Holding breath may increase risk of Covid-19 infection: IIT-M researchers

Holding the breath and having low breathing rate could increase the risk of contracting the novel Coronavirus, researchers at the prestigious Indian Institute of Technology-Madras (IIT-M) have found. The researchers have also found that the process of virus-laden droplets being transported into deep lung increases with decreasing breathing frequency.

The findings of the research led by Prof. Mahesh Panchagnula, Department of Applied Mechanics, IIT-M with his research scholars Arnab Kumar Mallik and Mr Soumalya Mukherjee, of the institute have been published in Physics of Fluids, an international reputed peer-reviewed journal.

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The research team modelled the breathing frequency in a laboratory and found that low breathing increases the time of residence of the virus. The researchers concluded that the above mentioned factor increases the chances of deposition and consequently the infection.

Also, the multi-scale lung structure has a significant effect on a person’s susceptibility to COVID-19, the researchers said, adding that their study unravels the mystery behind how particles are transported and deposited in the deep lung.

“COVID-19 (the disease caused by novel coronavirus) has opened a gap in our understanding of deep pulmonological systemic diseases...The study demonstrates the physical process by which aerosol particles are transported into the deep generations of the lung,” Prof. Panchagnula said.

Airborne infections such as Coronavirus spread immensely through sneezing and coughing as it instantly releases a lot of tiny droplets. The researchers imitated the droplet dynamics in the lung by studying the movement of droplets in the small capillaries which were of a diameter similar to bronchioles.

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“They took water mixed with fluorescent particles and generated aerosols from this liquid using a nebulizer. These fluorescent aerosols were used to track the movement and deposition of particles in the capillaries,” the IIT-M said in a statement on Monday.

The study, which was conducted to pave the way for developing better therapies for respiratory infections like Coronavirus, concluded that holding the breath and having low breathing rate can increase chances of virus deposition in the lungs.

The researchers studied the movement of the fluorescent aerosol particles in capillaries of size ranging from 0.3 to 2 millimetres which covers the range of bronchiole diameters. “They found that the deposition is inversely proportional to the aspect ratio of capillaries, which suggests that the droplets are likely to deposit in longer bronchioles,” the statement added.

The scientists also studied how the ‘Reynolds Number,’ a parameter that quantifies the nature of flow – steady or turbulent – determines the deposition in the capillaries. They found that when the flow of aerosol movement is steady then the particles deposit via the process of diffusion, however, if the flow is turbulent then the particles deposit via the process of impaction.

The research team intends to continue its work to understand how the virus-laden droplets are transported into lungs as the process by which the virus is transported from the nasal cavity to the deep lung is still unknown. “An understanding of the physics of this phenomenon could be crucial in mitigating the progression of the disease,” the IIT-M researchers said.