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Acute effects of 50 Hz magnetic field exposure on human visual task and cardiovascular performance
Author(s) -
Whittington Craig J.,
Podd John V.,
Rapley Bruce R.
Publication year - 1996
Publication title -
bioelectromagnetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.435
H-Index - 81
eISSN - 1521-186X
pISSN - 0197-8462
DOI - 10.1002/(sici)1521-186x(1996)17:2<131::aid-bem7>3.0.co;2-4
Subject(s) - exposure duration , heart rate , medicine , blood pressure , audiology , duration (music) , cardiology , zoology , biology , art , literature , environmental health
One hundred subjects, males and females with ages ranging between 18 and 48 years, were studied under both field‐exposed and sham‐exposed conditions. A 50 Hz, 100 μT magnetic field (MF) was used. To examine the effect of field exposure on performance, a two‐alternative, forced‐choice, duration‐discrimination task with three levels of difficulty was used. The subject's task was to decide which of two sequentially presented light flashes had the longer duration. The standard duration was 50 ms, and the alternative durations were 65, 100, or 125 ms. Both reaction time and percentage of correct responses were recorded for each subject. MF and sham exposure were for 9 min each. Blood pressure and heart rate were also measured before and following MF exposure and sham‐exposure trials. The study was performed double blind, with the exposure order counterbalanced. Compared to sham exposure, MF exposure significantly decreased reaction time on the hardest level of the performance task. MF exposure did not reliably affect percentage correct or cardiovascular performance. It was demonstrated that a relatively high level of statistical power was the basis for the observed MF effect, and the need to pay closer attention to power levels in future research is discussed. © 1996 Wiley‐Liss, Inc.