Presenter: Madeline Hay
Faculty Mentor: Andrew Lovering, Louise Bishop
Presentation Type: Poster 68
Primary Research Area: Science
Major: Human Physiology
A patent foramen ovale (PFO) is an intracardiac shunt present in ~1/3 of the population that allows blood flow to bypass pulmonary circulation which may reduce respiratory cooling. During passive heating, ventilation increases to dissipate heat from the lungs. Because individuals with a PFO (PFO+) have a higher core temperature (Tcore), it was hypothesized that PFO+ subjects would increase ventilation at a higher Tcore than subjects without a PFO (PFO-) during passive heating and would shiver at a higher Tcore during passive cooling. 22 males (11 PFO+, 11 PFO-) completed a passive heating and passive cooling trial. For passive heating, individuals were immersed in a 40°C water bath until 1) 30 minutes elapsed, 2) Tcore reached 39.5°C, 3) they felt lightheaded or 4) they requested to exit. For passive cooling, individuals were immersed in a 20°C water bath until 1) 60 minutes elapsed, 2) Tcore reached 35.5°C, 3) sustained shivering occurred or 4) they requested to exit. In both trials, PFO+ had a higher Tcore. During passive heating, PFO+ had a lower ventilation than PFO-. Additionally, PFO+ shivered at a higher Tcore than the PFO-subjects during passive cooling. The results suggest that PFO+ have a higher Tcore and that this greater temperature is defended in both hot and cold environments. A PFO may be beneficial by preventing hypothermia but detrimental by facilitating heat stroke.