Electric Shock: What Happens When Current Passes Through Your Body

What Is an Electric Shock and How Does It Affect the Body?

An electric shock occurs when electrical current passes through the body, potentially damaging the heart, nerves, muscles, and other tissues. The severity depends on current strength (amperage), voltage, duration of contact, the pathway through the body, and whether the skin is wet or dry. Even low-voltage household current can be fatal under the right conditions.

When electric current enters the body, it follows the path of least resistance, which typically includes blood vessels, nerves, and muscles because they contain more water and electrolytes than bone or fat tissue. The current can disrupt the heart's electrical system, cause muscle contractions that prevent you from releasing the source, and generate heat that burns internal tissues.

The human body has natural electrical resistance, primarily from the skin. Dry skin provides significant resistance (1,000-100,000 ohms), but wet skin dramatically reduces this protection to as low as 1,000 ohms. This is why electrical accidents in bathrooms, kitchens, or during wet conditions are particularly dangerous.

Understanding the physics helps explain why some electrical contacts are more dangerous than others. According to Ohm's Law (Current = Voltage / Resistance), lower skin resistance means higher current flow at the same voltage. A 120-volt outlet that causes only a tingle on dry hands could deliver a lethal shock to wet hands or through broken skin.

Factors That Determine Injury Severity

Several critical factors determine how severely an electric shock will affect the body. Understanding these factors helps explain why two people can experience very different outcomes from seemingly similar electrical contacts.

Current strength (amperage) is the most important factor. Current as low as 1 milliampere (mA) can be felt, while 10-20 mA causes muscle contractions that may prevent releasing the source ("let-go threshold"). Current of 100-200 mA passing through the heart can cause ventricular fibrillation, the most common cause of death in electrical injuries.

Duration of contact directly affects tissue damage. A brief shock of less than one second, as typically occurs when you touch a faulty appliance and instinctively pull away, usually causes minimal injury. Prolonged contact of one second or more allows more current to flow and more tissue damage to occur.

Current pathway through the body determines which organs are affected. Hand-to-hand current passes directly through the heart and is most likely to cause cardiac arrest. Hand-to-foot pathways also cross the heart. Foot-to-foot pathways, while still dangerous, are less likely to cause immediate cardiac problems.

Contact surface area affects current density. A small point of contact concentrates current and causes more localized burns, while a larger contact area distributes current and may cause more widespread internal damage.

What Are the Different Types of Electric Shock?

Electric shocks are classified as low-voltage (under 1,000V) or high-voltage (over 1,000V) injuries. Low-voltage shocks typically occur at home from faulty appliances or outlets and usually cause less severe injuries. High-voltage shocks from power lines, industrial equipment, or lightning cause severe burns, cardiac arrest, and extensive internal damage.

Low-Voltage Electrical Injuries

Low-voltage injuries occur most commonly in homes and involve household appliances, extension cords, outlets, and light fixtures operating at standard household voltage (110-240V depending on country). These injuries are the most frequent type of electrical accident but are generally less severe than high-voltage injuries.

Most low-voltage injuries result from contact lasting less than one second. The body's protective reflexes cause an involuntary muscle contraction that pulls the person away from the source. Additionally, ground fault circuit interrupters (GFCIs) in modern homes detect current imbalances and disconnect power within milliseconds, limiting injury severity.

However, low-voltage injuries should never be dismissed as minor. Certain circumstances can make household current lethal: wet conditions, contact with grounded metal (like a sink), prolonged contact due to muscle "freeze," or current pathways through the heart. Children and elderly individuals may be more susceptible to serious effects.

High-Voltage Electrical Injuries

High-voltage injuries involve contact with power lines, industrial electrical systems, or lightning, typically exposing victims to thousands or tens of thousands of volts. These injuries are far more likely to be fatal and cause severe, widespread damage even in survivors.

