Cryotherapy: Don't freeze out the cardiovascular consequences of cold pain
Dr. Thad E. Wilson Ph.D
Medicine and Health Sciences
INTRODUCTION: Cold limb immersion, a form of cryotherapy, can cause cardiovascu-lar changes due to cold-pain induced autonomic reflex. OBJECTIVE: This cryotherapy treatment side-effect has received less attention, and could have direct implications for the physical rehabilitation of individuals who have cardiovascular co-morbidities. METHODS: To test hypotheses related to the pressor effects of limb and surface area of cryotherapy, two common lower limb injury sites (the ankle and knee) were immersed into cold water for 15 min at 1-3°C and then referenced to a standard cold pressor test (CPT). Beat-by-beat arterial blood pressure (finger photoplethysmogra-phy), heart rate (ECG), systemic vascular conductance (SVC; Modelflow), and calf VC (venous occlusion plethysmography) were measured in 14 healthy participants. RESULTS: At 2 min, CPT increased mean arterial pressure (MAP; 21±4 mmHg) to a greater degree than either ankle or leg immersion (15±4 and 15±5 mmHg, respective-ly; P=0.015). SVC and calf VC decreased but were not different across treatments (P=0.713). MAP and SVC were not different from 2 min to 15 min of immersion (P=0.164 and P=0.522), but calf VC decreased further by the end of immersion (3.1±0.5 to 2.8±0.4 and 2.7±3 to 1.7±0.2 units; P=0.028). MAP increases to CPT were similar on CPT day and when CPT followed ankle or leg immersion (27±5 and 23±4 mmHg, respectively; P=0.199). CONCLUSION: These data indicate ankle and leg immersion cause a significant but equivalent increase in arterial blood pressure, but immersion of the hand causes a greater pressor response. Thus, the location but not the precise surface area of immersion of cryotherapy appears to be an important factor. No cold-pain habituation or progressive change of MAP was observed from the initial immersion, but significant decreases in non-immersed calf VC were observed during the duration of cryotherapy. Rehabilitative specialists should consider the effect of these responses when recommending cryotherapy to patients with cardiovascular conditions.
Copyright 2019 all authors
McDowell, Jasmine M. OMS-2; Krause, B. Andrew Ph.D, ATC; Addington, Gretchen MS; and Wilson, Thad E. Ph.D, "Cryotherapy: Don't freeze out the cardiovascular consequences of cold pain" (2019). MU-COM Research Day. 151.