Heated blankets provide warmth through internal wires, but concerns exist about whether this sustained external heat source negatively affects the body’s natural blood flow and circulation. The effect is nuanced, depending largely on a person’s underlying health status and how the blanket is used. For a healthy individual, a heated blanket may actually support circulation. However, for those with specific medical conditions, the device can pose genuine risks to tissue health.
The Body’s Normal Response to External Heat
The human body uses thermoregulation to maintain a core temperature of approximately 98.6°F (37°C). When the skin detects external warmth, the body initiates a cooling response to prevent overheating. This response involves widening the blood vessels near the skin’s surface, a process known as vasodilation.
Vasodilation increases the diameter of small arteries and capillaries, allowing a greater volume of blood to flow into the localized area. This rush of blood to the skin’s surface facilitates heat dissipation, transferring heat from the body to the environment. For most people, this localized increase in blood flow is temporarily beneficial, creating warmth and relaxation.
The systemic effect of widespread vasodilation is a slight, temporary decrease in overall blood pressure, as resistance in the blood vessel network is reduced. This physiological mechanism demonstrates how external heat directly influences the circulatory system. In healthy users, circulation is temporarily enhanced.
Specific Health Conditions That Increase Circulation Risk
The potential for heated blankets to cause harm arises when the body’s natural defense mechanisms are impaired. The most significant risk factor is peripheral neuropathy, often a complication of long-term diabetes, which involves damage to the nerves in the extremities. Individuals with this condition have a reduced or absent ability to sense temperature or pain in their hands and feet. This means they may not register when the blanket is set too high or has created a dangerously hot spot.
This lack of sensation can lead to serious thermal burns and localized tissue damage. Since the skin’s integrity is compromised, the poor circulation typical in diabetes hinders the delivery of immune cells and nutrients necessary for wound healing. A thermal injury can quickly progress to a chronic wound or ulcer due to these underlying circulatory deficits.
Another group at elevated risk includes those with Peripheral Vascular Disease (PVD) or Peripheral Artery Disease (PAD), where blood flow to the limbs is already restricted by narrowed arteries. In these scenarios, the body cannot efficiently move the increased blood flow away from the heated area to cool the tissue. This compromised circulation leads to a buildup of heat in the tissues, significantly increasing the risk of overheating and tissue damage.
Prolonged heat exposure can cause significant sweating and lead to dehydration, which may slightly thicken the blood. For individuals with existing cardiovascular conditions, this increased blood viscosity and the temporary drop in blood pressure from vasodilation can strain the heart. People who are elderly or have mobility issues may also have decreased skin sensitivity and an inability to easily reposition or remove the blanket, compounding the risk of sustained heat exposure.
Guidelines for Safe Heated Blanket Use
To mitigate risks to circulation and tissue health, proper usage of a heated blanket is paramount. Seek blankets certified by a nationally recognized testing agency that feature an automatic shut-off function and a timer. These features prevent the blanket from operating for extended, unattended periods or reaching extreme temperatures.
Use the heated blanket solely for pre-warming the bed before getting in, then turn it off and unplug it before falling asleep. This strategy provides comfort without sustained heat exposure throughout the night. Ensure the blanket is laid flat and never folded, tucked, or bunched up, as this can damage the internal wiring and create concentrated hot spots.
Never combine a heated blanket with other localized heat sources, such as a heating pad. For those with pre-existing conditions like diabetes, PVD, or reduced sensation, consulting a healthcare provider is the most important preventative measure. If you experience redness, persistent irritation, or discomfort, immediately turn off the blanket and discontinue use.