A single bolt of lightning is a natural electrical discharge of immense power. A typical strike carries an average of 30,000 amperes of electrical current and millions of volts. While the chance of being struck is low, the consequences of this massive, instantaneous electrical surge on the human body are complex and severe. Understanding how this energy interacts with the body explains the unique medical challenges faced by survivors.
The Paths of Current: How Lightning Enters the Body
Direct contact is the rarest, yet most dangerous, way for a person to be struck. Even in a direct strike, a significant portion of the electrical current often travels over the skin’s surface, a phenomenon known as “flashover.” This external path is encouraged by the skin’s resistance and the extremely short duration of the strike, which prevents the current from fully penetrating the body.
The most common injuries involve indirect contact, where the body is not the primary target. A side flash occurs when lightning strikes a nearby taller object, such as a tree, and a portion of the current jumps through the air to a person standing close by. Injuries can also occur from conduction, which happens when a person is in contact with an object that is struck, such as a fence or plumbing.
The leading cause of injury and death is ground current, or step potential, which affects the largest area. When lightning hits the ground, the electrical energy spreads outward through the earth in a wave. If a person is standing with their feet apart, the voltage difference between their feet can drive a current up one leg and down the other, traversing the lower body. Victims do not need to be directly under the strike to suffer severe injury from this mechanism.
Acute Medical Emergencies Following a Strike
The most immediate danger is the profound effect on the nervous and cardiovascular systems. The massive electrical shock can instantly depolarize the heart muscle, often resulting in immediate cardiac arrest (asystole). In many cases, the heart’s natural pacemaker may spontaneously restart a rhythm shortly after the strike.
A more severe problem is respiratory arrest, which occurs because the electrical current temporarily shuts down the brain’s respiratory center. Since the heart may restart but breathing does not, the lack of oxygen quickly becomes the main threat to life, leading to secondary cardiac arrest. The strike’s accompanying shockwave, created by the superheated air expanding, frequently causes blunt trauma, including fractured bones and ruptured eardrums.
External burns are usually superficial flash burns caused by superheated air or clothing, rather than deep tissue damage from the current itself. A unique, temporary marking known as a Lichtenberg Figure may appear on the skin. These fern-like patterns are not true burns but are caused by the leakage of fluid from damaged capillaries just beneath the skin’s surface.
Lasting Neurological and Sensory Impacts
For survivors, the lasting consequences are primarily neurological, often presenting as a complex, chronic syndrome. Many experience symptoms similar to those following a severe concussion, sometimes termed “lightning brain.” This includes persistent short-term memory deficits, difficulty with multitasking, slowed reaction time, and trouble concentrating.
Chronic pain is common, frequently resulting from damage to the peripheral nervous system or manifesting as chronic headaches. The electrical current’s path can damage the brain and nervous tissue, leading to emotional and psychological changes, such as increased irritability, anxiety, and post-traumatic stress disorder. These injuries often interfere with a survivor’s ability to return to their previous employment and social life.
Sensory organs are also vulnerable to both the electrical current and the blast wave. The eyes can develop cataracts months or years after the incident, and some individuals experience permanent damage to the optic nerve. Auditory damage is frequent, with the concussive force often causing a ruptured eardrum, which may result in permanent hearing loss or persistent ringing in the ears (tinnitus).
Survival Rates and Necessary Immediate Response
The high voltage and current are often counteracted by the strike’s extremely brief duration, which is why approximately 85 to 90 percent of victims survive. Despite this high survival rate, the majority of survivors face long-term health consequences, ranging from chronic pain to neurological deficits.
A person struck by lightning does not retain an electrical charge and is safe to touch immediately. The most important action for a bystander is to promptly begin cardiopulmonary resuscitation (CPR) if the person is not breathing. Because the heart often restarts on its own, the immediate priority is to manually take over the function of the paralyzed respiratory system until medical help arrives.