The effects of slight atmospheric pressure fluctuations (APFs) within two ranges of periods attributed mostly to far infrasound (3 s–120 s) and internal gravity waves (120 s–1200 s) on human behaviour related to injury occurrences, within the one-year interval, are examined. Special interest is paid to the analysis of combined effects of APFs and geomagnetic activity (GMA) attributed to low and moderate levels. The relations between the daily number of emergency transport events due to sport injuries (EEI) and daily mean of APF integral amplitudes within the two ranges (DHAI and DHAG, resp.) along with the planetary geomagnetic index Ap are analysed using the regression models based on categorization. As shown, the high DHAI is a rather strong meteorotropic factor, being of relevance to increase in the incidence of sport injuries. The high DHAG appears to be of opposite sense on the background of low DHAI, promoting the decreased EEI number. The consideration of combined effects of the APF and GMA reveals that the negative effects of high DHAI are more pronounced in combination with low Ap levels. The results are discussed from the viewpoint of the necessity of further medico-meteorological studies using databases of most disturbed geophysical conditions.
Numerous studies in medical meteorology indicate that abrupt daily variations in the atmospheric pressure (AP) are important meteorotropic factor rendering adverse effects on health and different kind of human activity. However, insufficient attention is paid to the other bioeffective physical characteristics of AP.
It is known, that variety of atmospheric events make pressure fluctuate in very wide range of periods. Particular interest is the meteorotropic features of the atmospheric pressure fluctuations (APF) in the infrasound frequency range (0.003 Hz <
The important feature of the APF is that they penetrate buildings [
It has also been speculated that the heightened anxiety levels in people with mental disorders increase in suicide incidence and the more frequent occurrences of cardiac arrhythmias on days with strong wind are likely, at least partly, to be due to some biological response to wind-generated rapid atmospheric pressure perturbations [
Our previous study revealed meteorotropic effects of high APF in the far infrasound range concerning people with circulatory system diseases [
The study was conducted in Kyiv city (Ukraine). The continuous measurements of atmospheric pressure, carried out every 0.5 s with a standard high-sensitive (1 Pa) microbarometer (Atmosphere–1, Industrial science-technical cooperative “Dobry shlyah”) outdoors during the same one-year period (from 1 July 2005 to 30 June 2006) as in our previous study [
Three hourly meteorological data on temperature, relative humidity, wind velocity, and atmospheric pressure were received from the Kyiv Geophysical Observatory. Data on planetary geomagnetic activity (Ap index) are available at the Internet (World Data Centre for Geomagnetism, Kyoto).
The database on daily EEI number according to ICD-10 coding rules was obtained from the Kyiv Station of emergency services and medicine of catastrophes. The database includes only the total number of EEI related to professional and amateur sport activities regardless of the kind of sport activity or the severity of injuries.
Within the preprocessing of the EEI one-year database, all public holidays were excluded from the data. Since the EEI and atmospheric data for a few days were not available, altogether 345 days were used for the analysis when 1533 EEI took place. The EEI number proved to be larger on Saturdays than on other days of the week, although the significant difference for EEI was revealed only between Saturdays and Wednesdays (
The EEI number was significantly less in summer than for other seasons of the year (
The EEI number was related to the daily mean of HAI (DHAI) and HAG (DHAG). Since the APFs are causally related to the wind-induced turbulence, the additional analysis of possible association of the DHA effects with wind velocity (WV) was performed in detail. The possible relation between the EEI and geomagnetic activity (GMA), as well as combined effects of APF and GMA, was examined using the daily planetary geomagnetic Ap index [
The mean daily values of temperature, relative humidity, and atmospheric pressure were considered as potential confounding meteorological variables.
A polynomial approximation was used to visually assess the functional form of the relationship between the EEI and the independent variable. The regression models based on categorisation [
All independent variables, as well as the EEI number are not normally distributed. Therefore, non-parametric (Mann-Whitney
Descriptive statistics of variables DHA, WV, and Ap (Table
95% Confidence interval (CI) of DHAI, DHAG, WV, and Ap values, their maximum and minimum values calculated within the one-year interval analysed.
95% CI | Maximum | Minimum | |
---|---|---|---|
DHAI (Pa) | 2.65–3.06 | 11.07 | 0.70 |
DHAG (Pa) | 2.27–2.50 | 10.34 | 0.88 |
WV (m/s) | 2.15–2.37 | 5.50 | 0.00 |
Ap | 8.74–11.23 | 101.87 | 0.00 |
As calculated, the correlation between the yearly profiles of the DHAI and the DHAG values is high (
The yearly dynamics of DHAI and DHAG revealed the pronounced correlation with WV (
The polynomial plot (Figure
95% Confidence intervals (CI) for two categories of DHAI (low and high) values and corresponding EEI number for raw data (EEI/0), data adjusted for the four potential confounding variables (EEI/4), and then additionally adjusted for the DHAG (EEI/4G) (a) along with data on two categories of DHAG (low and high) values with corresponding EEI number for data adjusted for DHAI (EEI/I) and the five potential confounding variables including DHAI (EEI/4I) (b).
