IEC TR 60479-4:2020

IEC TR 60479-4 ®
Edition 3.0 2020-02
TECHNICAL
REPORT
colour
inside
Effects of current on human beings and livestock –
Part 4: Effects of lightning strokes
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IEC TR 60479-4 ®
Edition 3.0 2020-02
TECHNICAL
REPORT
colour
inside
Effects of current on human beings and livestock –

Part 4: Effects of lightning strokes

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 13.200; 29.020 ISBN 978-2-8322-7888-8

– 2 – IEC TR 60479-4:2020 © IEC 2020
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
3.1 Definitions of technical terms . 7
3.2 Definitions of interactions . 9
4 Basic physics of lightning . 9
4.1 General . 9
4.2 Lightning occurrence . 11
4.3 Lightning flash characteristics . 12
4.4 Primary and secondary injuries . 12
4.5 Summary . 13
5 Interaction of strokes with human beings and livestock . 13
5.1 General . 13
5.2 Strike mechanisms . 14
5.2.1 Description of direct strike . 14
5.2.2 Description of contact voltage . 15
5.2.3 Description of side flash . 16
5.2.4 Description of step voltage . 16
5.2.4 Description of streamer current . 17
5.3 Specific matters regarding body response . 19
6 Effects of lightning strokes on the body of living beings . 20
6.1 General comments on effects on the body . 20
6.2 Comments on specific syndromes . 23
6.2.1 Keraunoparalysis . 23
6.2.2 Burns . 23
6.2.3 Comparison between effects of electric shock derived from electrical
systems and lightning . 24
7 Present considerations of causation . 26
7.1 Under investigation . 26
7.2 Electrical effects . 26
7.3 Thermal, field and radiation effects . 26
7.4 Traumatic injury . 26
7.5 Barotrauma . 27
7.6 Release of hormones . 27
8 Individual and crowd safety procedures . 27
8.1 General – "No place outdoors is safe" . 27
8.2 Individual actions . 27
8.3 Basic principles . 27
8.3.1 General . 27
8.3.2 Individual lightning safety in the outdoors (NOAA recommendations) . 28
8.3.3 Safe practice indoors . 28
8.4 Safety procedures for crowds . 29
Bibliography . 30

Figure 1 – Categorization of lightning types [4] . 10
Figure 2 – High resolution full climatology (HRFC) . 12
Figure 3 – Direct strike. 14
Figure 4 – Direct strike with no flashover and then with flashover . 15
Figure 5 – Contact potential . 15
Figure 6 – Side flash . 16
Figure 7 – Earth potential versus distance from the stroke base – 10 kA stroke, with
earth resistivity 100 Ωm . 17
Figure 8 – Examples of step voltages, assuming a uniform earth of constant resistivity,

and no surface flashover . 18
Figure 9 – Upward streamer . 19
Figure 10 – Current in establishment and in collapse of upward streamer . 19

Table 1 – Lightning injury and physical symptoms [8], [9], [10], [11], [12], [13], [17] . 22
Table 2 – Comparison of electrical and lightning injury [30], [34], [35], [40] . 25

– 4 – IEC TR 60479-4:2020 © IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EFFECTS OF CURRENT ON HUMAN BEINGS AND LIVESTOCK –

Part 4: Effects of lightning strokes

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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The main task of IEC technical committees is to prepare International Standards. However, a
technical committee may propose the publication of a Technical Report when it has collected
data of a different kind from that which is normally published as an International Standard, for
example "state of the art".
IEC TR 60479-4, which is a Technical Report, has been prepared by IEC technical committee
64: Electrical installations and protection against electric shock.
This third edition cancels and replaces the second edition published in 2011. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) lightning occurence and climatory effects around the world are depicted;
b) direct strike description is extended;
c) step voltage effects are expanded;
d) upward streamer explanation is enhanced;

e) other direct or indirect related effects to lightning injuries to the human body are specified;
f) various safety procedures and related possibilities with respect to the personsal danger of
lightning are presented.
The text of this Technical Report is based on the following documents:
Draft TR Report on voting
64/2369/DTR 64/2398/RVDTR
Full information on the voting for the approval of this Technical Report can be found in the
report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60479 series, published under the general title Effects of current on
human beings and livestock, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.

