When electricity passes through your body, it forces your muscles to contract, heats your tissues, and disrupts the electrical signals your heart and brain depend on. The severity ranges from a brief, painful jolt to life-threatening cardiac arrest, depending on how much current flows, what path it takes through your body, and how long the contact lasts. Even shocks that feel minor can sometimes cause delayed complications that show up hours or days later.
What Happens to Your Muscles
Electricity stimulates muscles and nerves directly. At low levels, you feel a tingling or painful sensation that makes you pull away. But once the current reaches about 10 milliamps of alternating current (the type in household outlets), it triggers what’s called a tetanic contraction: your muscles lock up involuntarily and stay contracted as long as the current flows. This is why people sometimes can’t let go of an electrified wire or tool. The threshold varies from person to person, ranging from 6 to 24 milliamps depending on body composition and the muscles involved.
If the current path runs through your chest, those same sustained contractions can freeze your breathing muscles, cutting off your air supply. Respiratory arrest from chest muscle paralysis is one of the most immediate dangers of electrical contact, even at currents well below what it takes to stop your heart.
How It Affects Your Heart
Your heart runs on its own finely tuned electrical signals. External current disrupts that rhythm. Ventricular fibrillation, where the heart quivers chaotically instead of pumping blood, can occur with exposure to currents as low as 50 to 120 milliamps. For context, a standard household outlet can deliver far more than that. Whether the current actually reaches your heart depends on the path it takes: hand-to-hand or hand-to-foot contact is more dangerous than current passing through a single finger, because the electrical path is more likely to cross the chest.
Heart rhythm problems don’t always appear instantly. Irregular rhythms can develop hours after a shock, which is why hospital monitoring is standard after significant electrical injuries.
Burns You Can and Can’t See
Electrical injuries cause several types of burns. Arc flashes produce intense heat that scorches skin without current actually entering the body, similar to a conventional thermal burn. If a spark ignites clothing, the resulting flame burns add another layer of injury. But the most deceptive damage comes from true electrical injuries, where current passes through the body between entry and exit points.
With true electrical injuries, the skin at the contact points may look relatively minor while the tissues underneath are severely damaged. High-voltage currents (1,000 volts or more) cause deep destruction of muscle, nerves, and blood vessels along the current’s path. The damage often looks far worse on the inside than the outside, which is part of what makes electrical injuries so dangerous to assess.
High-voltage injuries carry higher rates of compartment syndrome (where swelling inside a muscle group cuts off blood flow), extensive tissue death, and in severe cases, limb amputation.
Muscle Breakdown and Kidney Damage
When electricity destroys muscle cells, those cells release their contents into the bloodstream. One of those contents, a protein called myoglobin, is toxic to the kidneys in large amounts. This condition, rhabdomyolysis, develops in roughly 10% of people who survive a significant electrical accident. About one in three people with rhabdomyolysis goes on to develop acute kidney injury as the kidneys struggle to filter the flood of muscle proteins.
Symptoms of rhabdomyolysis include dark or tea-colored urine, muscle weakness, and severe pain. It can develop in the hours and days following a shock, which is one reason electrical injuries often require hospital observation even when initial symptoms seem manageable.
Long-Term Neurological Effects
Nerve damage at the site where current entered the body is extremely common after electrical injury. This can show up as numbness, tingling, weakness, or chronic pain in the affected limb. Damage to multiple nerves throughout the body is also a recognized long-term consequence.
Beyond the physical nerves, electrical injury frequently affects the brain. Survivors commonly report problems with verbal memory, attention, and executive functioning (the ability to plan, organize, and make decisions). Behavioral changes are also well documented. Chronic pain after electrical injury is notoriously difficult to treat. Research shows that many patients are never fully relieved of pain regardless of the treatment approach, though combining physical and psychological therapies produces the best outcomes.
Other delayed complications can emerge weeks, months, or even years later. Cataracts, for example, are a known long-term effect of electrical injury to the head. Mental health conditions including anxiety, depression, and PTSD are also common among survivors of serious shocks.
What Determines How Bad It Is
Several factors control the severity of an electrical injury:
- Current level: The amount of electricity flowing through your body matters more than the voltage. Voltage drives the current, but your body’s resistance (which varies by moisture, skin thickness, and contact area) determines how much current actually passes through.
- Path through the body: Current traveling hand to hand or hand to foot crosses the chest and is more likely to affect the heart and lungs. Current confined to a single extremity is still dangerous but less likely to be immediately fatal.
- Duration of contact: Longer exposure means more energy delivered to tissues, more heating, and more cellular damage. Tetanic muscle contractions that prevent you from releasing the source dramatically increase exposure time.
- Type of current: Alternating current (AC), the kind in wall outlets, is generally more dangerous than direct current (DC) at the same level because it repeatedly stimulates muscles and is more likely to cause the “can’t let go” phenomenon.
What to Do If Someone Gets Shocked
If you see someone receiving an electrical shock, do not touch them while they’re still in contact with the current. You’ll become part of the circuit. Turn off the power source if you can. If you can’t, use a dry, non-conducting object (cardboard, plastic, dry wood) to separate the person from the electrical source. With high-voltage sources like downed power lines, stay at least 20 feet away.
Call emergency services if the person has burns, confusion, difficulty breathing, or any sign of heart rhythm problems. If they’re unresponsive and not breathing, start CPR immediately. Cover any visible burns with sterile gauze or a clean cloth, but avoid towels or blankets because loose fibers can stick to burned skin. Try to keep the person warm while waiting for help.
Even after a shock that seems mild, watch for delayed symptoms over the following hours and days: dark urine, increasing pain, confusion, chest discomfort, or vision changes. These can signal complications developing beneath the surface that weren’t obvious at first.