(a) | |||
Parameter | Low DHAI CI ( | High DHAI CI ( | |
DHAI (Pa) | 1.81–2.00 | 5.15–5.85 | |
EEI/0 | 3.83–4.48 | 4.81–5.95 | 0.0002 |
EEI/4 | 4.08–4.57 | 4.42–5.32 | 0.028 |
EEI/4G | 4.10–4.57 | 4.42–5.28 | 0.032 |
(b) | |||
Parameter | Low DHAG CI ( | High DHAG CI ( | |
DHAG (Pa) | 1.73–1.82 | 3.18–3.58 | |
EEI/I | 4.36–5.01 | 3.70–4.53 | 0.039 |
EEI/4I | 4.37–4.89 | 3.86–4.54 | 0.032 |
The EEI number (polynomial models) for raw data (dash-dot line) and data adjusted (solid line) for the four potential confounding variables (a), and the DHAI value (b) plotted against the days sorted by DHAI values in ascending order.
After stepwise adjustments for the four potential confounding variables (ND, temperature, relative humidity, and atmospheric pressure), the EEI number remained significantly greater on days in the high DHAI-category when compared to days in the low DHAI-category (Table
The DHAG revealed no effects on the relation between EEI and DHAI. Actually, the high DHAI effect size after additional adjustment for the DHAG remained more or less the same with 11.7% (7.8 to 15.5).
When applying the same analysis to the DHAG variable, no significant relation between the EEI and DHAG was found for the raw data and the data adjusted for the four variables. However, the relation is apparent after the adjustment for either DHAI or for the four variables and DHAI. The corresponding plots for the EEI number adjusted for the DHAI or for the four variables and DHAI (as polynomial function) and the DHAG values obtained in a similar way (as in case for DHAI, Figures
The EEI number (polynomial models) for data adjusted (dash-dot line) for the DHAI and data adjusted (solid line) for the four potentially confounding variables and DHAI (a), and the DHAG value (b) plotted against the days sorted by DHAG values in ascending order.
Possible distorting influence of high DHAI on the EEI versus DHAG relation was proved by the repeated calculations after removing all days with high DHAI from the data. The significant decrease in the EEI number (
On days with the high DHAI, the WV values were also profoundly high (CI: 3.02–3.38 m/s,
A significant, though less pronounced correlation between the DHAG and WV is also mentioned above. However, the effect of high DHAG (when adjusting for the high DHAI) proves to be independent on the WV, since it remains significant (
The same analysis as for the DHA was applied to the Ap variable, and this revealed that the relation between the EEI and Ap is also non-linear implying the threshold effect of higher Ap values. A significant difference in the EEI number is revealed between two categories of Ap values. The first category (CI: 5.00–5.65,
As to the possible combined effects of DHA and Ap variables, the high DHAI (
According to these combinations, the increase in EEI number revealed on days with high DHAI could be related to combined effects of high DHAI and low Ap. By the same token, combined effects of the moderate Ap and low DHAI could be responsible for the decrease in EEI number observed on days with moderate Ap. Actually, these combined effects are confirmed by the facts that the increase in the EEI number on days with high DHAI after additional adjustment for the Ap, as well as the EEI number decrease on days with moderate Ap after additional adjustment for the DHAI, becomes less significant (
Meanwhile, high DHAG and moderate Ap, which both promoted the decrease in the EEI number, were registered mostly on separate days. Therefore, this decrease proves to be no less significant on days with moderate Ap after additional adjustment for the DHAG (
The results of this study provide new evidence on meterotropic effects of high APF in the far infrasound frequency range, namely, their relevance as to the increased risk of sport injuries. Moreover, new information on human sensitivity to APF with periods of internal gravity waves (G-range) is obtained using the database on sport injuries.
According to our analysis, it is reasonable to divide all days of the one-year interval studied into two categories of low and high DHAI, their subintervals of occurrence being about 3/4 and 1/4 of all days considered, respectively. The increased EEI number was documented for high DHAI. However, in spite of the quite wide range of low DHAI values, the EEI number persists to be low without significant changing, which indicates the adequate adaptation of people to such low APF levels in the I-range as to usual and common atmospheric noise. Meanwhile, the high APF in the I-range is a rather strong atmospheric factor resulting in the additional strain for the human adaptation mechanisms. As a consequence, a failure of the adequate behavioural reaction during sport activity is likely to take place, which leads, for example, to the increased EEI number. The non-linear relation between the EEI and DHAI manifested by the threshold effect for high DHAI is apparent. Similar relation was found between the DHAI and emergency transport events coded as circulatory system diseases in a previous study [
The EEI versus DHAG relationship proved to be opposite to that of EEI versus DHAI. Such a peculiarity of effects for two frequency ranges is likely linked to the frequency-dependent human sensitivity, resulting in the distinctive response. According to this, the APF with larger periods as in the G-range is rather a weaker physical factor than APF in the I-range with the same amplitude. It appears that higher DHAG have the activating and mobilizing effects leading to a more successful sport performance and as a consequence the decreased EEI number takes place. However, the high DHAG favourable effect fails to occur under high DHAI conditions when mechanisms of adaptation are already overstrained by this additional physical environmental factor. As revealed, the high DHAI effect prevails and even distorts the EEI versus DHAG relationship. That is the reason why the high DHAG effect is identified only for days with low DHAI or after adjustment for the DHAI variable.
