Correlations between basal metabolic rate in humans with different age, gender, BMI and local earth magnetic field activity

1. Introduction

The human body constantly requires energy to exist. Daily energy expenditure includes resting metabolism (RMR), endogenous thermogenesis (or thermal effects of food), and energy expenditure associated with exercise [1], [2]. Most physically inactive people RMR accounts for 60 % and 70 % of their total daily energy needs, while in physically active people it only accounts for about 50 % [1]. The determination of RMR should be performed on an empty stomach, at rest, and after a period of physical and psychological relaxation [1], [2].

RMR depends on body weight, age, gender, genetic factors, and medications used [1], [2] as well as health status [3].

Energy consumption is determined by cellular mass [2], so individuals with a higher body mass index have a higher RMR than individuals with a lower BMI [4]. Studies have shown that weight loss results when there is a decrease in RMR [4]. Baseline metabolic rate (BMR), as well as RMR, is thought to decrease markedly with age. Changes in organ weight with age have a significant effect on BMR [5], and it has been hypothesized that age-related loss of muscle mass may affect energy expenditure associated with both central regulatory processes and peripheral cellular mechanisms [6].

Studies have shown that RMR changes over a lifetime. The first rapid decline in RMR occurs from birth to age 30, and the second at a much slower rate from adulthood to death. At the age of 25-30, when the human body reaches its maximum level of complexity and maturity, its RMR is 70 % of its value [7]. Throughout life, women typically have a lower RMR than men. It is likely that body composition and different hormonal patterns at least partly account for such differences [7].

Studies show that people aged 40-96 who do not have a major health problem have a significantly lower RMR than those who are ill and / or functionally disabled [3]. In some diseases - COPD, diabetes, heart failure, oncological diseases - an increase in RMR is observed in their initial stage [5], [8], [9]. Additional energy is needed to neutralize chronic diseases and maintain biological homeostasis, as the body works harder to sustain biological processes and life [3], [9]. This energy demand is met by increasing the RMR at the expense of physical and cognitive energy [7]. When the metabolic reserve and body mass becomes depleted, a decrease in RMR is observed [8], physical and cognitive weakness develops, and eventually disability [7]. Thus, a high RMR can be a biological marker that provides information on the degree of instability in energy metabolism, the current use of energy reserves, and the risk of deterioration in health [3], [7].

Every living organism is affected by external factors. Fluctuations in magnetic fields can affect almost every biological system more or less, depending on the characteristics of the particular biological system and magnetic fluctuations [10]. There is a growing body of research showing that solar and geomagnetic activity affect a variety of human health and behavioral processes, with the cardiovascular and nervous systems being the most sensitive [11]. The response of the autonomic nervous system (ANS) to changes in solar and geomagnetic activity was investigated in numerous studies [11], [12]. An increase in solar wind intensity was observed to be associated with an increase in heart rate, which the researchers interpreted as a stress-specific response while increases in cosmic rays, solar radio flux, and Schumann resonance power was associated with increased HRV and parasympathetic activity [12], [13]. In another study after analyzing the data of the local magnetic field change registered by the magnetometer operating in Lithuania, the possible correlations between the time-varying intensity of the local Earth's magnetic field and the frequency of myocardial infarction were investigated [14]. The results showed that the Earth's magnetic field is related to the number of acute myocardial infarction with ST-segment elevation (STEMI) events per week and the average weekly geomagnetic field strength at different frequency ranges. Correlations varied in different age groups, as well as in men and women, which may indicate different sensitivities of the organism to the Earth’s magnetic field [14]. Reviewing the literature on the health effects of geomagnetic interference, Palmer et al. suggests the following conclusions: 1) geomagnetic disturbances have a greater impact on people in higher (northern) geomagnetic latitudes; 2) abnormally high geomagnetic activity affects the health of the cardiovascular system; 3) abnormally low geomagnetic activity has a negative effect on health; 4) Disrupted geomagnetic activity has a negative impact on the health of about 10-15 % of people living in the study areas. 5) HRV is negatively correlated with geomagnetic interference [15], [11]. Thus, research findings support the hypothesis that environmental magnetic activity affects psychophysical processes that can affect people in a variety of ways, depending on their sensitivity, health status, and ability to self-regulate [12].