– 6 – IEC TR 60479-4:2020 © IEC 2020
INTRODUCTION
IEC 60479-1 and IEC 60479-2 deal with the effect of electric shock derived from electrical
systems on the bodies of human beings and livestock. This document describes the influence
and effect of electricity in the form of lightning strikes. Lightning current can consist of several
uni-polar and/or bi-polar impulses with different peak values and durations; IEC 60479-2:2019,
Clause 6 does not cover these effects.
The interaction of a lightning stroke with the body is often different from that of electric shock
derived from electrical systems. If the head is struck, the electrical path may include the brain
stem, which includes the respiratory centre.
IEC 60479-2 includes information related to the effects of short duration impulses which extend
to the magnitude and duration of lightning impulses.
It is accepted that more than 70 % of lightning accidents involving humans are not fatal [36],
[47] . Corresponding reliable data for livestock is not known. There is a large variation in
outcome due to different environments, different activities of people and knowledge of first aid
and quality of medical care [40],[47].
It has been necessary, therefore, to create a separate document concerning the special effects
of lightning strokes. The physical behaviour of lightning is shown as a basis. The interaction
with a living body is then described, followed by the ongoing life consequences.

___________
Numbers in square brackets refer to the bibliography.

EFFECTS OF CURRENT ON HUMAN BEINGS AND LIVESTOCK –

Part 4: Effects of lightning strokes

1 Scope
This part of IEC 60479 summarizes the basic parameters for lightning and its variability insofar
as they apply to human beings and livestock.
The possible direct and indirect interactions of strikes with bodies of living beings are indicated.
The resulting effects caused by lightning currents for the organism are described.
This document shows the differences of effects on human beings and livestock due to lightning
strokes versus those effects of electric shocks derived from electrical systems.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60479-1, Effects of current on human beings and livestock – Part 1: General aspects
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60479-1 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1 Definitions of technical terms
3.1.1
lightning flash
electrical discharge of atmospheric origin between cloud and earth consisting of one
or more lightning strokes
3.1.2
lightning stroke
lightning impulse
single electrical discharge in a lightning flash to earth
3.1.3
lightning channel
conducting path of the lightning current

– 8 – IEC TR 60479-4:2020 © IEC 2020
3.1.4
stepped leader
faintly luminous channel of generally less than 10 C of charge with associated branches that
develops in virgin air and progresses towards the earth in discrete steps
3.1.5
return stroke
bright highly visible channel carrying the impulse current of the stroke, which is initiated when
the stepped leader and upward connecting streamers meet to form the channel
3.1.6
upward flash
lightning flash initiated by an upward leader from earth to cloud
3.1.7
continuing current
current with a magnitude of tens to hundreds of amperes and a duration up to hundreds of
milliseconds often following a return stroke
Note 1 to entry Continuing currents with duration in excess of 40 ms are traditionally termed "long continuing
currents".
3.1.8
lightning current
current flowing at the point of strike
3.1.9
current peak value
maximum value of the lightning current
3.1.10
upward streamer
pre-discharge phenomena induced by the stepped leader, one of which will connect with the
stepped leader opening a lightning channel which becomes a lightning stroke
3.1.11
average steepness of impulse current
average rate of change of lightning current within a time interval bounded by the 10 % and 90 %
values of the peak impulse current front
3.1.12
stroke duration
time in microseconds between the time the return stroke exceeds 2 kA and the time to half peak
value on the tail of the current pulse
3.1.13
flash duration
time for which the lightning current flows at the point(s) of attachment
3.1.14
point(s) of attachment
point(s) at which the successful upward streamer was launched
EXAMPLE Object, human or otherwise.
3.1.15
remote earth
ideal earth of zero resistance and zero potential

