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Exposure to the radiofrequency fields generated by mobile phones does not cause head pain or increase blood pressure, according to a Norwegian study.

Instead, people who experience such symptoms do so because they expect that they will occur, the findings suggest.

Dr Gunnhild Oftedal and associates at the Norway University of Science and Technology in Trondheim recruited 17 subjects who "regularly experienced pain or discomfort in the head during or shortly after mobile phone calls lasting between 15 and 30 minutes."

The participants were tested during mobile phone radiofrequency exposure andshamexposure, without knowing which session was which. Each session lasted 30 minutes, and 65 pairs of trials were conducted.

As reported in the medical journal Cephalalgia, the subjects said they felt an increase in pain or discomfort during 68 per cent of all trials. The degree of symptoms was not associated with the order of trials.

The researchers observed no statistically significant correlations between actual exposures and the subjects' reports of symptom severity, and no effects of exposure on changes in heart rate or blood pressure.

Oftedal's team concludes that the most likely explanation for the headaches and discomfort reported by the subjects "is that the symptoms are due to negative expectations."

(Reuters)

挪威一項最新研究表明，置身手機所產生的射頻場不會導致頭痛或血壓升高。

研究結果表明，出現這些癥狀的人主要是因為他們自己覺得會出問題。

挪威科技大學（位于特隆赫姆）的甘赫爾德·奧弗泰德爾博士和他的同事共招募了17名研究對象，這些人“經常在打15至30分鐘電話的過程中或剛打完后出現頭痛或頭部不適癥狀”。

研究人員讓研究對象在不知情的情況下，分別置于射頻場及假性輻射中。每一環節持續30分鐘，共進行了65組試驗。

在醫學雜志Cephalalgia上發表的研究報告表明，在68%的試驗中，研究對象稱感到頭痛或不適癥狀加重。而癥狀的輕重程度與試驗的順序沒有關系。

研究人員并沒有發現置身射頻場與所述癥狀的嚴重程度之間存在明顯的數據上的相關，也沒有發現射頻場對心率與血壓的變化有影響。

奧弗泰德爾博士的研究小組得出結論，對于研究對象頭痛和不適癥狀最合理的解釋應該是“消極的預期。”

（英語點津姍姍編輯）

Vocabulary:

sham:not genuine;something fault or empty（假的；贗品）