Core and Skin Temperatures in Men With and Without a Patent Foramen Ovale at Rest and During Exercise

46 pagesIntroduction: During exercise, core (Tc) and skin temperatures (Tsk) increase due to elevations in heat production (Hprod) from increased metabolism by exercising muscles. To maintain Tc and Tsk within a precise range, the body increases skin blood flow to facilitate heat loss primarily from radiation and sweating. Further, there is some additional heat released through breathing. Previous studies have shown that men with a patent foramen ovale (PFO) have a higher Tc at rest and during exercise, possibly due to alterations in thermoregulatory mechanisms (Davis et al, 2015, 2017). Purpose: The purpose of this study was to determine if the presence of a PFO was associated with higher Tc and Tsk at rest and during exercise in healthy adult men while controlling for Hprod. Methods: The study was completed in a thermoneutral environment (20 C, 39% rh). Twenty-one men (11 PFO+ and 10 PFO-), ages 18-35 y/o completed the study. Participants completed 3 study visits. On day 1 they performed non-invasive pulmonary function tests and a cardiac ultrasound to determine the presence or absence of a PFO. On day 2, participants performed a graded exercise protocol at 4 workloads to determine what workload would elicit a Hprod of 7 W/kg of body weight, followed by a VO_2 peak test. On visit 3, participants completed a 1 hour cycling protocol at the previously determined workload that would elicit a Hprod of 7W/kg, which was confirmed using metabolic data during the 1-hour bout. Tc, measured by a telemetric pill, and Tsk, measured with skin thermistors on 4 sites of the body, were measured continuously. Results: Participants without a PFO (PFO-) had significantly higher (p