BACKGROUND: Altered localized microclimate conditions are known to increase the risk of pressure injuries in immobile patients. Limited in vivo studies have examined how skin properties change over time and under different skin microclimate conditions. OBJECTIVE: To examine changes in erythema, stratum corneum hydration, and skin temperature in response to an altered microclimate, simulated by the introduction of heat, at the skin-support surface interface of semirecumbent healthy adults. METHODS: In this quasi-experimental study, researchers obtained noninvasive biophysical skin measures at the elbows, heels, and sacrum of healthy adults positioned semirecumbently. Participants advanced through a controlled condition and heat intervention. Repeated measures were gathered at the anatomic sites every 10 minutes for 60 minutes per condition. Linear mixed models were used to compare skin measures over time and between conditions. RESULTS: Large regional variation in skin measures emerged by condition and among participants. The introduction of heat increased skin temperature at the heels (P <
.001), elbows (P = .005), and sacrum (P <
.001). Erythema increased at the sacrum (P = .012) but at no other anatomic testing site. There was no impact on stratum corneum hydration as a result of increased heat at any anatomic testing site. CONCLUSIONS: More frequent monitoring cycles for erythematous skin discoloration and thermal changes may be required at the sacral skin in immobile patients. Distinctive protocols in relation to skin-care regimens may be warranted for individual patients. Skin cooling, enabled by intermittent off-loading of pressure-prone areas, may assist optimization of the skin microclimate.