A lightning strike is a rare but destructive event, delivering an instantaneous discharge of immense electrical power to the human body. The current within a single lightning flash can reach hundreds of thousands of amperes, driven by potential differences often exceeding 10 million volts. This massive electrical energy interacts with the body’s delicate biological systems in complex and devastating ways. Understanding how this energy transfers to a person explains the wide range of injuries, from immediate life-threatening crises to chronic, long-term health issues.
The Mechanism of the Strike
The electrical current from a lightning discharge interacts with the human body through several distinct mechanisms, which determine the pattern and severity of the injury. A true direct strike, where a person becomes part of the main discharge channel, is the least common type but is the most likely to be immediately deadly. More frequent are indirect strike mechanisms, such as a side flash, where the current jumps from a nearby taller object, like a tree, to the victim. Ground current is also a common danger, occurring when lightning strikes the earth and the electrical energy radiates outward along the ground surface.
The ground current is often responsible for multiple casualties, as the current can travel up one leg and down the other, creating a voltage difference across the body. A protective factor for survival is the “flashover” effect, where the majority of the current travels over the moist surface of the skin and clothing rather than fully penetrating internal structures. This external path limits damage to internal organs, though some current still travels through the nervous and cardiovascular systems. This rapid discharge lasts only a fraction of a second, but the thermal and electrical shock is sufficient to cause massive biological disruption.
Immediate Systemic Failure and Acute Crisis
The most life-threatening effects of a lightning strike involve the immediate depolarization of the body’s control centers, resulting in abrupt systemic failure. The high-voltage surge can short-circuit the heart’s electrical system, commonly leading to asystole, where the heart stops completely. Although the heart’s natural pacemaker may spontaneously restart after the initial shock, the electrical discharge often simultaneously paralyzes the brain stem’s respiratory control center.
This respiratory paralysis is typically more prolonged than the cardiac arrest, meaning the victim ceases breathing even after the heart has resumed beating. Without continued respiration, the body quickly becomes deprived of oxygen, leading to secondary hypoxic cardiac arrest. This sequence makes immediate cardiopulmonary resuscitation (CPR) a necessary intervention for survival. Furthermore, the powerful electrical force can cause violent muscle contractions, potentially resulting in fractures or joint dislocations.
Physical Manifestations and Localized Trauma
Despite the extreme heat of a lightning channel, serious deep-tissue burns are less common than expected due to the flashover effect and the short duration of the strike. When true burns occur, they are typically superficial, such as linear burns that follow sweat or moisture paths on the skin, or punctate burns where the current enters or exits the body. The explosive force of the superheated air and the shockwave created by the strike frequently causes localized mechanical trauma.
The most common mechanical injury is the rupture of the tympanic membrane (eardrum), which occurs in over half of lightning strike victims due to the sudden, intense pressure change. A unique and temporary sign of a lightning strike is the appearance of Lichtenberg figures, which are fern-like, reddish patterns on the skin. These are not true thermal burns but result from the electrical current causing superficial capillary damage. These distinctive markings typically fade and disappear without treatment within 24 to 48 hours. The eyes are also vulnerable to damage, with cataracts sometimes developing months or even a year after the incident.
Long-Term Neurological and Psychological Consequences
For survivors of a lightning strike, the lasting damage is often concentrated in the central nervous system, leading to chronic and debilitating health issues. The electrical energy can injure the brain and peripheral nerves, resulting in a wide array of long-term neurological problems. Survivors commonly report cognitive deficits, including difficulty with memory, impaired concentration, and slowed reaction time. These “invisible wounds” can significantly interfere with a person’s ability to return to work and maintain a normal social life.
Chronic pain is a frequent consequence, often manifesting as nerve damage syndromes, such as complex regional pain syndrome. Psychological trauma is also prevalent, with many survivors experiencing symptoms similar to post-concussion syndrome, anxiety, depression, and post-traumatic stress disorder (PTSD). Personality changes, including increased irritability and emotional lability, are often reported, which can strain relationships. These persistent health problems affect a large percentage of survivors, with many experiencing ongoing health issues.