Local vasodilator response to mobile phones.

Abstract

OBJECTIVES: The use of mobile phones with the resulting generation of potentially harmful electromagnetic fields (EMF) is the focus of public interest. Heat generation and the activation of the inducible form of nitric oxide (NO) synthase may be possible causes of the biological effects of EMF exposure. We investigated if a mobile telephone conversation can modify skin temperature, NO, and nasal resistance. METHODS: We studied the effect of an EMF (900 MHz) generated by a commercially available cellular phone during a 30-minute telephone conversation on skin temperature, nasal NO measured by chemiluminescence, and nasal minimal cross-sectional area (MCA) measured by rhinometry. Eleven normal subjects (mean age +/- standard error of mean [SEM], 32 +/- 5 y; 10 male) were studied. RESULTS: There was a similar and significant increase in skin temperature of the nostril and occipital area on the same side as the telephone (maximal increase 2.3 +/- 0.2 degrees C at 6 min) as well as a tendency for higher nasal NO levels (maximal increase 12.9 +/- 4.9% at 10 min), whereas the MCA was significantly reduced (maximal decrease -27 +/- 6% at 15 min). Such changes were not recorded when an earpiece was used to avoid the direct exposure to the electromagnetic field. There were no changes in the skin temperature and nasal NO measured on the opposite side to the mobile phone, whereas the MCA was significantly increased (38 +/- 10%). CONCLUSIONS: Exposure to EMF produced by a mobile phone produces biological effects that can be easily measured. Microwaves may increase skin temperature and therefore cause vasodilation and reduce MCA. Further studies are needed to study the long-term effects of mobile phone use and the relation among NO production, vasodilation, and temperature.

AI evidence extraction

Main findings

During a 30-minute 900 MHz mobile phone conversation, skin temperature increased on the same side as the phone (max +2.3 ± 0.2°C at 6 min), nasal NO showed a tendency to increase (max +12.9 ± 4.9% at 10 min), and MCA was significantly reduced (max −27 ± 6% at 15 min). These changes were not recorded when an earpiece was used to avoid direct EMF exposure; on the opposite side, skin temperature and nasal NO did not change while MCA significantly increased (38 ± 10%).

Outcomes measured

• Skin temperature (nostril/occipital area)
• Nasal nitric oxide (NO) levels (chemiluminescence)
• Nasal minimal cross-sectional area (MCA) / nasal resistance (rhinometry)

Limitations

• Small sample size (n=11)
• Short-term exposure only (30 minutes)
• NO change described as a tendency (unclear statistical significance)
• No SAR or detailed exposure characterization beyond frequency and phone use

{
    "study_type": "other",
    "exposure": {
        "band": "RF",
        "source": "mobile phone",
        "frequency_mhz": 900,
        "sar_wkg": null,
        "duration": "30-minute telephone conversation"
    },
    "population": "11 normal subjects (mean age 32 ± 5 y; 10 male)",
    "sample_size": 11,
    "outcomes": [
        "Skin temperature (nostril/occipital area)",
        "Nasal nitric oxide (NO) levels (chemiluminescence)",
        "Nasal minimal cross-sectional area (MCA) / nasal resistance (rhinometry)"
    ],
    "main_findings": "During a 30-minute 900 MHz mobile phone conversation, skin temperature increased on the same side as the phone (max +2.3 ± 0.2°C at 6 min), nasal NO showed a tendency to increase (max +12.9 ± 4.9% at 10 min), and MCA was significantly reduced (max −27 ± 6% at 15 min). These changes were not recorded when an earpiece was used to avoid direct EMF exposure; on the opposite side, skin temperature and nasal NO did not change while MCA significantly increased (38 ± 10%).",
    "effect_direction": "mixed",
    "limitations": [
        "Small sample size (n=11)",
        "Short-term exposure only (30 minutes)",
        "NO change described as a tendency (unclear statistical significance)",
        "No SAR or detailed exposure characterization beyond frequency and phone use"
    ],
    "evidence_strength": "very_low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "mobile phone",
        "EMF",
        "900 MHz",
        "microwaves",
        "skin temperature",
        "vasodilation",
        "nasal nitric oxide",
        "rhinometry",
        "minimal cross-sectional area"
    ],
    "suggested_hubs": []
}

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