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 Table of Contents  
Year : 2022  |  Volume : 11  |  Issue : 3  |  Page : 219-223

Effectiveness of crocodile breathing versus prone position in patients with COVID-19: A pilot study

1 Physiotherapy School and Centre, TN Medical College and BYL Nair Ch Hospital, Mumbai, Maharashtra, India
2 Topiwala National Medical College and B. Y. L. Nair Ch. Hospital, Mumbai, Maharashtra, India

Date of Submission02-Jan-2022
Date of Decision19-Feb-2022
Date of Acceptance06-Apr-2022
Date of Web Publication28-Jul-2022

Correspondence Address:
Dr. Madhura Rajesh Patil
Physiotherapy School and Centre, TN Medical College and BYL Nair Ch Hospital, Mumbai - 400 008, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijrc.ijrc_2_22

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Introduction: Physiotherapy and medical management have shown to be beneficial in managing COVID-19 patients. Prone positioning was maximally used in managing these patients, which helped improve ventilation. Crocodile breathing emphasizes diaphragmatic recruitment, decreases accessory muscle use, and triggers the body's relaxation response. The study aims to see the immediate effect of crocodile breathing versus prone positioning in COVID-19. Methods: Thirty participants who passed the eligibility criteria were randomly assigned into two groups. Group A was asked to perform standard of care treatment followed by prone positioning, and after a washout period of a day, they were made to perform standard of care treatment followed by crocodile breathing. Group B performed crocodile breathing on Day 1 and prone positioning on the next day. Outcome measures pulse rate, respiratory rate, rate of perceived exertion, oxygen saturation, single-breath count (SBC), and chest expansion. The patient's feedback was recorded immediately within 1 min pre and post-treatment on both days. Results: Significant improvement was seen in physiological parameters (P < 0.0001), chest expansion (P < 0.0001), and SBC (P < 0.0001) in both groups. However, crocodile breathing was seen to be more effective than prone positioning on SBC (P < 0.0001), rate of perceived exertion (P = 0.000), and chest expansion (P < 0.0001). Twenty-six out of 30 (86%) participants reported crocodile breathing was a more comfortable and better position to relieve dyspnea. Conclusion: Crocodile breathing effectively manages COVID-19 and can be safely incorporated into physiotherapy management for patients with COVID-19.

Keywords: COVID-19, crocodile breathing, physiotherapy, prone positioning

How to cite this article:
Verma CV, Jere GS, Patil MR, Sheth RD, Bharmal RN. Effectiveness of crocodile breathing versus prone position in patients with COVID-19: A pilot study. Indian J Respir Care 2022;11:219-23

How to cite this URL:
Verma CV, Jere GS, Patil MR, Sheth RD, Bharmal RN. Effectiveness of crocodile breathing versus prone position in patients with COVID-19: A pilot study. Indian J Respir Care [serial online] 2022 [cited 2022 Aug 11];11:219-23. Available from: http://www.ijrc.in/text.asp?2022/11/3/219/352640

  Introduction Top

COVID-19, causigured by SARS-CoV-2, has triggered a global pandemic. The unknown pathogenicity of this disease has led to continuous, rapid research participation and engagement of the scientific community.[1] Initially, the Chinese Centre for Disease Control declared that the majority of the cases were mild (81%), being asymptomatic or majorly with nonpulmonary symptoms. The other 14% progress in developing pneumonia, and 5% develop acute respiratory distress syndrome (ARDS) and need intensive care.[2] Signs and symptoms of COVID-19 are classified as asymptomatic; mild (fever, fatigue, breathlessness, sore throat, runny nose, myalgia, expectoration, loss of smell or taste, and digestive symptoms), moderate (pneumonia without hypoxemia), and severe (pneumonia with hypoxemia, SPO2 <92% and critical ARDS, shock, encephalopathy, cardiac injury, heart failure, coagulation dysfunction, and renal injury).[3] The pathophysiological mechanisms in mild-to-severe disease progression remain uncertain, requiring further investigation to formulate therapeutic decisions. Physiotherapy treatment has been proven to be an efficient adjunct to medical management in COVID-19 patients. It consists of relaxation, breathing exercises, airway clearance maneuvers, body positioning, mobility, strength, and aerobic training.[4],[5],[6] Body positioning directly affects oxygen transport and is a noninvasive physiotherapy intervention that improves arterial oxygenation. It helps to postpone, reduce, or avoid invasive, mechanical, and pharmacological forms of respiratory support. Prone position improves ventilation by altering ventilation-perfusion mismatch, reducing physiological shunt, increasing lung volume, and recruitment of dorsal lung regions. It prevents atelectasis and secretion clearance and causes a beneficial fluid shift.[7] Breathlessness is the primary symptom of COVID-19; patients were majorly found to be apical breathers with excessive accessory muscles. Apical breathing causes the structure to tilt back with every breath, limiting mobility in the thoracic spine.

