20 volunteers participated (12 women, 8 men; 25 ± 3.9 years). The exposure and sham exposure sessions were performed in random order.
A heat challenge was performed 25 minutes after the end of exposure by locally heating both sides of the face to 44°C for 1 minute, followed by a 30 minute period for the return to baseline. This hyperthermia induced local hyperaemia, which reflects the skin microvessels' ability to dilate in response to heating.
|Exposure duration||continuous for 20 min|
|Duty cycle||12.5 %|
|Setup||"radiofrequency" or "sham" mobile phone was positioned against the left ear (using a helmet-like holder); phone was placed with its long axis aligned from the opening of the ear canal to the corner of the mouth|
|Sham exposure||A sham exposure was conducted.|
|Additional info||room temperature was kept constant at 24 ± 0.6°C|
For a given side of the face, the radiofrequency exposure and sham exposure sessions did not differ significantly in terms of the skin microcirculation (according to the results). According to the abstract and discussion however, skin microcirculation increased more during the radiofrequency exposure session (vs. baseline) than during the sham exposure. The sessions (exposure vs. sham exposure) did not differ significantly in terms of the skin temperature time-course response.
When heating the skin locally to 44°C (on both sides of the face at the same time), the early peak value of skin microcirculation (i.e. the raw data after 1 minute) on the exposed side of the face was significantly greater after the radiofrequency exposure session than after the sham exposure session, i.e. the skin microvessels' vasodilatory ability was greater.
The authors conclude, that the data reveal the existence of a specific vasodilatory effect of mobile phone radiofrequency emission on skin perfusion.