Thermal resting pattern and acute skin temperature response to exercise in older adults: Role of cardiorespiratory fitness

Background: Infrared thermography is a growing area of interest in sports science due to the potential of skin temperature (T-sk) measurements to provide valuable information from rest to exercise. However, limited research exists on T-sk in older adults and the impact of factors such as sex and cardiorespiratory fitness (CRF) on T-sk. This study aims to investigate T-sk at rest and after acute exercise in older adults and assess whether sex or CRF influences T-sk. Methods: Ninety-two participants (41 women, 68.48 +/- 3.01 years) were examined with a thermographic camera in a conditioned room (23.02 +/- 3.01 degrees C) at rest and after a graded protocol. The T-sk of 25 regions of interest (ROIs) were extracted and analysed. Results: Men had higher overall T-sk at rest in 76% of ROIs, showing significant differences (p < 0.010) in six specific ROIs, independent of CRF. Both sexes had similar T-sk responses after graded exercise, with increases in distal parts (1.06 +/- 0.50 C-degrees), decreases in proximal parts (-0.62 +/- 0.42 degrees C), and stable central T-sk (0.23 +/- 0.59 degrees C). Increases in lower limb T-sk were significantly associated with CRF in men and women (beta = 0.438, p = 0.001, and beta = 0.535, p < 0.001, respectively), explaining 17% and 27% of the variance, respectively. Conclusions: This study demonstrates a sex-specific effect on resting T-sk in older adults, suggesting that sex-specific T-sk patterns should be considered when analysing T-sk in this population. Additionally, the association between increases in lower limb T-sk and CRF suggests that T-sk could be a promising predictor of CRF in older adults.

Automated summary

This study investigates the skin temperature in older adults at rest and after acute exercise, and assesses the influence of sex and cardiorespiratory fitness (CRF) on skin temperature. The study finds that sex has a specific effect on resting skin temperature in older adults, and there is a significant association between increases in lower limb skin temperature and CRF.