Crocodile breathing involves recruitment of the diaphragm in the prone position, increasing pelvic control, encouraging proper sequencing, and activation of core muscles which causes stabilization of the shoulder girdle, allowing the lower rib cage to expand.[8] It causes diaphragmatic recruitment, which triggers the body's relaxation response, improves oxygen saturation and resolution of atelectasis, and lowers anxiety and eupnea. Yong Ho Cho et al. (2019) observed that crocodile breathing was beneficial in managing musculoskeletal conditions such as lower back pain and scapular dyskinesia. However, there is a lack of literature on the benefits of crocodile breathing in respiratory diseases.[9] Hence, the study aimed to compare the effects of crocodile breathing and prone positioning on physiological parameters in COVID-19 patients.

  Subjects and Methods Top

A Quasi-controlled crossover experimental pilot study was conducted at a dedicated COVID tertiary care hospital in Mumbai after seeking approval from the institutional ethics committee and registration in Clinical Trial Registry – India (CTRI-REF/2021/01/040164). A total of 30 inpatients met the eligibility criteria, as shown in [Figure 1]. Pregnant, obese, and those on rebreathing masks and invasive and noninvasive ventilator support were excluded as prone to lying are uncomfortable due to abdominal bulk and oxygenation tubes, respectively.[10],[11],[12] After explaining the study procedure in detail, written informed consent was taken from the patients. Demographic data were collected, including anthropometric measures, vital parameters, and comorbidities. Patients were randomly assigned into two groups using a chit method. Group A was administered with 15 min of prone positioning on Day 1 and 30 counts of crocodile breathing on Day 2, along with the standard of care treatment. It is inconvenient to perform more than 30 counts of diaphragmatic breathing in prone as it causes fatigue. Hence, the duration of the maneuver was set considering the comfort of the patient and therapeutic effects. Group B was administered with 30 counts of crocodile breathing on Day 1 and 15 min of prone positioning on Day 2, along with the standard of care treatment. Pre- and Posttreatment physiological parameters (pulse rate, respiratory rate, rate of perceived exertion, and oxygen saturation), single breath count (SBC) using a metronome, and chest expansion was measured immediately within 1 min [Figure 2]. An open-ended question regarding the choice of positioning was recorded on the 2nd day in the language preferred by the patient and later transcribed.
Figure 1: Methodology

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Figure 2: Physiotherapy management

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Crocodile breathing patient lies comfortably on abdomen with head in midline resting on both hands. Patients take slow nasal inhalation for 3 s, followed by a brief pause. Slow nasal exhalation for 4–6 s, followed by a longer pause. During the next breath cycle, the chest should expand, filling the “cylinder” of the abdomen. The anterior chest wall and abdomen are stabilized, and upper limbs are stabilized in abduction. During this therapist uses his hand to guide the patient in the lumber movement [Figure 3]. Thus, greater pressure is placed on the posterior and lateral chest wall and pelvis during inspiration, reducing accessory muscle use.[13]
Figure 3: Crocodile breathing and prone positioning, Prone positioned the patient lying on the abdomen with his head turned to one side. Legs are relaxed, toes face outward, and arms are placed on the sides

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Outcome measures


  1. Pulse rate, respiratory rate, rate of perceived exertion, and oxygen saturation
  2. SBC: This measurement is based on how far an individual can count with a normal speaking voice after one maximal inhalation effort. The count is synced with a metronome at 2 bps[14]
  3. Chest expansion: Using a measuring tape, chest expansion is measured at nipple level during the end of deep inspiration and expiration. Normally, a 2–5” of chest expansion can be observed.[15]


  1. Patient's feedback: On Day 2, the patient's feedback about the comfort and preference for both positions were recorded and later transcribed.

