Cold pressor test on the wintering members of the Japanese antarctic research expedition / 日本温泉気候物理医学会雑誌

ABSTRACT

Cold pressor tests were examined on the eight wintering members (mean age 35±SD 4years old) of the 28th Japanese Antarctic Research Expedition to study their autonomic adaptation to local severe cold stress.<br>Tests were carried out 6 times with 3 month intervals through the expedition.<br>The first test was done on the ship in the Indian Ocean, on November 24, 1986 (Test-1). The second (Test-2), third (Test-3), fourth (Test-4) and fifth test (Test-5) were done at the Japanese Antarctic Asuka Base on February 24, 1987, May 20, 1987, August 18, 1987 and November 11, 1987, respectively. The last sixth test (Test-6) was done on the ship in the Antarctic Ocean on February 29, 1988.<br>The left hand was immersed in the ice floated water for three minutes for cold pressor test. Systolic and diastolic blood pressure (SBP, DBP), heart rate (HR) and variation coefficient of R-R intervals (CV_(R-R)) were examined, before immersion (F), at the beginning of immersion (A1), at the end of immersion (A2) and 2 minutes after immersion (A3).<br>An usual sphygmomanometer was used for blood pressure measuring and<br>CARDIMAX FX-102A (FUKUDA) was used for electrocardiogram. HR and CV_(R-R) were calculated from each 50 R-R intervals of ECG. Student's paired t-test was used for statistical evaluation.<br>SBP (A1, A2, A3), DBP (A2) and HR (A1) rose significantly (p<0.05-0.001) in Test-1. The increases in SBP (A3) and DBP (A2) were not observed in Test-2 and those after. The increase in SBP (A1) was observed in Test-2 but not after Test-3. The increase in HR (A1) was observed in Test-2 and Test-4 but not in Test-3 and after Test-5.<br>CV_(RR) (A1, A3) in Test-2 and CV_(RR) (A2, A3) in Test-4 decreased significantly (p<0.05-0.01). CV _(RR) (F) was relatively higher in these tests than others and was within normal range at the Test-3, Test-5 and Test-6.<br>The sympathetic adaptation to local severe cold seems to have advanced in 2 months and completed within 5 months in their Antarctic life. The parasympathetic function might have been excited when the sympathetic adaptation was unstable.