We studied the effects of transcutaneous electrical nerve stimulation (TENS) of Baxie on local cold tolerance as an index of cold induced vasodilatation (CIVD). The subjects consisted of 22 healthy adult volunteers.
The skin temperature and skin blood flow in the middle finger were measured simultaneously before, during, and after immersing the finger in cold water. TENS at 1Hz with 100-V intensity was applied for 5 minutes before immersion of the finger.
Experiments were conducted with no stimulation and with TENS on the same subjects on different days.
The results revealed the following:
1. The minimum skin temperature and minimum skin blood flow during immersion of the finger in cold water were higher in the TENS group than in the control (no stimulation) group.
2. The maximum skin temperature, mean skin temperature, and increase and decrease of skin blood flow rate during immersion of the finger in cold water and in the rising phase of skin temperature were higher in the TENS group than in the control group.
3. The index of resistance to frostbite was higher in the TENS group than in the control group.
4. The number of fluctuations in skin temperature during immersion of the finger in cold water was significantly higher in the TENS group than in the control group.
5. The incidence of abnormal perception during immersion of the finger in cold water was lower in the TENS group than in the control group.
These results suggest that TENS enhances the local cold tolerance of fingers by suppressing SSA in the initial falling phase on skin temperature and increasing the motion of skin blood vessels in the rising phase of skin temperature.