Heated vests are garments with integrated, flexible heating elements, typically powered by a rechargeable lithium-ion battery pack. They have gained popularity for providing targeted warmth in cold environments. When manufactured and used correctly, modern heated vests are generally safe due to integrated safety features. However, like any personal electronic device, users must understand potential hazards to ensure a risk-free experience.
Electrical and Component Failure Hazards
The primary electrical risks stem from the integrated power system and heating elements; vests operate on low-voltage direct current, minimizing the danger of electric shock under normal conditions. The true hazard lies in component malfunction, particularly concerning the lithium-ion battery. Manufacturing defects or physical damage can lead to a short circuit within the wiring, causing localized overheating. A damaged battery can enter thermal runaway, where its internal temperature increases uncontrollably, leading to fire or explosion, a risk significantly higher in uncertified products or when the vest has been heavily damaged, such as by bending, crushing, or exposure to moisture.
Thermal Injury Risks to the Skin
Beyond component failure, the heating elements can cause thermal injury to the skin, even when the vest is functioning as intended. High-temperature burns occur if the vest is set too high or used directly against bare skin without a protective layer of clothing. However, a more subtle and common risk is the low-temperature burn, which occurs over a prolonged period of exposure. Cell necrosis, or tissue death, can begin with exposure to temperatures as low as 45°C (113°F) for an hour, which may not feel immediately painful. Chronic exposure to moderate heat can lead to a skin condition called Erythema ab igne, or “toasted skin syndrome.” This presents as a mottled, net-like, hyperpigmented rash that can become permanent if the heat source is not removed.
Health Conditions Requiring Caution
Certain health conditions require users to exercise caution, as the vest’s heat output may pose unique risks.
Individuals with diabetic peripheral neuropathy have reduced nerve sensation, making them unable to detect when the vest is becoming dangerously hot. This sensory impairment significantly increases the chance of receiving a low-temperature burn without realizing it until severe tissue damage has occurred.
For those with implanted medical devices like pacemakers or implantable cardioverter-defibrillators (ICDs), a potential for electromagnetic interference (EMI) exists. The vest’s battery and heating elements can generate EMI that may disrupt the device’s function. Physicians advise keeping the vest’s battery pack and wiring a minimum of 6 inches (15 cm) away from the implant site.
Pregnant individuals should also be cautious, as excessive heat can raise the core body temperature above 38°C (100.4°F). Overheating, particularly in the first trimester, is a medical concern linked to potential developmental issues. Use the vest on a low setting and avoid prolonged use to prevent an increase in internal temperature.
Ensuring Safe Operation and Maintenance
Mitigating the risks of heated vests begins with purchasing a certified product that carries recognized safety marks like UL or CE. These certifications indicate the product has undergone rigorous testing for electrical and thermal safety. Always use the charger and battery pack originally provided by the manufacturer, as using incompatible components can increase the risk of malfunction.
Proper charging protocols are necessary for maintaining battery health and safety. The battery should never be left charging unattended, especially overnight, to prevent fire risk in the event of an electrical failure.
For cleaning, the battery must always be removed before the vest is washed. The vest should be cleaned according to the manufacturer’s instructions, typically using a gentle cycle in a mesh laundry bag, and must only be air-dried. Tumble drying is strictly prohibited, as the heat can damage the internal wiring and heating elements.
When storing the vest for the off-season, disconnect the battery and keep it at a partial charge, approximately 50 to 80% capacity, in a cool, dry place away from heavy objects that could crush the delicate wiring.