The massive energy in high-voltage contact causes extensive burns at entry and exit points, deep tissue destruction along the current pathway, and explosive effects as moisture in tissues vaporizes instantly. Victims may be thrown considerable distances by the explosive force or by intense muscle contractions.

Lightning strikes represent a unique category of high-voltage injury. Although lightning involves millions of volts, the extremely brief duration (microseconds) and surface flashover effect can allow survival in some cases. However, lightning still kills approximately 20% of victims and causes severe injuries in many survivors.

Static Electricity

Static electricity shocks, though startling and uncomfortable, rarely cause injury. These occur when accumulated electrical charge discharges suddenly, such as after walking on carpet or removing synthetic clothing. The voltage can be very high (up to 25,000V), but the current and duration are so minimal that no tissue damage occurs.

What Are the Symptoms of an Electric Shock Injury?

Symptoms of electric shock range from minor tingling and brief pain to severe burns, muscle spasms, breathing difficulties, irregular heartbeat, and loss of consciousness. Warning signs requiring emergency care include difficulty breathing, chest pain, confusion, burns at entry or exit points, and any loss of consciousness.

Immediate Symptoms After a Mild Shock

A mild electric shock, such as from a faulty appliance or static electricity, typically causes immediate but temporary symptoms. You may feel pain at the contact point that spreads to the surrounding area, along with numbness or tingling. The area may appear red or slightly swollen. These symptoms usually resolve within minutes to hours.

Fear and anxiety are normal responses to any electric shock, even mild ones. The startle reflex may cause you to cry out or jump. Your heart may race temporarily from the adrenaline surge rather than from electrical effects on the heart itself.

Symptoms of Serious Electrical Injury

Serious electrical injuries produce more severe and persistent symptoms that require immediate medical attention. Recognizing these symptoms is critical because internal damage may be far more extensive than visible injuries suggest.

Burns appear at current entry and exit points. Electrical burns often look deceptively minor on the surface while causing extensive deep tissue damage underneath. Entry wounds are typically small and dry, while exit wounds may be larger and more explosive-looking.

Cardiac symptoms include irregular heartbeat (arrhythmia), racing heart, chest pain or pressure, and in severe cases, cardiac arrest. The heart's electrical conduction system is extremely sensitive to external electrical current, and disturbances may occur immediately or develop over the following hours.

Neurological symptoms range from confusion and disorientation to seizures and loss of consciousness. Current passing through the brain can cause immediate unconsciousness. Survivors may experience memory problems, difficulty concentrating, and personality changes.

Muscular symptoms include severe muscle pain, weakness, and involuntary contractions. Severe muscle damage (rhabdomyolysis) releases myoglobin into the bloodstream, which can cause kidney failure if not treated promptly. A warning sign is red-brown urine.

• Loss of consciousness: Even brief unconsciousness requires emergency evaluation
• Difficulty breathing: May indicate respiratory muscle damage or lung injury
• Irregular or rapid heartbeat: Sign of cardiac electrical disturbance
• Visible burns: Entry and exit wounds indicate significant current flow
• Muscle weakness or pain: May indicate rhabdomyolysis risk
• Red-brown urine: Emergency sign of muscle breakdown
• Confusion or memory problems: Indicates current through the brain

Delayed Symptoms

One of the most challenging aspects of electrical injuries is that significant symptoms may not appear until days, weeks, months, or even years after the incident. These delayed symptoms result from progressive nerve damage that wasn't immediately apparent.

Chronic pain at or near the injury site may develop gradually. This can range from constant dull aching to intermittent sharp, burning, or shooting pain. The pain may worsen over time rather than improve.

Sensory changes include reduced ability to feel temperature, touch, or pain in affected areas. Paradoxically, some people develop hypersensitivity to touch or temperature. Cold intolerance and circulation problems (similar to Raynaud's phenomenon) may occur.

Psychological effects are common and often underrecognized. Depression, anxiety, post-traumatic stress disorder (PTSD), and cognitive difficulties including memory and concentration problems affect many electrical injury survivors.