Of interest are also the possible associations of the APF effects on the EEI number with WV, since the strong wind turbulence is the main source of APF. The mechanisms of the strong wind influence on human health and behaviour are not known. Some authors believe that adverse consequences of the strong wind on human health are due to negative effects of environmental concomitants such as ambient temperature, barometric pressure, positive ion concentrations, and so on [
As to the human response, other natural physical environmental variables (e.g., variations of magnetic, electric and gravitational fields) can contribute to combined effects. Namely, the GMA variable related to human health parameters and behaviour is studied recently [
The interval studied corresponds to low solar activity, and, as can be expected, GMA is not pronounced. In fact, mainly days corresponding to the two lowest gradations of Ap values prevail. Meanwhile, the category of moderate Ap values corresponds mostly to the GMA third gradation identified as active geomagnetic condition (16 < Ap < 30). Such levels of GMA can be considered to be the favourable environmental factor from the viewpoint of an adequate adaptation of people (the decreased risk of sport injuries is indicated by the low EEI number). On the other hand, the very low GMA levels appear to be the rather unfavourable factor for human beings. Our analysis shows that the low GMA rather aggravates adverse effects of high APF. It seems that days with simultaneously high APF and low Ap are the most unfavourable, since the relative increase in the EEI number on these days was the highest.
According to a number of studies only extremely high GMA, such as severe magnetic storm conditions are the actual risk for adverse psychophysiological and autonomic reactions of healthy people. However, there was the lack of data on strong GMA levels in this study. Keeping in mind inhibiting effects of severe magnetic storms [
It is believed that natural APF could affect the human body through the ear [
We suggest that APF may influence the inner ear, too. The pressure transmission from the external ear canal to the inner ear is well studied in the otolaryngology. Particularly, it is established that a linear relationship exists between the amplitudes of pressure periodic changes in the inner ear and external ear canal of at least within the +/− 200
It is also shown that vestibular activity is dependent on the rates of ambient pressure changes in the middle ear. It is larger under higher rates of pressure changes [
Vestibular reactions to APF were suggested in previous experimental studies applying replicated barometric pressure oscillations in the infrasound frequency range. Kompanets [
The high APFs during adverse weather usually persist for many hours and even for some days. Such long-term influence of high APF on vestibular system can lead to autonomic and motor disorders and promote unsuccessful sports performance resulting in injury occurrences.
To conclude, the present study provides evidence that APF in the both frequency ranges is a poorly known contributor to human response to weather conditions. It appears that high DHAI is a strong meteorotropic factor associated with the increased EEI number, whereas the high DHAG levels are adequate for human adaptation. We propose that the opposite sense of the DHAI and DHAG relations with the EEI number revealed in the study is, at least partly, a result of dependency of human threshold sensitivity and adaptation ability on the APF frequency ranges.
The results obtained emphasize the importance of a more accurate and detailed analysis of the simultaneous and complex influence of meteorological and geophysical variables such as APF in both ranges of periods and GMA. Particularly, the combined effects of DHAI and DHAG modify the resulting output. Actually, the high DHAI unfavourable effects exert the distorting influence on the relation between the EEI and DHAG. Meanwhile, the low GMA aggravates the adverse effects of high DHAI promoting greater increase in the EEI number. According to our analysis the significant relationship exists between the strong wind and high DHAI effects, which is not the case for the high DHAG effects.
This is only exploratory study, limited by one-year period with low levels of GMA and by the geographical area (Kiev region) with moderate atmospheric conditions, where still or slightly windy weather prevails. The next step is to extend the analysis over a longer period including the time intervals with severe geomagnetic storm conditions and stronger atmospheric perturbations, as well as other geographical areas to receive data of high APF and stormy GMA levels.
This study was supported by the NATO Program Security Through Science, Collaborative Linkage Grant number 98376, funds from the University of Antwerp (BOF-NOI), and Ukrainian-Slovak Joint Research Project, number 7-0810. The authors thank A. V. Vershygora and V. T. Erygina (Kyiv Station of emergency services and medicine of catastrophes) for providing emergency transport events data.