Heated blankets, often called electric blankets, contain integrated electrical heating wires designed to provide warmth and comfort. They are a popular way to stay warm during colder months, often used to pre-heat a bed or provide heat throughout the night. Their widespread use has led to questions about their safety, particularly regarding a potential connection to cancer, stemming from the electromagnetic fields (EMFs) they emit.
Understanding Electromagnetic Fields (EMFs)
The source of public concern regarding heated blankets is the electromagnetic field they generate. Any device that is plugged into a power source and uses an electrical current, including household appliances, produces EMFs. Heated blankets operate using standard Alternating Current (AC) electricity, which creates extremely low-frequency (ELF) electric and magnetic fields.
EMFs are broadly categorized into two types: ionizing and non-ionizing radiation. Ionizing radiation, which includes X-rays and gamma rays, carries enough energy to directly damage DNA and cells, and is known to cause cancer.
The ELF-EMFs emitted by heated blankets fall into the non-ionizing category. This type of radiation lacks the energy required to break chemical bonds or directly damage cellular DNA. The heating elements embedded within the blanket generate these fields as the current passes through, placing the source of the field in direct contact with the body for extended periods.
Evaluating the Scientific Evidence
Major health organizations have thoroughly investigated the potential link between ELF-EMFs, such as those from heated blankets, and cancer risk. The International Agency for Research on Cancer (IARC), which is part of the World Health Organization, has classified ELF-EMFs as “possibly carcinogenic to humans,” placing them in Group 2B. This classification is used when there is limited evidence of cancer in humans and less than sufficient evidence in experimental animals.
The IARC’s classification is primarily based on limited evidence from epidemiological studies suggesting a possible association between high-level residential ELF-EMF exposure from power lines and childhood leukemia. However, this classification is not specific to heated blankets. The National Cancer Institute has stated that no biological mechanism has been identified by which the ELF-EMFs from appliances could cause cancer.
Specific studies focusing on the long-term use of heated blankets have generally found no conclusive evidence of a connection to various cancer types. Investigations into breast cancer risk have not supported the hypothesis that electric blanket use increases the risk, even among women who use them daily or for many years. Similarly, research looking at thyroid cancer risk found no association with the duration or frequency of electric blanket use. The prevailing scientific consensus is that the exposure levels from typical heated blanket use are not considered a significant cancer risk.
Practical Steps for Reducing EMF Exposure
Users can take practical steps to minimize their exposure to the EMFs produced by heated blankets.
The most effective measure is to use the blanket for pre-heating the bed and then turning it completely off before sleeping. This allows the user to enjoy the warmth while eliminating the EMF source during the hours of prolonged contact.
Another strategy is to maintain distance from electrical components, especially the control unit and power cord, as these are often the strongest sources of the field. Consumers can also explore newer models designed for low-EMF emissions. These blankets often feature special wiring that helps to cancel out magnetic fields, significantly reducing the user’s exposure.
Non-EMF Health and Safety Risks
Heated blankets carry other safety and health risks beyond EMF concerns.
The most common physical risk is burns or overheating, which can occur from prolonged exposure to high heat settings. This is particularly concerning for individuals with reduced heat sensation, such as those with diabetes, neuropathy, or circulatory issues.
Improper use or an old, damaged product can also pose a serious fire hazard. Faulty wiring, frayed cords, or folding the blanket in a way that crimps the internal heating elements can cause the blanket to short out and ignite. Modern blankets often include automatic shut-off features to mitigate fire and overheating risks, but older or poorly maintained units lack these safeguards.
A separate concern is the risk of excessive core body temperature increase, especially for vulnerable populations like pregnant individuals. Medical professionals sometimes advise against heated blanket use during pregnancy to avoid increasing the core body temperature to levels that may be harmful. Overheating can also lead to dehydration or heat-related illness in the elderly or small children.