3.1.16
physical earth
earth as contact by objects
Note 1 to entry The difference between remote earth and physical earth allows the modelling of an earth resistance
between the two, creating ground potential.
3.1.17
lightning ground flash density
measurement of the number of lightning strikes to ground, over a period of one year, per km
3.2 Definitions of interactions
3.2.1
direct strike
interaction whereby the lightning attaches directly to an object (including a living object)
3.2.2
contact voltage
potential difference between contacted points on an object, on which currents generated by a
lightning event are present, or between an accessible point and an independent object
(including earth) which could result in current flow through a living being
Note 1 to entry In some texts this has been referred to as "contact potential" or "touch voltage".
3.2.3
side flash
electric arc between two objects (including living objects), at least one of which is subject to
partial lightning current
3.2.4
step voltage
step potential
potential difference between two points on the earth’s surface due to a lightning stroke current
being conducted through the earth
3.2.5
flashover
electric arc over the surface of an object carrying a significant proportion of the stroke current
3.2.6
streamer current
current, passing through an object, to establish an upward streamer, but which ultimately will
not become a point of attachment
4 Basic physics of lightning
4.1 General
The explanation of the basic physical mechanisms for the onset and the dynamics of lightning
is very complicated. Within a cloud, three layers are recognized, each with identifiable charges
(see Figure 1). They are generated by microscopic charge transfer between soft hail particles
(also called graupel) and ice crystals. The basal layer is normally negatively charged, with the
layers successively positively and negatively charged in ascending order.
Lightning is a transient, high-current discharge whose path length is measured in kilometres. A
lightning flash is a current phenomenon, and not a voltage phenomenon. More correctly, it is a
"charge dumping" phenomenon, which occurs when the increasing electric field between two
statically charged points exceeds a threshold.

– 10 – IEC TR 60479-4:2020 © IEC 2020
Well over half of all flashes occur wholly within the cloud and are called intra-cloud (IC)
discharges. Cloud-to-ground (CG) lightning has been studied more extensively than other forms
of lightning because of its practical importance (for instance, as a cause for injuries and death,
disturbances in power and communication systems, damage to structures and installed
equipment, and the ignition of forest fires). Cloud-to-cloud and cloud-to-air discharges have
begun to be quantified more easily as a result of space and high altitude experimentation.
Upward flashes from a cloud to the ionosphere have also been identified. All discharges other
than those between cloud and ground (CG), are often combined under the general term cloud
discharges.
Four different types of discharges between cloud and earth have been identified (Figure 1).
Negative CG flashes probably account for about 90 % of the CG discharges world-wide, and
less than 10 % of lightning discharges are initiated by a downward-moving positive leader [57].
Ground-to-cloud discharges are initiated by leaders that move upward from the earth. These
upward-initiated flashes are relatively rare and usually occur from mountain peaks and tall man-
made structures [56], [59].
Other important physical parameters of the lightning environment have been characterized.
Examples are the peak current per return stroke, the charge transferred in a return stroke, the
average steepness of impulse current rise, as well as the stroke duration and total flash duration
where there is more than one stroke in a flash.

a) Downward negative lightning b) Upward negative lightning

c) Downward positive lightning d) Upward positive lightning
Figure 1 – Categorization of lightning types [4]
Thunder accompanies lightning and is generated by superheated air at the channel, which
causes air pressure waves.
4.2 Lightning occurrence
Lightning ground flash density data is now available for most world locations. Lightning location
system networks meeting the requirements of IEC 62858 [64] can provide lightning density
information with a median location accuracy for cloud-to-ground strokes better than 500 m
within the interior of the network. It is acknowledged that the data provided by lightning location
networks could underestimate the actual flash density due to multiple earth attachment points
for one-third to one-half of all cloud-to-ground flashes. IEC 62858 has introduced the term N
SG
to identify the number of ground-strike points to represent the effect of the multiple earth
attachment points. It is generally agreed that ground strike density is the most important
parameter in assessing the number of dangerous events per year when conducting a lightning
risk assessment. It is accepted by the scientific community that the location networks more
accurately estimate the occurrence of cloud-to-ground lightning density than empirical
occurrence estimates.
Where lightning location network data is not available, the use of satellite data may be used.
These data represent the most accurate estimations available at the present time. In the past,
empirical relations were derived from an observation of thunderdays, as follows:
13, −2 −1
N = 0,T023  km yr
G
D
found best in South Africa but with wide variation [4];
14, −2 −1
N = 0,01 T  km yr
G
D
-2 -1 -2 -1
found in a survey of 26 countries with N varying from 0,2 km yr to 3,0 km yr and T
G D
-1 -1
varying from 10 days yr to 100 days yr [42];
Prentice [46] recognized that the general form of these empirical equations was
b −21−
N = aT  km yr
GD
It seems empirically justifiable that b ≥ 1, since it is intuitive that the higher the number of
thunderdays, the longer one might expect a storm to last at a given location.
While the use of the thunderday has had substantial currency in the manner shown, the use of
this parameter is no longer current and should not be used in favour of LLS or satellite data.
A thunderday world map is shown in Figure 2.

