Koroška 8000 Himalayan expedition: digit responses to cold stress following ascent to Broadpeak (Pakistan, 8051 m)

Jurij Gorjanc, Shawnda A. Morrison, Adam C. McDonnell, Igor B. Mekjavic

Cold-induced vasodilatation (CIVD) is a peripheral blood flow response, observed in both the hands and feet. Exercise has been shown to enhance the response, specifically by increasing mean skin temperatures (Tsk), in part due to the increased number of CIVD waves. In contrast, hypobaric hypoxia has been suggested to impair digit skin temperature responses, particularly during subsequent hand rewarming following the cold stimulus. This study examined the combined effect of exercise and hypobaric hypoxia on the CIVD response. We compared the CIVD responses in the digits of both the hands and feet of a team of alpinists (N = 5) before and after a 35-day Himalayan expedition to Broadpeak, Pakistan (8051 m). Five elite alpinists participated in hand and foot cold water immersion tests 20 days before and immediately upon return from their expedition. The alpinists summited successfully without supplemental oxygen. Post-expedition, all alpinists demonstrated higher minimum Tsk in their hands (pre: 9.9 ± 1.1, post: 10.1 ± 0.7 °C, p = 0.031). Four alpinists had either greater CIVD waves, and, consequently, higher mean Tsk in their hands, or higher recovery temperatures (pre: 26.0 ± 5.5 °C post: 31.0 ± 4.1 °C, p = 0.052), or faster rewarming rate (pre: 2.6 ± 0.5 °C min-1 post: 3.1 ± 0.4 °C min-1,p = 0.052). In the feet, the responses varied: 1/5 had higher wave amplitudes and 1/5 had higher passive recovery temperatures, whereas 3/5 had lower mean toe temperatures during cold exposure. The results of the cold stress test suggest after a 35-day Himalayan expedition, alpinists experienced a slight cold adaptation of the hands, but not the feet.