A round trip voyage between Kagoshima and Solomon Islands via Fiji was made during a 42-day period from November 11 to December 21, 1982 including 6 days stay at Suva, Fiji and 3 days at Honiara, Solomon Islands. During this voyage, the measurements of blood pressure were taken every morning and night for each of four male adult subjects to investigate the relations between blood pressure and atmospheric temperature. The results were as follows: 1) There is no clear trend for blood pressure to increase during the voyage for all four subjects. However, the lowest value was recorded during the stay at Suva for everysubject. 2) A negative correlation between the systolic blood pressure in the morning and outside temperature was present on the return voyage to Kagoshima for subject A aged 43 years but not for two subjects; subject B aged 35 years and subject C aged 33 years. This correlation was present on the way to Solomon Islands for subject D aged 27 years. 3) A positive correlation was present between the diastolic blood pressure in the morning and outside temperature for subject B on the way to Solomon Islands and for subject B and subject C on the return to Kagoshima. For subject D, a negative correlation was present between the diastolic blood pressure in the morning and room temperature. 4) Outside temperature showed no significant correlation with the systolic blood pressure in the late evening for all four subjects during the voyage. For subject C, however, room temperature showed negative correlation with the systolic blood pressure in the late evening. 5) Significant negative correlation between the diastolic blood pressure in the late evening and room temperature were observed for two subjects; subject B and subject C. 6) In conclusion, the patterns of blood pressure variation were different among the different subjects without any consistent relation to outside temperature, suggesting the influence of mental and/or physical load during the voyage as a mediating variable in the link between blood pressure and outside temperature.