– 12 – IEC TR 60479-4:2020 © IEC 2020

SOURCE: https://ghrc.nsstc.nasa.gov/pub/lis/climatology/LIS-OTD/HRFC/browse/HRFC_COM_FR_V2.3.2015.png
Figure 2 – High resolution full climatology (HRFC)
NOTE In most areas of the world, an indication of lightning activity can be obtained from observations of lightning
optical transients. Satellite-based sensors respond to all types of lightning with relatively uniform coverage. With
sufficient averaging, optical transient density data provide better estimates of ground flash density than thunder
observations, which have a wide range of relations between ground flash density and thunderstorm hours or
thunderstorm days. There are also regional variations in the ratio of ground flashes (CG) to total flashes (CG + IC).
The ratio of cloud flashes (N ) and ground flashes (N ) has been further estimated, and is a
c G
function of latitude. The measurement has been enhanced by the ability to differentiate cloud
and ground flashes electronically [42].
The relationship is found to be:
N
c
4,,16+ 2 16cos 3λ
( )
N
G
where λ is the latitude (in degrees). The maximum occurs at the equator and decreases with
distance from the equator.
4.3 Lightning flash characteristics
Numerous studies have determined typical values for lightning parameters. Uman and Krider
[57], and Cooray [31] provide one summary of these. The studies are also summarized in the
lightning environment defined in IEC 62305-1:2010, Tables 3 to 5, Table A.1, and Table A.3
[63]. CIGRE Technical Bulletin 549 [65] has conducted a review of recent studies and confirmed
the lightning environment of IEC 62305-1.
4.4 Primary and secondary injuries
The focus of this document is on death and injury to humans and livestock from the various
effects of lightning. Clause 5 will indicate the mechanisms by which lightning derived current
can impinge on a victim, and Clause 6 will indicate a number of the likely symptoms of injury
seen as a consequence. These are purely due to the electric current and may be thought of as
primary lightning injuries.
Another group of injuries may however be seen and are regarded as secondary to a lightning
strike. This occurs when a lightning strike damages a nearby inanimate object, and the damage
inflicted on these then causes consequent injury to a human being. Protection of structures
from examples of possible secondary injury follows. The means of protection of inanimate
=
objects, including electronic equipment, is a wide science and is examined in detail in
IEC 62305 (all parts) [62].
Rocket triggered lightning experiments provide an experimental vehicle for examining these.
Their experiments are represented in the following:
• Overhead power distribution line damage, where overhead power lines become conduits for
impulses to be transmitted inside a building. Fires may result, and equipment damage may
be seen. Secondary burns and trauma may result.
• Direct strike damage: Mechanical destruction of inanimate objects may cause trauma from
fragmentation and “missiles” thrown toward nearby individuals.
• Underground cables: Surges into a dwelling may result causing similar damage to the first
case above.
Similarly, communication cable entry to dwellings may cause shock damage to individuals using
communication apparatus like telephones. Andrews et al., [14] describes the mechanisms of
personal danger from telephone apparatus.
Internal mechanical damage within residential buildings threatens individuals within an
otherwise safe dwelling.
Electric current causing muscle contraction may also propel a victim into an object, or induce a
fall.
Overhead cables entering a building can also carry dangerous currents to the interior. Some
amelioration of this danger can be provided by earth shielding wires.
These are a few examples of primary and secondary injury which can affect humans and
livestock.
Additional information of primary and secondary injury are given in the documents from Rakov
[50], [51].
4.5 Summary
There are multiple paths of entry and impingement for lightning current onto an individual via
power and communication cabling.
This risk is an addition to the ways in which lightning impulses can impinge on an individual
"directly", that is, without the external agencies enumerated in examples above.
5 Interaction of strokes with human beings and livestock
5.1 General
The possible interaction of lightning current directly with living beings can take one of five forms
[30], and effects depend on the pathway of the current in the body and on its surface. As the
temporal and spatial current distribution of strokes varies, so the effects on living organisms
are different. The five types of interaction are described below.
The body is essentially capacitive in nature. When a lightning impulse attaches to a body,
current is conducted internally to the body. The body’s capacitances charge and the electric
field over the surface of the body reaches a value where breakdown occurs. The value depends
on the nature of the surface, the nature of skin, the nature of surface hair, the state of wetness
and so on. While metal worn on the body has no effect on attracting a lightning impulse, it may
affect the flashover path and breakdown phenomenon.

