Exposure to a Warm Virtual Reality Increases Heart Rate Responses During Prolonged Exercise Despite Lower Core Body Temperature

Cardiovascular (CV) drift, a gradual increase in heart rate during prolonged exercise as a result of hyperthermia, remains a complex physiological phenomenon. There are two accepted theories that may explain the CV drift – the shunting of blood for thermoregulatory processes, or the direct impact of hyperthermia on heart rate – but whether simply viewing a hot environment can induce the CV drift has not been studied. The purpose of the study was to test the hypothesis that the magnitude of CV drift changes when participants are shown either a hot (HOT) or cold (COLD) virtual reality during exercise, despite the physical environment and exercise bout being identical between the groups. Five women (n=5) have completed the study, (age: 21.4 ± 2.1 years, height: 163.4 ± 4.0 cm, mass: 63.8 ± 6.3 kg). Participants engaged in repeated exercise bouts at a fixed work rate (5W/kg of metabolic heat production) for 40 minutes. Heart rate (HR), blood pressure (BP), and core body temperature (T core ) were recorded every 5 minutes throughout the trials. Our analysis of cardiovascular measures under the two visual conditions (COLD vs HOT) did not demonstrate any significant differences (main effects & interactions, p>0.05). However, the % change in HR at the end of the 40-minute exercise bout was trending higher in the HOT condition, relative to COLD (HOT: 9.8 ± 3.7% vs COLD: 5.4 ± 3.9%, p=0.13). This increase in HR is apparent despite T core being significantly lower at the same time point in the HOT condition (HOT: 0.77 ± 0.19 vs COLD: 0.97 ± 0.25°C, p=0.04). Upon comparing the change in HR (ΔHR) for a given change in T core , the slopes of the relationship between ΔT core and ΔHR were significantly higher in the HOT (21.32 ± 1.96 bpm/°C) compared to COLD (10.24 ± 1.04 bpm/°C) conditions (p=0.0007). These preliminary data suggest that the CV drift could occur, despite a lower T core , by viewing a hyperthermic environment. This indicates that the visual and psychological factors we encounter during exercise may make a notable contribution to the magnitude of the cardiovascular drift seen during exercise. Further research is needed to understand the thermoregulatory neural pathways that stem from the visual centers, along with how the visual environment influences physiological responses at rest and during exercise. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.