Other delayed symptoms may include low blood pressure problems causing dizziness when standing, bladder dysfunction, sexual dysfunction in men, and coordination difficulties.

When Should You Seek Emergency Care?

Seek emergency care immediately after any electric shock that caused loss of consciousness, breathing difficulties, irregular heartbeat, visible burns, or confusion. Also seek emergency care if you have a pacemaker or implantable defibrillator, if the shock was from a high-voltage source, or if you're unsure about the severity of the incident.

Most people do not need medical attention after a minor static shock or brief contact with household current that caused only momentary discomfort with immediate full recovery. However, when in doubt, it's always better to seek evaluation.

Call Emergency Services Immediately If:

Certain situations require calling your local emergency number (such as 911, 112, or 999 depending on your country) without delay. Time is critical in these circumstances.

Seek Urgent Medical Care If:

Some situations may not require calling emergency services but still warrant same-day medical evaluation. Visit an urgent care center or emergency department for:

• Uncertainty about what happened or severity of the exposure
• Persistent pain, numbness, or tingling beyond 30 minutes
• Any symptoms that concern you
• Contact lasting more than one second
• Shock occurring while in water or wet conditions

Follow-Up Care

Even after initial evaluation shows no serious injury, follow-up care is important. Contact your doctor if symptoms that resolved begin returning, if new symptoms develop, or if symptoms worsen over time. Document the incident in your medical records so that any delayed symptoms can be properly attributed.

How Do You Help Someone Who Has Had an Electric Shock?

First, ensure your own safety - never touch someone who may still be in contact with an electrical source. Disconnect the power if possible, or use a non-conducting object to separate them from the source. Once safe, call emergency services and begin CPR if the person is not breathing normally.

Step 1: Ensure Your Own Safety

This is the most critical step. Rushing to help without ensuring the electrical source is disconnected can result in you becoming a second victim. If the person is still touching the electrical source, you could receive a shock by touching their skin, as current would flow through both of you.

Assess the scene quickly. Look for the electrical source. Is it a household appliance, power tool, or power line? Can you safely disconnect it? Never approach downed power lines or high-voltage equipment - stay at least 35 feet (10 meters) away and call emergency services.

Step 2: Disconnect the Power Source

If the shock involves household current and you can safely access the power source, disconnect it immediately. Unplug the device from the wall outlet, or turn off the circuit breaker if you know which one controls the circuit. The main power switch for the building is the surest option if you're unsure.

If you cannot disconnect the power, you must separate the person from the source without touching their skin. Use a non-conducting object such as a dry wooden board, dry rope, dry clothing, or a dry plastic chair to push or pull the person away. Never use anything wet, metal, or damp.

Step 3: Call Emergency Services

Once the person is free from the electrical source, call your local emergency number immediately. Even if the person appears fine initially, internal injuries may not be apparent, and cardiac monitoring is often needed.

When calling emergency services, provide the following information:

• Your exact location
• What happened (electrical shock)
• The person's current condition (conscious/unconscious, breathing/not breathing)
• Whether the source was low-voltage or high-voltage
• Any visible injuries

Step 4: Provide Emergency Care

Check if the person is responsive by tapping their shoulders and asking loudly if they're okay. If they respond, help them lie down and keep them warm while waiting for emergency services. Monitor their condition for any changes.

If the person is unresponsive or not breathing normally, begin CPR immediately. Push hard and fast on the center of the chest at a rate of 100-120 compressions per minute. If you're trained in rescue breathing, provide 30 compressions followed by 2 breaths. Continue until emergency services arrive or the person regains consciousness.

If an automated external defibrillator (AED) is available, use it as soon as possible. AEDs are designed to be used by anyone and provide voice instructions. They can restore normal heart rhythm in victims of cardiac arrest.

Step 5: Care for Burns and Other Injuries

While waiting for emergency services, you can provide basic first aid for burns if the person is conscious and stable. Cover burns loosely with a sterile bandage or clean cloth. Do not apply ice, butter, or ointments. Do not break blisters.

