervous System modifying drugs were excluded from the study.
Each volunteer was instructed to avoid caffeinated beverages and alcohol for at least 12 h before the test. He was also asked not to engage himself in any additional physical exercise for 48 h before the study, and to report to the lab after a light breakfast.
The study was done on 2 days. On the 1st day of the study (day 1), the participant was briefed about the procedure and written informed consent was obtained. After obtaining a detailed history, anthropometric measurements were recorded using a stadiometer and weighing scales. A general physical examination was also done. Subsequently, the participant was made to lie comfortably in the supine position. After 5 min of rest, baseline BP and heart rate were measured (OMRON digital automatic BP monitor. Model M10-IT [HEM-7080IT-E]) in the left upper arm. He was then instructed to walk on a flat treadmill (model AFTON [ACP087]) for 15 min at a constant speed of 6 km/h. Subsequently, BP and heart rate were recorded in the supine position, every minute, till they reached preexercise levels. The time taken for recovery of each of the parameters to return to baseline was noted.
The volunteer was advised to report to the laboratory at the same time, after a day's rest (day 3) following the same instructions that were given initially. After basal BP and heart rate recordings in the supine position, he was asked to repeat the same exercise as on day 1. In the recovery phase, the participant was instructed to occlude his right nostril from the outside with his right index finger and breathe only through his left nostril while his heart rate and BP were monitored in the supine position every minute until it reached pre-exercise levels. The time taken for recovery of the parameters during this breathing maneuver was also noted.
The data were tabulated and analyzed using SPSS 17.0 statistical software for Windows. The Wilcoxon signed-rank test was used for comparison since the paired data were not normally distributed.
| Results|| |
The findings of the study are given in [Table 1], [Table 2], [Table 3], [Table 4].
The heart rate, systolic BP, and diastolic BP at the start of the test on day 1 and day 3 were comparable as the difference between the values on both days were statistically not significant (P > 0.05 in each comparison).
The comparison of postexercise recovery times of heart rate, systolic BP, and diastolic BP on day 1 and on day 3 was done. Since the data was not normally distributed, a nonparametric test was used for comparison. The difference between the median recovery times of the above parameters on day 1 and day 3 was statistically significant (P < 0.001).
| Discussion|| |
This study was a cross-sectional observational study done on 60 clinically normal, nonsmoking male volunteers in the age group of 18–30 years. On the first day (day 1) of the study, after recording the baseline heart rate, systolic and diastolic BPs, the participants walked on a motorized treadmill for 15 min at a speed of 6 km/h. Subsequently, all the three parameters were recorded every minute in the post-exercise period until they reached their respective baseline levels, while the participants were breathing through both nostrils all along. The same procedure was followed on the next day of the study (day 3), except that during the post-exercise recovery period, the volunteers were instructed to occlude their right nostril and breathe only through their left nostril. Statistical analysis of baseline values on day 1 and day 3 of heart rate (74.8 ± 9.59 bpm and 75.83 ± 9.33 bpm, respectively), systolic BP (113.37 ± 9.82 mm Hg and 112.88 ± 9.62 mm Hg, respectively), and diastolic BP (72.85 ± 6.68 mm Hg and 71.88 ± 6.32 mm Hg, respectively) showed that they were comparable (P > 0.05 for each parameter). Thus there were no differences in the mean values of the cardiovascular parameters on the 2 days of the study before the start of the exercise sessions. Similar analyses were done on the cardiovascular parameters immediately after the exercise sessions on the 2 days of the study and were found to be comparable (heart rate − 91.78 ± 14.96 bpm and 91.15 ± 12.03 bpm; systolic BP − 130.05 ± 11.47 mm Hg and 128.18 ± 12.42 mm Hg; diastolic BP − 78.83 ± 7.53 mmHg and 77.52 ± 7.23 mm Hg, respectively, on day 1 and day 3). Thus, it can be inferred that the grade and duration of exercise on the 2 days of the study were similar for each participant since the effects of the exercise sessions on the cardiovascular parameters were found to be similar. Analysis of our results showed a statistically significant reduction in the recovery times of the parameters on day 3 as compared to day 1 (P < 0.001 for each parameter). This difference underlines the activation of the parasympathetic system brought about by forced left nostril breathing.
The effect of forced left nostril breathing on heart rate observed in this study supports the findings of Jain et al. who demonstrated decrements in heart rate in male and female participants following 15 min of left nostril breathing and after 8 weeks of practicing this breathing maneuver. However, the present study demonstrates the immediate effect of left nostril breathing, and not a practiced effect as reported by Jain et al. Shannahoff-Khalsa and Kennedy undertook a series of three different experiments to study the immediate and practiced effects of nostril breathing with varying respiratory rates in healthy men and women. Their study also reported a similar decline in heart rate following left nostril breathing. In the study done by Bhavnani et al., immediate decrease in heart rate was observed in hypertensives after 27 rounds of forced left nostril breathing. On the contrary, in a study done by Dane et al., both left and right nostril breathing increased heart rate in right-handed male subjects. The BP changes observed in our study also uphold the findings of Jain et al. who demonstrated a fall in systolic and diastolic BPs after left nostril breathing for 15 min. Reduction in systolic and mean pressure after left nostril breathing was also demonstrated by studies done by Raghuraj and Telles. Twenty-seven rounds of left nostril breathing resulted in an immediate reduction in systolic BP in hypertensive male participants in the study done by Bhavnani et al. On the other hand, in the study done by Dane et al. on 88 male and 41 female volunteers, unilateral forced right as well as left nostril breathing increased the systolic BP without a change in diastolic pressure in men. However, in women, left nostril breathing decreased systolic and diastolic BPs.
To the best of our knowledge, and as far as our literature search revealed, a study on the immediate effects of left nostril breathing on a simulated state of sympathetic over-activity characterized by an increase in heart rate and BP has not been reported so far. The results of our study put forward evidence for the predominantly parasympathetic effect of left nostril breathing in such a simulated state. The earlier observations that the left nostril patency causes increased activity in the right cerebral hemisphere and the right cerebral hemisphere is found to have predominantly parasympathetic activity,, may be used to explain these findings, even though till date no well-defined anatomical pathway connecting the nostrils and the autonomic centers has been reported. It would be relevant to find out the reproducibility of the results obtained in individuals of other age groups. It would also be interesting to see if these effects change with the phases of the menstrual cycle in women. Moreover, the effect of this maneuver on those with any existing dysautonomia has to be evaluated, as our study included only clinically normal volunteers. If found effective in the above-mentioned conditions also, left nostril breathing can be developed into a nonpharmacological adjunct to therapy in conditions such as supraventricular tachycardia and accelerated hypertension, which can be deemed to be equivalent to the increased heart rate and BP seen with exercise.
| Conclusion|| |
This observational study done on 60 young healthy male volunteers, who were neither trained athletes nor practitioners of yoga, was taken up with the hypothesis that forced left nostril breathing would shorten the postexercise recovery time by improving the parasympathetic tone. The results showed a statistically significant decrease in the recovery times of heart rate, systolic BP, and diastolic BP when the participants practiced left nostril breathing in the post-exercise period, thus supporting our hypothesis. It has previously been shown that practice of such a breathing maneuver over a period of time gradually leads to a decrease in heart rate and BP. From the results of this study, it may be concluded that left nostril breathing is effective, even after a single session of the maneuver and has an immediate effect, in reducing an elevated heart rate and BP faster than when not practicing the breathing maneuver, in healthy young men.
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[Table 1], [Table 2], [Table 3], [Table 4]