What question did this study set out to answer?

To evaluate the validity of vaginal temperature compared to rectal temperature during exercise in a hot environment.

May 14, 2026

Validity of Vaginal Temperature During Exercise in the Heat

Key Points

To evaluate the validity of vaginal temperature compared to rectal temperature during exercise in a hot environment.
Involved ten females aged 30±10 years, exercising for 30 minutes in a controlled chamber (27.3°C, 49.7% humidity).
Temperature (rectal and vaginal), discomfort, and heart rate were recorded every 5 minutes during the exercise session.
Data were analyzed using Pearson correlation and repeated measures ANOVA.
Core body temperature increased significantly over time, with a mean difference of 0.19°C (p=0.007) favoring rectal temperature.
Strong correlation found between vaginal and rectal temperatures (r=0.95, p<0.001).
Vaginal temperature exhibited less discomfort compared to rectal temperature, trending towards significance (p=0.089).

Abstract

It used to be dangerous to take vaginal temperature (Tva) due to using glass and mercury thermometers. Today, silicone thermistors offer a safer option for Tva. Over 100 million females in the world use tampons, with 22 to 86% of females in the U.S. using tampons. Females may be more comfortable with Tva versus rectal temperature (Tre) during exercise because this location is more commonly used for external devices during daily activities. PURPOSE: To test the validity of Tva for core body temperature when exercising in the heat. HYPOTHESIS: We hypothesized that Tva would be a valid compared to Tre. METHODS: Ten females (30±10 y, 67.4 ± 20.1 kg, 161.24 ± 4.43 cm) participated in the study. They self-selected a pace on a treadmill or cycle ergometer. They exercised for 30 minutes in an environmental chamber (27.3 ± 0.2°C; 49.7 ± 0.5% relative humidity). Self-reported discomfort (rectal and vaginal), heart rate, and temperature (rectal and vaginal) were measured every 5 minutes during exercise. A Pearson correlation was used to analyze the correlation between Tva and Tre. Repeated measures ANOVA was used to analyze differences between temperatures during trials and between measurements. Alpha level was set a priori < .05. RESULTS: There was a main effect of time difference for temperature to increase during trials (p< .001), regardless of measurement site. There was a main effect difference between measures, regardless of time point (p=.007). The mean difference between temperature measures was for Tre to be greater than Tva (0.19 ± 0.14°C). ΔTva was 1.35 ± 0.36°C, and ΔTre was 1.54 ± 0.41°C (p=.008). Tva and Tre were strongly correlated (.95, p< .001) throughout trials. Discomfort trended towards a difference where Tva was less than Tre (Tva: 0.6 ± 0.1; Tre: 1.2 ± 0.1; p = 0.089). CONCLUSIONS: Internal temperature increased throughout trials using both methods. Tva was significantly less than Tre, regardless of time point. Tva thermistor trended to produce less discomfort than Tre thermistor. Future studies should include more participants and control for the menstrual phase. This abstract was presented at the American Physiology Summit 2026 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.

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Validity of Vaginal Temperature During Exercise in the Heat

Key Points

Abstract

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