Doctoral Dissertation Research: Nasal morphological responses to variably thermal and exertional conditions

Because the human nose’s function is to heat and humidify inhaled air during respiration, variation in nasal morphology is hypothesized to result from evolutionary selective pressures that different groups experienced in the climates where they lived. However, that assertion is based on skeletal studies that cannot assess the function of a fully fleshed nose.

This doctoral dissertation project bridges this knowledge gap by evaluating the contributions of soft and bony tissues to nasal morphology and function in a large sample of living humans under experimentally controlled climatic conditions. The study advances scientific understanding of human climatic adaptation. The anatomical and physiological data generated by this study are made freely available to other anthropologists and the broader scientific community, enhancing the capacity for future interdisciplinary research focusing on climate change and respiratory health.

This research supports the training of the next generation of scientists through research experiences for undergraduate and medical students, along with unique STEM education opportunities for Texas high school students from disadvantaged backgrounds.

It has been hypothesized that inhalation of cold air and physical exercise cause the nasal mucosa to rapidly decongest. Yet, the degree to which thermal and exertional stimuli actually influence mucosal congestion, and thus nasal airflow dynamics, remains poorly understood. This study employs a non-invasive technique, acoustic rhinometry, to quantify changes in the nasal soft tissue morphology of living human participants during experimental exposures to different thermal conditions and exercise regimes within a climate-controlled environmental chamber.

These data are then used to generate 3D digital reconstructions of participant nasal passages during each experimental condition, and subsequently, to quantify respiratory airflow variables (e.g., airstream directionality, velocity, heat/moisture transfer) using Computational Fluid Dynamics analysis. Resultant measures of nasal soft-tissue morphology and airflow parameters are then assessed in conjunction with CT-derived measures of skeletal anatomy to: (1) explicitly test whether the nasal skeleton reliably predicts soft-tissue nasal morphology, (2) empirically assess proposed functional (i.e., adaptive) benefits of various nasal morphologies in different climates, and (3) potentially identify new skeletal indicators of climatic adaptation.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.