Thermoregulatory effects of guava leaf extract-menthol toner application for post-exercise use

Abstract

Context

Psidium guajava L. (Myrtaceae) leaf contains a wide variety of bioactive compounds that contribute valuable effects on human well-being.

Objective

This study investigates the influence of guava leaf extract-menthol toner on thermoregulation, including perspiration, skin temperature, and recovery heart rate.

Materials and methods

This randomised, placebo-controlled clinical trial assessed the effects of the guava leaf extract-menthol toner and placebo with a 1-week washout period. Sixty-four participants were enrolled. The participants exercised on a treadmill until a 75% heart rate reserve was achieved for 5 min, followed by a 5 min post-exercise rest period. The skin temperature and heart rate were then measured before 5 mL of the testing product was sprayed to specific areas of the body, left it for 30 sec before wiped off. Post-exercise perspiration and skin temperatures were collected by sweat patches and measured by the Skin-thermometer ST500, respectively. A 20 min heart rate monitoring period started 10 min after the exercise and measured every 2 min intervals.

Results

Use of the toner significantly reduced post-exercise perspiration to approximately half of the baseline and placebo use values (p < 0.05). Furthermore, relative heart rate changes showed no significant differences among the tests (p > 0.05). Skin temperature was also unaffected (p > 0.05).

Discussion and Conclusion

Guava leaf extract-menthol toner reduced perspiration by astringent effects but did not influence heat dissipation and did not affect cardiovascular mechanism compared to the controls. Additional cleaning with guava leaf extract-menthol toner could offer better hygiene after a workout.

Keywords:

• Astringent
• sweating
• skin temperature
• heat dissipation
• personal hygiene

Acknowledgments

The authors would like to thank all the participants, Faculty of Pharmaceutical Sciences, Faculty of Allied Health Sciences, and Faculty of Sports Science, Chulalongkorn University for facilitating and supporting the completion of this study.

Disclosure statement

The authors report no conflict of interest.

Additional information

Funding

This research was funded by the 100^th Anniversary Chulalongkorn University Fund for Doctoral Scholarship and the 90^th Anniversary Chulalongkorn University Fund (Ratchadaphiseksomphot Endowment Fund).