Short-term foot warming impacts foot sensitivity and body sway differently in older adults

Abstract

Background: Aging is accompanied by loss of foot skin sensitivity and reduced postural control. Increasing foot temperature can improve both skin sensitivity and postural control in adults. However, it remains unclear whether similar effects can be observed in older adults.

Research question: Can foot warming improve postural control in older adults, similar to observations in younger adults?

Methods: Two foot warming protocols were conducted in 18 older adults (14 women, 4 men) to increase foot temperature by using infrared radiation to (1) warm the plantar aspect and (2) the skin of the entire foot and ankle area. We assessed the foot skin sensitivity before and after warming, considering tactile stimulation and center of pressure (CoP) displacement during 30-s standing with eyes open and closed.

Results and significance: Both foot warming protocols led to similar increases in skin temperature (∼6 °C) compared to the basal condition, but only warming the entire foot and ankle area increased foot sensitivity for the different regions assessed. No main effects or interactions were found for CoP variables in response to the two warming protocols. The short-term effects identified after warming the entire foot and ankle region suggest that this might be a strategy to improve skin sensitivity in older adults as observed in younger adults, but this was not the case for CoP. Future research should clarify whether the magnitude and long-lasting effects of warming could be determinant of CoP results.

Keywords: Adaptation; Aging; Foot; Neuromechanics; Postural Control.