How electricity affects the human body? An in-depth guide to electrical health risks

October 2, 2025 •

5 min read

The human body is intrinsically bioelectric, relying on electrical signals to control crucial functions like your heartbeat and every muscle contraction. When external electrical current is introduced, however, the consequences can be life-threatening, causing severe burns, cardiac arrest, nerve damage, and other catastrophic injuries.

Quick Summary

Electrical current passing through the body generates heat, causing destructive thermal burns and internal tissue damage. An electric shock can also short-circuit the body's nervous system, leading to muscle paralysis, cardiac arrhythmias, and respiratory arrest, with severity depending on several key factors.

Key Points

Internal Damage Is Key: Electrical current causes deep, internal tissue damage and burns, which may not be visible on the skin's surface.
AC Current Is More Dangerous: Alternating current (AC) can cause sustained muscle contractions, preventing a person from releasing the electrical source and increasing exposure time.
Heart Vulnerability: The heart's electrical rhythm can be fatally disrupted by even a small amount of current, particularly low-frequency AC, leading to ventricular fibrillation.
Nervous System Disruption: Electric shock can short-circuit the body's nervous system, causing immediate or delayed seizures, memory loss, and paralysis.
First Aid Focus: The top priority in an electrical injury is to safely turn off the power source before approaching the victim to avoid becoming a second casualty.
EMF Effects Remain Unproven: The World Health Organization finds no confirmed health consequences from typical, low-level electromagnetic field (EMF) exposure, though research continues.

The body's natural electrical system

Before exploring the dangers of external electricity, it's essential to understand the body's own electrical workings. Your nervous system is a vast network of specialized cells, or neurons, that transmit information via electrical and chemical signals. The electrical signals, known as action potentials, are generated by charged elements like sodium and potassium ions passing through cell membranes. This bioelectrical communication is fundamental for all bodily functions, including voluntary movement, involuntary organ control (like the heart), and conscious thought. Interference with this delicate system is precisely what makes electric shock so dangerous.

How an electric shock damages the body

An electric shock occurs when a person becomes part of an electrical circuit, allowing current to flow through their body. The damage inflicted is determined by a combination of several critical factors:

Intensity of the current: The amount of current (measured in amperes) is the primary determinant of injury severity, not the voltage. The higher the current, the more severe the damage.
Type of current: Alternating current (AC), the type found in household outlets, is generally more dangerous than direct current (DC). AC can cause sustained muscle contractions, freezing the victim to the source and prolonging exposure. AC is also more likely to cause fatal cardiac arrhythmias.
Pathway of the current: The path the electricity takes through the body is crucial. A current passing from arm to arm or through the chest is far more dangerous than one traveling from a leg to the ground, as it is likely to disrupt the heart's rhythm.
Duration of exposure: The longer the body is exposed to the current, the worse the injury. Prolonged exposure increases heat generation and internal damage.
Resistance to the current: The body's main resistance is its skin. Thick, dry skin has high resistance, while wet or broken skin has significantly lower resistance, allowing more current to pass internally and cause more severe organ damage.

Systemic effects of electrical injury

Nervous system damage

Electrical current can interfere with normal nerve signaling, leading to a wide range of neurological issues. Some effects are immediate, while others manifest months or years later.

Central Nervous System: Damage to the brain and spinal cord can cause seizures, memory loss, confusion, personality changes, and difficulty sleeping. High-voltage injuries are known to cause severe, long-term neurological problems.
Peripheral Nervous System: Damage to the nerves in the limbs can result in chronic pain, numbness, tingling, weakness, and paralysis.

Cardiovascular complications

The heart is particularly vulnerable to electric shock because it relies on precise electrical impulses to maintain its rhythm.

Ventricular Fibrillation: Low-voltage AC current, in particular, can disrupt the heart's pacemaker, causing the ventricles to quiver uncontrollably (fibrillate). This is the most common cause of death in electric shock.
Cardiac Arrest: High-current shock can cause the heart to clamp down and stop beating altogether.
Long-Term Effects: Survivors may experience long-term heart problems, including sinus node dysfunction and other arrhythmias.

Muscular and tissue damage

Muscle tissue is severely affected by electric current.