Data analysis

Data analysis was done using SPSS Version 16 (IBM, Chicago, Illinois, USA). Physiological parameters (pulse rate, respiratory rate, rate of perceived exertion and oxygen saturation, SBC, and chest expansion) were tested for normality. Paired t-test and Wilcoxon ranks test were used depending upon the normality. For the open-ended question, qualitative content analysis was used.

  Results Top

Thirty inpatients within 20–60 years with a mean age of 49.10 ± 7.798 years were included in the study, out of which 21 (70%) were male, and 9 (30%) were female. Based on the severity of COVID-19, 8 (26.6%) patients had mild affection, 150 (50%) had moderate affection, and 7 (23.33%) had severe affection. Patients in the study reported comorbidities in the form of diabetes mellitus 5 (16.66%), hypertension 5 (16.66%), 8 (26.66%) participants reported both diabetes and hypertension, and 12 (40%) reported no comorbidities. Out of 30 patients' modes of oxygen 2 (6.6%) patients were on 2 L of nasal O2, 1 (3.3%) was on 3 L of nasal O2, and 27 (90%) were on room air. Significant improvement was seen in physiological parameters (P < 0.0001), chest expansion (P < 0.0001), and SBC (P < 0.0001) in both groups [Table 1]. Crocodile breathing was found to be more effective than prone positioning on SBC (P < 0.0001), rate of perceived exertion (P = 0.000), and chest expansion (P < 0.0001) [Figure 4]. Patient rated question reported that 26 (86%) participants found crocodile breathing to be a more comfortable position in relieving dyspnea, while 4 (14%) participants preferred prone positioning due to the discomfort and difficulty in performing deep breathing associated with crocodile breathing.
Table 1: Statistical analysis

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Figure 4: Comparison of crocodile breathing and prone position on physiology parameters and single-breath count

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  Discussion Top

Physiotherapy management in adjunct to medical management has shown to improve functional capacity with a favorable effect on oxygen saturation in COVID-19. The increase in saturation occurs due to an increase in breathing capacity. This aids in early weaning from external oxygen dependency and reducing hospital stay. It improves patients' respiratory function, exercise endurance, and physical strength, which inhibits the occurrence of various complications or disuse syndromes. Preventing patients from various physical and psychological disorders can facilitate patients' return to family, work, and society as soon as possible and improve their quality of life.[4],[5],[6]

In many studies, prone positioning, an integral part of CARP protocol, has been shown to positively affect patients with COVID-19. Prone positioning is feasible and may yield improvements in many patients with COVID-19 who are receiving respiratory support. It had also shown great improvement in increasing lung recruitment and improving oxygenation. Prone positioning is one of the most used physiotherapy maneuvers. According to the literature, prone positioning improved respiratory mechanics, pleural pressure gradient, alveolar inflation, and ventilator distribution. This helps to increase lung volume and reduce atelectasis.[16]

Physiotherapists have used diaphragmatic respiration to manage various respiratory conditions. It has been shown to improve respiration, chest expansion, and stress reduction.

Crocodile breathing mainly involves breathing by diaphragmatic activation. When one uses their diaphragm to breathe instead of the more typical “shallow breathing” of the intercostals muscles, greater thoracic mobility is established, and enhanced core muscle activation is enabled. This improves the mobility of the shoulder girdle, increases pelvic control, and encourages proper sequencing in the firing of core muscles for greater trunk stabilization.[9],[13] Crocodile breathing involves taking diaphragmatic breaths while lying face-down, also known as Makarasana in Yoga. Crocodile breathing has been shown to positively affect patients experiencing low back pain and improve shoulder girdle mobility.[8],[9] There is a lack of evidence on whether crocodile breathing improves the functional level of the respiratory system among patients diagnosed with COVID-19.