If the person is conscious, keep them lying down and cover them with a blanket to prevent shock. Elevate their legs slightly if no spinal injury is suspected. Stay with them and provide reassurance until help arrives.

What Happens Inside the Body During an Electric Shock?

Electric current affects all tissues it passes through, causing different types of damage depending on the pathway. The heart can develop life-threatening rhythm disturbances, muscles can be damaged severely enough to release toxins that harm the kidneys, nerves can suffer progressive damage that causes delayed symptoms, and burns can occur both on the skin surface and deep within tissues.

Effects on the Heart

The heart is exquisitely sensitive to electrical current because it relies on its own carefully coordinated electrical signals to maintain a regular rhythm. External electrical current can disrupt this delicate system in several ways.

Ventricular fibrillation occurs when current passing through the heart causes the ventricles (main pumping chambers) to quiver chaotically rather than contracting effectively. Without coordinated contractions, no blood is pumped, and death occurs within minutes unless defibrillation restores normal rhythm.

Asystole (complete absence of heartbeat) can occur with very high current that essentially "stuns" the heart, stopping all electrical activity. This is less common than fibrillation with household current but more common with high-voltage or lightning injuries.

Arrhythmias (abnormal rhythms) may develop immediately or in the hours following a shock. This is why cardiac monitoring is recommended even when victims initially appear fine. Common arrhythmias include atrial fibrillation, premature ventricular contractions, and various conduction blocks.

Effects on Muscles

Muscles contract forcefully when electrical current passes through them. This can be powerful enough to break bones or dislocate joints. The tetanic (sustained) contraction may prevent victims from releasing the electrical source, prolonging exposure.

Rhabdomyolysis occurs when severe muscle damage releases the protein myoglobin into the bloodstream. In large quantities, myoglobin can clog the kidneys, causing acute kidney failure. This is a particular concern with high-voltage injuries and is indicated by dark red-brown urine.

Effects on Nerves

Nerves are particularly vulnerable to electrical injury, and damage may be progressive even after the initial event. Current passing through nerves can cause immediate effects (numbness, weakness, paralysis) and delayed effects (chronic pain, sensory changes, psychological problems).

The delayed neurological symptoms that many electrical injury survivors experience are believed to result from a complex process of progressive nerve degeneration that continues for months or years after the initial injury. This explains why new symptoms can appear long after victims think they have fully recovered.

Effects on Skin and Other Tissues

Electrical burns differ from thermal burns in important ways. The skin's resistance converts electrical energy to heat, causing entry and exit wounds. However, the skin often acts as the highest resistance point, meaning deeper tissues may be more severely damaged than the skin appearance suggests.

Internal electrical burns can damage blood vessels (leading to clots and later bleeding), bones, organs, and any other tissue along the current's path. The full extent of internal damage may not become apparent for days.

How Are Electrical Injuries Diagnosed and Evaluated?

Medical evaluation of electrical injuries includes a complete physical examination, ECG monitoring for cardiac rhythm disturbances, blood and urine tests to detect muscle damage and kidney function, and sometimes imaging studies. Continuous cardiac monitoring may be required for several hours even when initial tests are normal.

Physical Examination

The doctor will perform a thorough physical examination, paying particular attention to:

• Cardiac assessment: Listening to heart sounds, checking pulse rate and rhythm, measuring blood pressure
• Skin examination: Looking for entry and exit wounds, burn patterns, other injuries
• Neurological assessment: Testing sensation, movement, reflexes, and mental status
• Musculoskeletal assessment: Checking for fractures or dislocations from muscle contractions or falls

Diagnostic Tests

Electrocardiogram (ECG/EKG) is essential for all but the most trivial electrical injuries. It detects abnormal heart rhythms and can show damage to heart muscle. Continuous cardiac monitoring for 12-24 hours may be recommended for moderate to severe injuries.