The aim of this study: to investigate the correlations between basal metabolic rate in humans with different age, gender, BMI and local Earth magnetic field activity.

2. Methods

3. Results

In article [17] we reported on the analysis of 5 years of basal metabolic rate features and LGMF changes. In this article we report on the analysis of correlations between LGMF and basal metabolic features: M_RMR, VO₂, VCO₂ in relation to different ages, gender and BMI (body mass index – human mass divided on the height in square [kg/cm²]). All participants were divided into two groups according gender. Than women and men groups were divided into two groups according to mean age, (mean was 46 years). We analysed correlations in younger women (≤ 46 years) and older (> 46 years) groups and the same for younger men (≤ 46 years) and older (> 46 years). We then looked at all women and all men, then the younger women group, older women group, younger men group and older men group which was divided according BMI mean (29), with less than ≤ 29 BMI and with more than > 29 BMI.

Fig. 1Correlations between LGMF and different age in women and men

a) Women

b) Men

In Fig. 1(a) and in 1(b) it is interesting to note, that with age negative correlations with LGMF in the womens group increase. In the mens group, we see decreasing of the same correlations, along with small changes with age in O₂ consumption, but large changes in CO₂ production and M_RMR. In the women group the changes in the negative correlations with LGMF with age are quite opposite – in the correlation of LGMF and O₂ consumption, CO₂ production and the increased R_BMR. More detailed correlation presentation can be found in Table 1 for women and for men. We can conclude that correlations are stronger for younger men and older women. Men have higher correlations with O₂ consumption, and women with CO₂ production.

Analysis of correlations between LGMF and BMI in women and men groups show more simple changes – basal metabolic features have smaller negative correlations in persons with bigger BMI and women and men, (Fig. 2(a) and 2(b)).

Here again we can see differences between women and men in the correlations between LGMF and O₂ consumption and CO₂ production (Table 2). Such behaviour of those correlations in different genders is difficult to interpretate.

Fig. 2Correlations between LGMF and metabolic features in women and men with BMI less than or 29 and with BMI > 29

a) Men

b) Women

In younger persons (Fig. 3(a) and 3(b)), we have decrease in the correlations between LGMF and basal metabolic features, except in the younger womens group in O₂ consumption – where the negative correlation increases, although not significantly.

Fig. 3Correlations between LGMF and metabolic features in younger than 46 years women and men with BMI less than or 29 and with BMI > 29

a) Women

b) Men

Tables 3 show the correlations for younger persons with different BMI. The biggest correlations we found was in younger men with a BMI of less then 29.

In Fig. 4(a) and 4(b), for older persons we can see the same tendency as in young persons, the correlations between LGMF and basal metabolic rate features were slightly decreased. But again, one interesting feature – in older mens group, the O₂ consumption and CO₂ production was about the same as in men with a BMI ≤ 29 and in men with a BMI > 29, where the M_RMR became even slightly positive. Regrettably those changes where not significant due to the small number of participants.

Fig. 4Correlations between LGMF and metabolic features in older than 46 years women and men with BMI less than or 29 and with BMI > 29

a) Women

b) Men

Tables 4 shown the correlations for older persons with different BMI. The biggest correlations we found was in older women with a BMI less than ≤ 29.

4. Discussion

The results were interesting in the fact, that with few exceptions, correlations between LGMF and basal metabolic features parameters were negative, many of them significant. This means, that when LGMF activity increases, basal metabolic features parameters decrease. This suggests that when the LGMF activity, which the time varying aspects of the field, including the resonant frequencies is increased that some metabolic chains are working more effectively or coherently, and utilize energy to maintain life and healthy function. This is also supported by the fact that people with a smaller BMI have higher negative correlations with LGMF activity which suggest – they are more sensitive to LGMF fluctuations (Table 3 and 4). It is natural that with age and obesity such sensitivity decreases. It is also interesting that found different sensitivities in different genders, that LGMF activity impacts and activates women and mens metabolic chains differently.

5. Conclusions

On the basis of obtained results, we can conclude, that correlations between LGMF and basal metabolic rate features are negative. More expressed negative correlations are seen in persons with smaller BMI. With age negative correlations with LGMF decrease in men group and increase in women group. Sensitivity of persons of different gender to LGMF – differ.