Influence of Regional Climate on Basal Metabolism

Abstract

In a country long and narrow compared with its area such as Japan, there is a tolerable provincial difference in external temperature between the Northern region and the Southern region. It must therefore be natural to consider that external temperature difference has effects on the basal metabolism (BM) of the population.Though we have already reported that the seasonal BM has a close relation with external temperature, there still remains room to doubt whether a completely identical relation such as this can exist in regional climate difference, because in cold and warm regions clothing and heating, i. e., artificial climate conditions differ; besides this, the individual difference of exposure time to such artificial temperature must also be considered.Taking winter for example, heating conditions are satisfactory in the Northern region and people spend more time of their every-day life indoors. While in the Southern region though the external temperature is not exceedingly low, room temperature is almost equivalent to external temperature as heating conditions are unsatisfactory and people are under the influence of external temperature all day long.From this point of view, we have carried out BM observations on personnel of the Self Defence Forces since 1950, a total of 1453 persons in number, selected through out the country mainly in summer and winter. These men were selected as subjects for the reason that they are scattered all over the country and also because their labor and other living conditions are identical.Results of BM measurements are presented in the next table and figures: Table shows each value; Figure 1 localizations of subjects; Table 2 relation of external temperature and BM of entire subjects; Table 3 relation of external temperature and BM of infantry corps only, dots in the figures indicate average BM values of each region.From these data the following tendency is evident:1. BM values are in reverse proportion to external temperature.2. BM has a tendency to increase abruptly with temperature-decrease till 10°C attained. At temperatures above an increase of approximately 5% for each 10° is observed with temperature-decrease.At temperatures lower than 10°C this inclination declines. There is a 1-2% BM increase with a 10° decrease in temperature.This trend mentioned above is completely reverse to naked-cold exposure in an air conditioned room. This may he attributed to protection from cold by means of heating and clothing and spending more time of their everyday life indoors in Northern region.Observing the entire temperature range there is an apprx. 2.5% increase in BM values for every 10°C decrease in temperature, this coefficient being almost in consistence with seasonal variation.