According to Katherine Neer of HowStuffWorks, there are several ways a person can be affected by lightning, each with different impacts. Direct strike, wherein a cloud-to-ground lightning directly hits a person or something he is holding, is the most fatal. In this case, the full impact of lightning courses through the person’s body.
In a side flash, lightning hits something nearby and then moves to the person. After striking the object, the lightning’s current travels through the point of contact into the body. These types of strikes also cause severe impact, although lesser than a direct strike.
The respiratory, nervous and circulatory systems are often affected when a person is hit by lightning. Neer further mentions that the majority of fatalities due to direct strike involve cardiac arrest. Additionally, paralysis is the biggest threat to the respiratory system. In some cases, the victim needs artificial respiration to survive. Impact on the central nervous system leads to several side effects, such as temporary paralysis, amnesia, dementia, memory gaps, impaired reflexes and depression.
According to Professors Steve Ackerman and Jim Knox from University of Wisconsin-Madison, lightning kills around 93 people and injures approximately 300 people on average in the United States every year. The National Oceanic & Atmospheric Administration National Severe Storms Laboratory states that positive lightning is generally more dangerous than negatively charged bolts because it has a stronger electrical field and longer flash duration.