– 14 – IEC TR 60479-4:2020 © IEC 2020
Once flashover occurs, internal current decreases quickly, and the majority of current is
transmitted in the external flashover.
Nonetheless the flashover duration is still very small in absolute terms, and the internal
conduction time is even smaller, perhaps accounting for the fact that burns in lightning injury
are a very small feature.
It has been noted that body orifices, such as eyes, ears, mouth, and nose, provide re-entry
portals for current, and the path from these to sensitive parts of the brain (e.g. eyes, otic
apparatus, temporal lobes, respiratory centres, brainstem) is short and direct. Coupled with the
ready conducting ability of the cerebrospinal fluid (CSF), the possibility for damage to central
nervous system structures is high.
5.2 Strike mechanisms
5.2.1 Description of direct strike
When the tip of the downward stepped leader has reached a height of some tens of metres
above ground level, the resulting field strength attains a critical value so that an upward
streamer, influenced by the downward stepped leader, can be initiated from prominent items
such as structures, trees, or possibly victims. When one of the upward streamers connects with
the stepped leader, a lightning channel is formed [6], [30] making an attachment directly with
the stricken object which may be a living being (see Figure 3). A return stroke then flows via
the channel.
Figure 3 – Direct strike
The current flowing in this circumstance has been estimated.
There is no data on exact currents, partly because of difficulty in obtaining research subjects.
A further reason is that the lightning attachment process is so variable that consistent
repeatable measurements are not possible. Thus the data following is intended to provide
representative values only.
A 5 kA 8/20 µs stroke is illustrative. This is a small stroke.
The sequence of events is shown in Figure 4. An artificial situation with no flashover establishes
that foot flashover and body flashover occur well before the 1 µs.

The flash is postulated to attach to the cranium of a person 2 m tall. Using representative
capacitance, the field over the body reaches 4 000 V/cm at approximately 550 ns from
attachment. Flashover occurs over the surface at this value, by which time the internal current
has risen to approximately 1 280 A. At that point the internal current drops dramatically, and in
the 8 µs that the applied current continues to build, it is conducted externally.

Figure 4 – Direct strike with no flashover and then with flashover
The internal charge transfer is therefore approximately 1 mC.
5.2.2 Description of contact voltage
When an object, not necessarily metallic, is struck by lightning, points on its surface are raised
in potential. When a living being contacts one of these points and another, possibly earth, to
complete a circuit, lightning current will flow through the victim [6], [30]. This contact voltage is
determined by a resistive and an inductive component [1] (Figure 5).

Figure 5 – Contact potential
The voltage at the contact point is given by:
u = i R + Ldi /dt
L L
where
u is the resulting contact voltage, i is the current through a vertical structure, and R and L are

L
the resistance and inductance between the points of contact.
The consequences for internal and external current conduction are similar to that for direct flash.

– 16 – IEC TR 60479-4:2020 © IEC 2020
5.2.3 Description of side flash
When a person is near, but not touching, a vertical structure which conducts lightning current,
potential is distributed over the object in the same way as with contact voltage. The resulting
potential difference may exceed the electrical breakdown strength of the gap between the object
and a person standing nearby. Then a side flash occurs [6], [30] (Figure 6) from the object to
the victim. Figure 8b) shows the case where the vertical structure is another human being.

Figure 6 – Side flash
5.2.4 Description of step voltage
The common means by which a step voltage is generated occurs when a lightning impulse is
injected into the earth [6], [30]. Passing through the earth resistance, a potential gradient is set
up. Two points of contact of a victim establishes a potential difference between those points,
and current flows through the victim.
The potential is given by