Blood tests include cardiac markers (troponin) to detect heart muscle damage, creatine kinase (CK) to assess overall muscle damage, and kidney function tests. Complete blood count and electrolytes are also checked.

Urine tests check for myoglobinuria (myoglobin in urine), which indicates significant muscle damage and kidney injury risk. Dark or tea-colored urine is a visual warning sign.

Imaging studies may include X-rays to check for fractures, CT scans if internal injuries are suspected, or MRI in certain cases to evaluate soft tissue damage.

Specialist Evaluations

Depending on the injuries, various specialists may be involved in care:

• Cardiologist: For significant cardiac rhythm disturbances
• Neurologist: For neurological symptoms or nerve damage
• Burn surgeon: For significant electrical burns
• Ophthalmologist: Electrical injuries can cause cataracts
• Psychiatrist/Psychologist: For psychological effects including PTSD
• Physical therapist: For rehabilitation

How Are Electrical Injuries Treated?

Treatment depends on the specific injuries and may range from simple observation to intensive care. Key priorities include stabilizing heart rhythm, preventing kidney damage from muscle breakdown, treating burns, and managing pain. Long-term follow-up is important because delayed symptoms are common.

Emergency Treatment

Immediate emergency treatment focuses on life-threatening conditions. Cardiac arrest is treated with CPR and defibrillation. Unstable heart rhythms may require medications or cardioversion. Severe burns require fluid resuscitation and specialized wound care.

If rhabdomyolysis is suspected, aggressive intravenous fluid administration helps flush myoglobin through the kidneys and prevent kidney failure. Urine output is closely monitored, and additional interventions may be needed if kidney function declines.

Hospital Care

Many electrical injury patients require hospital admission for monitoring, even if they appear stable initially. Cardiac monitoring continues for at least 12-24 hours for moderate injuries and longer for severe injuries or those with abnormal initial ECGs.

Burn care for electrical burns follows general burn treatment principles but requires awareness that internal damage may be more severe than surface wounds suggest. Surgical intervention may be needed for deep burns or to release pressure from swelling (fasciotomy for compartment syndrome).

Pain Management

Pain management is an important component of care, both acutely and in the long term. Various approaches may be used depending on pain type and severity:

• Over-the-counter pain relievers for mild pain
• Prescription pain medications for moderate to severe pain
• Nerve pain medications (gabapentin, pregabalin) for neuropathic pain
• Physical therapy
• Specialized pain management techniques

Psychological Support

Psychological effects of electrical injury are common and should not be overlooked. Counseling, psychotherapy, and sometimes medication may help with depression, anxiety, PTSD, and cognitive difficulties that can follow electrical injury.

How Can You Prevent Electrical Injuries?

Prevent electrical injuries by installing and testing ground fault circuit interrupters (GFCIs), never using electrical devices near water, replacing damaged cords and outlets, keeping electrical devices away from children, and following electrical safety guidelines in workplace settings.

Home Electrical Safety

Most household electrical injuries can be prevented with proper precautions and maintenance:

• Install GFCIs in bathrooms, kitchens, laundry rooms, garages, and outdoor outlets. Test them monthly.
• Replace damaged cords immediately - never use tape to repair frayed wires.
• Don't overload outlets with multiple power strips or adapters.
• Keep electrical devices away from water - never use a phone, radio, or hair dryer near a bathtub or sink.
• Use three-prong plugs and never remove the grounding pin.
• Have a qualified electrician inspect and repair electrical problems.

Child Safety

Children are particularly at risk for electrical injuries. Protect them by:

• Installing tamper-resistant outlet covers
• Keeping cords out of reach
• Teaching children about electrical dangers as soon as they're old enough to understand
• Supervising children near any electrical devices
• Never allowing children to insert objects into outlets

Workplace Electrical Safety

Workplace electrical injuries can be prevented by following occupational safety guidelines, using proper personal protective equipment, never working on live electrical systems without proper training and equipment, and reporting electrical hazards promptly.