Thermoregulatory physiologic responses in the human body exposed to microwave radiation.

Abstract

By introduction of an additional compartment in the hypothalamic region Stolwijk's thermoregulatory model has been modified to consider partial heating due to hot spots induced by microwaves. It was found that because of thermoregulatory action, the temperature of the hypothalamus will not increase drastically until the rate of energy deposition exceeds the threshold level of about 50 mW/g. The primary controlling mechanisms are blood flow and sweating. For an energy deposition rate of 10 mW/g in the hypothalamus the increase in blood flow in the skin is negligible and the temperature rise of the hypothalamus as compared with blood temperature is about 0.5 degrees C. It was found that exposure of the head to electromagnetic radiation, in general, causes a decrease in temperature of the trunk and skin. The results show that while the deposition of energy in the hypothalamus at the rate of 10 mW/g produced significant conductive and convective effects, the same total energy uniformly distributed over the cranial cavity produces less significant effects.

AI evidence extraction

Main findings

A modified thermoregulatory model incorporating hypothalamic hot spots from microwaves suggested hypothalamus temperature does not increase drastically until energy deposition exceeds ~50 mW/g. At 10 mW/g in the hypothalamus, predicted skin blood flow increase was negligible and hypothalamus temperature rise relative to blood temperature was ~0.5°C; head exposure was associated with decreased trunk and skin temperature, and uniform cranial energy distribution produced less significant effects than localized hypothalamic deposition.

Outcomes measured

• Hypothalamus temperature change
• Thermoregulatory responses (blood flow, sweating)
• Trunk and skin temperature changes
• Conductive and convective heat transfer effects

Limitations

• Modeling study (modified Stolwijk thermoregulatory model) rather than direct experimental measurements
• Microwave exposure parameters such as frequency, duration, and SAR were not specified in the abstract
• Findings depend on assumptions about hot-spot deposition and thermoregulatory mechanisms

{
    "study_type": "other",
    "exposure": {
        "band": "microwave",
        "source": "head exposure (electromagnetic radiation)",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": "human body (thermoregulatory model)",
    "sample_size": null,
    "outcomes": [
        "Hypothalamus temperature change",
        "Thermoregulatory responses (blood flow, sweating)",
        "Trunk and skin temperature changes",
        "Conductive and convective heat transfer effects"
    ],
    "main_findings": "A modified thermoregulatory model incorporating hypothalamic hot spots from microwaves suggested hypothalamus temperature does not increase drastically until energy deposition exceeds ~50 mW/g. At 10 mW/g in the hypothalamus, predicted skin blood flow increase was negligible and hypothalamus temperature rise relative to blood temperature was ~0.5°C; head exposure was associated with decreased trunk and skin temperature, and uniform cranial energy distribution produced less significant effects than localized hypothalamic deposition.",
    "effect_direction": "mixed",
    "limitations": [
        "Modeling study (modified Stolwijk thermoregulatory model) rather than direct experimental measurements",
        "Microwave exposure parameters such as frequency, duration, and SAR were not specified in the abstract",
        "Findings depend on assumptions about hot-spot deposition and thermoregulatory mechanisms"
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "microwave radiation",
        "thermoregulation",
        "hypothalamus",
        "hot spots",
        "energy deposition",
        "blood flow",
        "sweating",
        "head exposure",
        "temperature"
    ],
    "suggested_hubs": []
}

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