In the present study, patients were given prone positioning along with the standard of care treatment on Day 1, and on Day 2, they were administered 30 counts of crocodile breathing along with the standard of care treatment. A washout period of 24 h was kept between two interventions to observe their accurate effects. All the patients included in this study were benefited from both interventions (P = 0.001.) On comparing the effect of crocodile breathing and prone positioning on physiological parameters, and the pulmonary function test, it was observed that chest expansion, rate of perceived exertion, and SBC showed significant improvement after receiving crocodile breathing as compared to prone positioning (P = 0.001). Crocodile breathing mainly emphasizes diaphragmatic breathing, which improves the efficiency of ventilation, decreases the work of breathing, and increases the excursion of the diaphragm, leading to an increase in chest expansion. It is also seen diaphragmatic excursion led to better gas exchange and oxygenation, which could be one of the factors that SBC showed significant improvement following crocodile breathing.[17] While respiratory rate, pulse rate, and SPO2 showed similar improvements after receiving both crocodile breathing and prone positioning (P > 0.001).

An open-ended, semi-structured subjective question regarding the choice of position between crocodile breathing and prone positioning was asked to the patients after both physiotherapy interventions on Day 1 and Day 2. The answers were recorded and transcripted according to the patient's description of the better position. The majority of patients used words such as “comfortable, better, good, easy, and tolerable” to describe crocodile breathing. Twenty-six participants found crocodile breathing was a more comfortable and better position to relieve dyspnea. The remaining four participants used the “discomfort” word to describe crocodile breathing; therefore, they found prone lying positioning better than crocodile breathing due to difficulty in performing deep breathing. The study has some limitations as it was a pilot study the sample size was less. The rate of perceived exertion, a subjective outcome measure used to assess the perception of breathlessness, differs from patient to patient and hence becomes one of the limitations.

  Conclusion Top

As COVID-19 is still wreaking havoc on the community, the results of this study can be implemented to treat COVID-19 patients along with physiotherapy intervention and medical management. Thus, crocodile breathing can enhance the standard rehabilitation for the COVID-19 study.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Hamid S, Mir MY, Rohela GK. Novel coronavirus disease (COVID-19): A pandemic (epidemiology, pathogenesis and potential therapeutics). New Microbes New Infect 2020;35:100679.  Back to cited text no. 1
Malik YS, Sircar S, Bhat S, Vinodhkumar OR, Tiwari R, Sah R, et al. Emerging Coronavirus Disease (COVID-19), a Pandemic Public Health Emergency with Animal Linkages: Current Status Update. Preprints 2020, 2020030343 (doi: 10.20944/preprints202003.0343.v1).  Back to cited text no. 2
Struyf T, Deeks JJ, Dinnes J, Takwoingi Y, Davenport C, Leeflang MM, et al. Signs and symptoms to determine if a patient presenting in primary care or hospital outpatient settings has COVID-19 disease. Cochrane Database Syst Rev 2020;7:CD013665.  Back to cited text no. 3
Thomas P, Baldwin C, Bissett B, Boden I, Gosselink R, Granger CL, et al. Physiotherapy management for COVID-19 in the acute hospital setting: Clinical practice recommendations. J Physiother 2020;66:73-82.  Back to cited text no. 4
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Guidelines for Chest Physiotherapy Management of COVID-19 in Indian Set-up – MS OTPT Council (2020); June, 2020. Available from: http://www.msotptcouncil.org. [Last accessed on 2020 Aug 10].  Back to cited text no. 6
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Pratt B. Crocodile Breathing: Not Just For Reptiles! Available from: https://fitnesstogether.com/avon/blog/crocodile-breathing-not- just-for-reptiles. [Last accessed on 2020 Oct 14].  Back to cited text no. 8
Cho YH. Effects of crocodile breathing exercise on pain, muscle tone, and muscle stiffness in patients with non-specific low back pain. J Korean Soc Phys Med 2019;14:117-24.  Back to cited text no. 9
Whitehead AL, Julious SA, Cooper CL, Campbell MJ. Estimating the sample size for a pilot randomised trial to minimise the overall trial sample size for the external pilot and main trial for a continuous outcome variable. Stat Methods Med Res 2016;25:1057-73.  Back to cited text no. 10
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Weir CB, Jan A. BMI classification percentile and cut off points. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2020. https://www.ncbi.nlm.nih.gov/books/NBK541070/ [Last updated on 2020 Jul 10].  Back to cited text no. 12
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Bartfield JM, Ushkow BS, Rosen JM, Dylong K. Single breath counting in the assessment of pulmonary function. Ann Emerg Med 1994;24:256-9.  Back to cited text no. 14
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  [Figure 1], [Figure 2], [Figure 3], [Figure 4]

  [Table 1]


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