Pokora Ilona, Wyderka Piotr, Pilis Wiesław, Pilis Karol
Institute of Sport Sciences, Jerzy Kukuczka Academy of Physical Education, 40-065 Katowice, Poland.
Collegium Medicum, Jan Dlugosz University, 42-200 Czestochowa, Poland.
J Clin Med. 2025 Aug 13;14(16):5735. doi: 10.3390/jcm14165735.
Maintaining thermal homeostasis is a basic function of the human body. This homeostasis depends largely on the body's nutritional status and other conditions related to it. The present study investigated the impact of 8 days of water-only fasting (8DW-F) on selected features of thermal homeostasis, taking into account somatic, metabolic, and circulatory changes in middle-aged men. A total of 13 healthy men took part in the experiment. Volunteers were examined twice: after a mixed diet (C) and after using 8DW-F. At baseline, the following were recorded: body mass (BM), body fat (FM), fat-free mass (FFM), and total water (TBW), along with basal metabolic rate (BMR) and body surface area (BSA). Then, after 30 min of sitting under thermoneutral conditions, the following measurements were taken: eardrum temperature (Ti), skin temperatures (Tsk), heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), oxygen uptake (VO), and respiratory exchange ratio (RER). The following were then calculated: average body (MTB) and skin temperature (MTsk), resting metabolic rate (RMR), body to skin temperature gradient (g), and whole-body thermal conductivity (C). The results showed that 8DW-F cause a significant reduction in most somatic variables as well as SBP and BMR ( < 0.001), RMR ( < 0.05) with no changes in Ti, MTsk, MTB, or C and g = 0.09). There were also significant correlations between Δ MTB × Δ BMR ( < 0.05) and Δ RMR × Δ VO ( < 0.001). Moreover, changes in the C range correlated with Δ RMR ( < 0.005) and Δ DBP ( < 0.05). 8DW-F reduced resting metabolic heat production in the studied men, but sufficient heat conservation ensured that thermal homeostasis was maintained under thermally neutral conditions.
维持热稳态是人体的一项基本功能。这种稳态很大程度上取决于身体的营养状况以及与之相关的其他条件。本研究调查了为期8天的纯水禁食（8DW - F）对热稳态选定特征的影响，同时考虑了中年男性的身体、代谢和循环变化。共有13名健康男性参与了该实验。志愿者接受了两次检查：一次是在混合饮食后（C），另一次是在采用8DW - F之后。在基线时，记录了以下各项：体重（BM）、体脂（FM）、去脂体重（FFM）和总水量（TBW），以及基础代谢率（BMR）和体表面积（BSA）。然后，在热中性条件下静坐30分钟后，进行了以下测量：鼓膜温度（Ti）、皮肤温度（Tsk）、心率（HR）、收缩压（SBP）、舒张压（DBP）、摄氧量（VO）和呼吸交换率（RER）。随后计算了以下各项：平均体温（MTB）和皮肤温度（MTsk）、静息代谢率（RMR）、体核与皮肤温度梯度（g）以及全身热导率（C）。结果表明，8DW - F导致大多数身体变量以及SBP和BMR显著降低（<0.001），RMR降低（<0.05），而Ti、MTsk、MTB或C以及g均无变化（g = 0.09）。ΔMTB×ΔBMR之间（<0.05）以及ΔRMR×ΔVO之间（<0.001）也存在显著相关性。此外，C范围的变化与ΔRMR（<0.005）和ΔDBP（<0.05）相关。8DW - F降低了所研究男性的静息代谢产热，但足够的热量保存确保了在热中性条件下热稳态得以维持。