Muscle Contractions (Tetanus): External current can cause powerful, involuntary muscle contractions. This can freeze the victim to the current source or cause them to be thrown clear, leading to secondary injuries like fractures.
Rhabdomyolysis: Massive destruction of muscle tissue from a high-voltage shock releases myoglobin into the bloodstream, which can overwhelm and severely damage the kidneys, leading to acute renal failure.
Internal Burns: While external burns may appear minor, electrical currents can cause significant internal thermal damage to muscles and organs along the current's path. These internal burns can be very difficult to heal.

Electrical injury types and first aid

Different scenarios can lead to electrical injury, each with unique characteristics and appropriate first aid responses. The following table compares common injury types.


Injury Type	Mechanism of Injury	Primary Risk	First Aid Action
True Electrical Injury	Individual becomes part of an electrical circuit.	Internal burns, cardiac arrest, respiratory arrest.	Turn off power source, call 911, start CPR if needed.
Flash Burn	Intense heat from an electrical arc, without current passing through the body.	Skin burns, eye injuries.	Treat burns, get medical help for eye injuries.
Flame Burn	Electrical arc ignites clothing or nearby materials.	Thermal burns from fire.	Extinguish fire, treat burns.
Lightning Strike	Extremely high-voltage, short-duration electrical discharge from a lightning flash.	Multi-system trauma, cardiac arrest, nerve damage.	Call 911 immediately, check for injuries, be aware of secondary trauma.

Regardless of the type of injury, the absolute first step is to ensure the scene is safe. Do not touch a victim still in contact with a live electrical source. Use a dry, non-conductive object to move the source away if power cannot be cut.

Medical applications and EMFs

While external electricity poses clear dangers, controlled electrical energy is a powerful medical tool, known as bioelectronic medicine.

Therapeutic uses include:

Pacemakers and Defibrillators: Regulating abnormal heart rhythms.
Transcutaneous Electrical Nerve Stimulation (TENS): Blocking pain signals for chronic pain management.
Deep Brain Stimulation (DBS): Treating neurological disorders like Parkinson's disease and epilepsy.
Tumor Treating Fields (TT fields): Using electrical fields to inhibit cancer cell multiplication.

Electromagnetic fields (EMFs), emitted by power lines, appliances, and wireless devices, also affect the body, though research into low-level exposure effects is ongoing and inconclusive. Some studies suggest high-level EMFs might induce cellular changes like oxidative stress. However, the World Health Organization states that current evidence does not confirm health consequences from low-level EMF exposure typical of daily life. More information about EMFs and health.

Conclusion

Electricity's effect on the human body is a paradox: it is both an essential component of life and a significant danger when uncontrolled. The severity of an electric shock is not determined by voltage alone, but by a complex interplay of current, duration, and pathway, which can lead to catastrophic damage to the nervous system, heart, muscles, and tissues. While medical science harnesses electricity for healing, it is imperative to respect its power and adhere to strict safety measures to prevent accidental injury. Understanding the mechanisms of both our body's bioelectricity and external electrical hazards is vital for safeguarding our health.

Frequently Asked Questions

Static electricity, while annoying, is generally not dangerous because the current is very low and of short duration. However, in environments with flammable materials or during medical procedures, static sparks can pose a hazard.

Wet skin dramatically lowers the body's electrical resistance. This allows a greater amount of current to flow into the body, causing more extensive internal damage to organs and tissues.

The most dangerous path is one that crosses the chest, particularly if it goes from arm to arm or from an arm to a leg. This pathway is most likely to interfere with the heart's electrical system and cause a fatal arrhythmia.

Yes. While high-voltage shocks cause more severe damage, low-voltage shocks (even under 50V) can be fatal, especially if the current is sufficient to disrupt the heart's rhythm.

An electrical injury refers to any harm caused by an electric current passing through the body. Electrocution specifically refers to a fatal electrical injury.

This is known as 'freezing' and is typically caused by alternating current (AC). The AC stimulates the flexor muscles, causing the hand to clamp down on the conductor, prolonging exposure and increasing the risk of serious injury or death.

Diagnosis involves evaluating the injury's circumstances and performing a physical exam. Doctors may order tests like an EKG to check the heart, blood tests for muscle enzymes, or a CT scan to assess for unseen internal damage.