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  • Author or Editor: R. Szemerszky x
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Extremely low-frequency electromagnetic field generated by transformer stations located within buildings has been suspected to initiate non-specific health problems. This possibility was examined in model experiments in rats. Following short-term exposure (50 Hz, 500 μT, 20 min), situational and social anxiety as well as locomotor activity pattern were examined by several different tests (elevated plus-maze, novel object exploration, social interaction and territoriality).Based on our results having obtained so far, it seems that these field parameters (that equals the official reference limit for workers) may cause some kind of discomfort, may influence behavior, increase passivity and situational anxiety, but has no verified effect on the social and territorial behavior.

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Impact of 5 mg/kg caffeine, chance of receiving caffeine (stimulus expectancies), and expectations of effects of caffeine (response expectancies) on objective (heart rate (HR), systolic/diastolic blood pressure (SBP/DBP), measures of heart rate variability (HRV), and reaction time (RT)) and subjective variables were investigated in a double-blind, placebo-controlled experiment with a no-treatment group. Participants were 107 undergraduate university students (mean age 22.3 ± 3.96 years). Consumption of 5 mg/kg caffeine had an impact on participants’ SBP, standard deviation of normal heartbeat intervals, HR (decrease), and subjective experience 40 minutes later even after controlling for respective baseline values, stimulus and response expectancies, and habitual caffeine consumption. No effects on DBP, high frequency component of HRV, the ratio of low- and high-frequency, and RT were found. Beyond actual caffeine intake, response expectancy score was also a determinant of subjective experience which refers to a placebo component in the total effect. Actual autonomic (SBP, HR) changes and somatosensory amplification tendency, however, had no significant impact on subjective experience. Placebo reaction plays a role in the subjective changes caused by caffeine consumption but it has no impact on objective variables. Conditional vs deceptive administration of caffeine (i.e. stimulus expectancies) had no impact on any assessed variable.

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Polar watches with heart rate monitoring function have become popular among recreational and professional athletes. In addition to monitoring functions, they calculate a specific index called OwnIndex which is claimed to measure aerobic training status. The current research attempted to shed light on the factors determining the OwnIndex. In Study 1, OwnIndex calculated by the RS-400 Polar watch was estimated using anthropometric (gender, age, height, weight), cardiovascular (resting HR, RMSSD), and exercise-related (maximal oxygen uptake, self-reported physical activity) data of 45 young adults. In Study 2, the OwnIndex was measured in 21 young adults twice, first with self-reported physical activity set to the lowest, then to the highest value. In the regression analysis (Study 1), the only significant predictor of OwnIndex was self-reported physical activity (R2 = 0.883; β = 0.915, p < 0.001). A significant difference with a large effect size (t(20) = −16.657, p <0.001, d = 3.635) and no significant correlation (r = −0.32; p = 0.155) were found between the OwnIndices calculated with different levels of activity in Study 2. As anthropometric and cardiac variables play a practically negligible role in the calculation of the OwnIndex, it cannot be considered an appropriate measure of aerobic fitness.

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