Holding breath may increase risk of getting COVID-19: IIT Madras research

Researchers at the Indian Institute of Technology (IIT) Madras have found that holding breath may increase the risk of getting COVID-19 infection.

The researchers modelled breathing frequency in a laboratory to better understand how the rate of flow of droplet laden with virus determines its deposition in the lungs. The findings of the study have also been published in the international reputed peer-reviewed journal Physics of Fluids.

According to the team, they modelled the breathing frequency in a laboratory and found that low breathing frequency rises the time of residence of the virus and therefore it increases chances of deposition and consequently the infection. Also, the multiscale lung structure has a significant effect on a person's susceptibility to COVID-19.

"COVID-19 has opened a gap in our understanding of deep pulmonological systemic diseases. Our study unravels the mystery behind how particles are transported and deposited in the deep lung.

"The study demonstrates the physical process by which aerosol particles are transported into the deep generations of the lung," said Mahesh Panchagnula, Professor at Department of Applied Mechanics, IIT Madras.

He said that they have found that holding breath and having low breathing rate can increase chances of the virus deposition in the lungs.

The study was conducted to pave the way for developing better therapies and drugs for respiratory infections. The other members of the team included research scholars Arnab Kumar Mallik and Soumalya Mukherjee, IIT Madras.

"Airborne infections such as coronavirus spread immensely through sneezing and coughing as it instantly releases a lot of tiny droplets. The team 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. 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. 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," Panchagnula said.

The researchers also studied how the 'Reynolds Number' a parameter that quantifies the nature of flow - steady or turbulent - and 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.

"In the future, the team intends to continue this 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," he said.

Panchagnula said an understanding of the physics of this phenomenon could be crucial in mitigating the progression of the disease.