An exploratory assessment of regional cutaneous vasodilator responses to local heating in young and older females

Objective

To explore regional differences and potential age effects in cutaneous vascular conductance (%CVC_max) during local heating in young and older females.

Methods

In 10 young (21.4 ± 3.4 years) and 10 older (69.8 ± 2.7 years) females, %CVC_max was assessed using laser-Doppler flowmetry at the chest, abdomen, forearm, and thigh during rapid, local skin heating. Local temperature was set at 34 °C during baseline and increased to 39 °C, then 42 °C in 30 min increments each. Differences in %CVC_max between and within age groups were evaluated at baseline, the initial vasodilator peak, and both the 39 °C and 42 °C heating plateaus.

Results

In young females, responses were similar across regions with the exception that %CVC_max was reduced for the abdomen across heating phases relative to other regions (all P < 0.040). In contrast, calf responses in older females were greater compared to other regions during the 39 °C plateau only (all P < 0.049). %CVC_max was greater at the abdomen during the 42 °C plateau (P = 0.022) for older females compared to young. Similarly, responses pooled across sites were significantly different (P = 0.035).

Conclusion

In our exploratory study we observed regional differences for both young and older females, and the pattern of response and the heating phases where differences occurred varied. Further, no age-related differences in %CVC_max were observed apart from a marginally greater response for older females at peak heating of 42 °C. These findings highlight the need to disentangle the effects of sex and age in evaluating the vascular responses to heat and provide a critical foundation for sex-specific investigations into microvascular dysfunction.