Introduction: In the current scenario of the COVID 19 pandemic, the protective reflexes,
namely sneeze and cough, have received great importance. However, it is not in terms of protection
but in terms of the spread of infection. The present review tries to bring out the correlation between
the physiology of sneeze and cough, taking into consideration the various receptors that initiate
the two reflexes, then correlating it with the formation of expelled droplets and the significance
of various aspects of droplets that lead to the spread of infection.
Material and Methods: For the compilation of the present review, we searched the terms “Physiology
of cough”, “Physiology of sneeze”, “droplets”, “aerosols” and “Aerosols in COVID 19”. The
above-mentioned terms were extensively searched on PubMed, Google Scholar, and google search
engine. After reviewing the various available material, the most significant research has been considered
for this review.
Conclusion: Through this review, we conclude that there are various factors responsible for the initiation
of sneeze and cough, but in the case of infection, it is mainly the inflammatory reaction that
directly stimulates the receptors to produce the reflex outburst air. As the flow of air during expiration
is turbulent, it causes damage to the Epithelial Lining Fluid present in the respiratory conduit.
In addition, it gets admixed with the saliva in the oropharynx and oral cavity and mucus in the nose
to form droplets of various sizes. Large droplets settle close and are responsible for droplet and
fomite transmission, but the smaller droplets remain suspended in the air and travel farther distances
to cause airborne transmission. The spread of droplet cloud in sneezing may range to 6m or
more as compared to cough; hence the concept of 1m to 2m of social distancing does not hold reliable
if the patient is sneezing.