Behavioral and autonomic thermoregulation in mice exposed to microwave radiation.

Abstract

Preferred ambient temperature (Ta) and breathing rate were measured in free-moving mice exposed to 2,450-MHz microwaves. A waveguide-exposure system was imposed with a longitudinal temperature gradient that permitted mice to select their preferred Ta. Breathing rate was determined by analyzing the rhythmic shifts in microwave energy not absorbed by the animal. Without microwave exposure mice selected an average Ta of 31 degrees C. This preferred Ta did not change until the specific absorption rate (SAR) at 2,450 MHz exceeded approximately 7.0 W X kg-1. Mice maintained their breathing rate near baseline levels by selecting a cooler Ta during microwave exposure. In contrast, mice maintained at 31 degrees C underwent a sharp increase in breathing rate when SAR exceeded approximately 7.0 W X kg-1. Mice exposed to microwaves in a waveguide with a temperature gradient increased breathing rate 0.6 breaths/min per unit increase in SAR, whereas without the temperature gradient breathing rate increased by 9.6 breaths/min per unit increase in SAR. Data from this study support previous studies that have shown behavioral thermoregulation is more effective (or efficient) in minimizing a thermal load than autonomic thermoregulation.

AI evidence extraction

Main findings

Mice selected an average ambient temperature of 31°C without microwave exposure, and preferred Ta did not change until SAR at 2,450 MHz exceeded ~7.0 W/kg. During exposure with a temperature gradient, mice selected cooler Ta and kept breathing rate near baseline; when maintained at 31°C, breathing rate increased sharply when SAR exceeded ~7.0 W/kg. Breathing rate increased 0.6 breaths/min per unit SAR with a temperature gradient versus 9.6 breaths/min per unit SAR without the gradient.

Outcomes measured

• preferred ambient temperature (Ta) selection
• breathing rate
• behavioral thermoregulation vs autonomic thermoregulation

Limitations

• Sample size not reported in abstract
• Exposure duration not reported in abstract
• Outcomes limited to thermoregulatory behavior and breathing rate; no other health endpoints described

Suggested hubs

• thermal-effects (0.9)
  Study examines thermoregulation and breathing rate changes at high SAR during 2,450 MHz exposure.
• animal-studies (0.75)
  Experimental exposure study in mice.

{
    "study_type": "animal",
    "exposure": {
        "band": "microwave",
        "source": "waveguide exposure system",
        "frequency_mhz": 2450,
        "sar_wkg": 7,
        "duration": null
    },
    "population": "Free-moving mice",
    "sample_size": null,
    "outcomes": [
        "preferred ambient temperature (Ta) selection",
        "breathing rate",
        "behavioral thermoregulation vs autonomic thermoregulation"
    ],
    "main_findings": "Mice selected an average ambient temperature of 31°C without microwave exposure, and preferred Ta did not change until SAR at 2,450 MHz exceeded ~7.0 W/kg. During exposure with a temperature gradient, mice selected cooler Ta and kept breathing rate near baseline; when maintained at 31°C, breathing rate increased sharply when SAR exceeded ~7.0 W/kg. Breathing rate increased 0.6 breaths/min per unit SAR with a temperature gradient versus 9.6 breaths/min per unit SAR without the gradient.",
    "effect_direction": "mixed",
    "limitations": [
        "Sample size not reported in abstract",
        "Exposure duration not reported in abstract",
        "Outcomes limited to thermoregulatory behavior and breathing rate; no other health endpoints described"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "mice",
        "microwave radiation",
        "2450 MHz",
        "specific absorption rate",
        "SAR",
        "thermoregulation",
        "preferred ambient temperature",
        "breathing rate",
        "waveguide exposure"
    ],
    "suggested_hubs": [
        {
            "slug": "thermal-effects",
            "weight": 0.90000000000000002220446049250313080847263336181640625,
            "reason": "Study examines thermoregulation and breathing rate changes at high SAR during 2,450 MHz exposure."
        },
        {
            "slug": "animal-studies",
            "weight": 0.75,
            "reason": "Experimental exposure study in mice."
        }
    ]
}

Comments

Log in to comment.

No comments yet.