Previous recreational cold exposure does not alter endothelial function or sensory thermal thresholds in the hands or feet

This study investigated whether cold sensitive (CS) individuals, who rewarm more slowly following a mild cold challenge, have impaired endothelial function and sensory thermal thresholds (STT) and whether this was related to reported cold exposure. Twenty seven participants with varying previous cold exposure undertook three tests: STT: warm and cold STT of the fingers and dorsal foot. Endothelial function: measurement of cutaneous vascular conductance (CVC) during iontophoresis of acetylcholine on the forearm, finger and foot. CS test: involving immersion of a foot for 2 minutes in 15°C water followed by 10 minutes of rewarming in 30°C air. Toe skin temperature (Tsk) measured during the CS test was used to form a CS group (< 32°C prior to and 5 minutes after immersion) and an otherwise closely matched CONTROL group (Tsk > 32°C; n = 9 [4 women] for both groups). A moderate relationship was found between cold exposure ranking and Tsk rewarming (r = 0.408, P = 0.035, n = 27) but not STT or endothelial function. Tsk and blood flow were lower in CS compared to CONTROL before and after foot immersion (Tsk, mean [sd]: 30.3 [0.9]°C v 34.8 [0.8]°C; 27.9 [0.8]°C v 34.3 [0.8]°C; P < 0.001. CVC: 1.08 [0.79] flux.mmHg⁻¹ v 3.82 [1.21] flux.mmHg⁻¹; 0.79 [0.52] flux.mmHg⁻¹ v 3.45 [1.07] flux.mmHg⁻¹, n = 9, P < 0.001 respectively). However, no physiologically significant differences were observed between groups for endothelial function or STT. A moderate correlation between previous cold exposure and toe Tsk rewarming following foot immersion was observed however, CS was not associated with impaired endothelial function or reduced thermal detection.