Exercise testing in the evaluation of human responses to powerline frequency fields.
The present study used exercise testing to examine the effects of 60-Hz electric and magnetic field exposure. Eleven males, 21-29 years, were tested during four experimental sessions (counterbalanced order and double-blind design). These included either 45-min exercise (50% of VO2 max) or no-exercise periods followed by either real field (9-kV/m, 16-A/m) or sham exposure for 2 h in a 60-Hz human exposure facility. Exercise produced a decrease in plasma volume and increases (p less than 0.05) in lactic acid, cortisol, growth hormone and testosterone levels, but these were not different under real and sham field conditions during the 2-h recovery periods. During no-exercise sessions, cardiac interbeat interval was increased (p less than 0.05), i.e., heart rate was slower, when subjects were exposed to real fields. Our results suggest that future studies should focus on evaluation of the effects of 60-Hz fields on the entire process of exercise-induced activation and recovery.
Maresh
C M
CM
BioOrganic Chemistry Department, Midwest Research Institute, Kansas City, Missouri.
Cook
M R
MR
Cohen
H D
HD
Graham
C
C
Gunn
W S
WS
D000328:Adult; D001810:Blood Volume; D002986:Clinical Trials as Topic; D004311:Double-Blind Method; D004574:Electromagnetic Fields / Q000009:adverse effects*; D055590:Electromagnetic Phenomena / Q000009:adverse effects*; D004734:Energy Metabolism; D005080:Exercise Test; D013006:Growth Hormone / Q000097:blood; D006339:Heart Rate; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007773:Lactates / Q000097:blood; D019344:Lactic Acid; D008297:Male; D010100:Oxygen / Q000097:blood; D013739:Testosterone / Q000097:blood
D007773:Lactates; D019344:Lactic Acid; D013739:Testosterone; D013006:Growth Hormone; D010100:Oxygen; D006854:Hydrocortisone