ρI 11
U −

step
2π r r
12
where the step voltage is U and I is the current injected into ground of resistivity ρ, and r
step 1
are the distances from the base of the strike of the two contact points.
and r
Suppose a lightning stroke of 10.000 A is injected into the ground of resistivity of 100 Ωm, with
two points at 20 m and 21 m distant. The step voltage is then approximately 378 V.
For these values, the voltage profile is shown in Figure 7:
=
Figure 7 – Earth potential versus distance from the stroke base –
10 kA stroke, with earth resistivity 100 Ωm
This voltage between two human feet is unlikely to be harmful.
However, in a quadruped, with 2 to 3 times the step distance, the step voltage becomes
approximately 1 000 V. The pathway of the currents in quadrupeds may include the heart
(Figure 8c)). Another reason that quadrupeds are much more likely to be killed is that they often
stand in muddy ground so that their legs are in particularly good contact with the ground.
Often, if the pathway of step voltages for humans does not include the heart, for example if the
victim is standing vertically with feet in contact with the ground, the victim is often temporarily
paralysed in the extremity involved in the current passage (keraunoparalysis). Keraunoparalysis
can occur with any lightning conduction involving an extremity.
5.2.4 Description of streamer current
If an upward streamer emanates from a living being, the associated charge will travel current
through the victim from earth. It emanates in answer to the descending stepped leader, and
may be said to be induced by the stepped leader. The current that flows in this way may produce
injuries in the victim (Figure 9) [2], [3], [25], [26].

– 18 – IEC TR 60479-4:2020 © IEC 2020

a) For a human being: current travels out radially from the base of the strike (β). The current travelling through the
earth resistance sets up isopotentials (α) of decreasing magnitude from the base of the strike. For the human,
foot "a" is at a higher potential than foot "b", and current flows internally in the body from foot to foot.
b) For two humans: combined with side flash.
c) For a quadruped: noting the vulnerability of the chest, and therefore heart.
Figure 8 – Examples of step voltages, assuming a uniform earth
of constant resistivity, and no surface flashover

Figure 9 – Upward streamer
Becerra and Cooray [16] examine the currents flowing. They are shown in Figure 10 a) and
Figure 10 b).
a) Current in establishment of upward streamer b) Current in collapse of upward streamer
SOURCE: Becerra and Cooray [16], reproduced with permission from the authors.
Figure 10 – Current in establishment and in collapse of upward streamer
Two phases of current passage are identified. The first is during the phase of establishment of
the upward streamer. The second is during the collapse of the streamer. Figure 10 a) and
Figure 10 b) show these phases. The time constants applicable are a complex interplay of earth
resistance, individual resistance, and individual capacitance, and environmental capacitance.
5.3 Specific matters regarding body response
Attachments close to the head of victims initiate current which has been found to enter the body
at cranial orifices as portals of entry, including the ear canals, the eye apparatus, the mouth
and the nose. These portals provide easy access to body fluids, especially blood and CSF.
Conduction paths to the brainstem and the heart are plain, and thus cardiac and respiratory
dysfunction is likely, and has been demonstrated.

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Investigation shows that the heart enters asystole, and then re-establishes its own automatic
rhythm. Respiratory cessation is seen, and no automatic rhythm re-establishes, leading to a
secondary hypoxic cardiac arrest [7].
The establishment of asystole rather than ventricular fibrillation (VF) may be a function of the
size of the cardiac insult. The establishment of VF often occurs due to an isolated focus of
ventricular depolarization with irregularities in ventricular conduction. Various theories of VF
exist including a) the consequent establishment of circus rhythms on the one hand, or
alternatively b) the multiple wavelet theory resulting from multiple areas of stimulation.
With lightning injury however, the stimulus is almost certainly above the upper limit of
vulnerability (ULV) for defibrillation, and thus induces complete myocardial depolarization
without the VF possibilities above. Asystole is the result.
There is no evidence to support the once stated contention that body metabolism ceases after
a lightning strike, and time available for external resuscitation is prolonged [55]. It is a prime
principle of first aid for lightning victims (vide infra) that cardiopulmonary resuscitation (CPR)
should be commenced early and kept up for a prolonged period, as various neural signs of
decease may be unreliable.
Current paths through the body are thought to follow most easily the paths of low resistance i.e.
fluids like blood and CSF. However there are multiple parallel paths through which current will
flow, in proportion to their conductivity [54]. No tissue may be considered exempt from the
passage of current and its effects, and current passage will be through all pathways in inverse
proportion to their resistances.
6 Effects of lightning strokes on the body of living beings
6.1 General comments on effects on the body
A tabulation of the majority of injuries is given below. General comments are made first.
If electric current flows through the body of living beings, damage and/or malfunction can occur.
Lightning current is an example of such injuring current. Unlike technical electric shock, a
lightning impulse generally injects current into the body, whereas an applied technical voltage
causes current to flow through body impedance. The exception is exposure to step potential.
Direct strike obviously gives rise to the greatest harm, and probably the most mortality, whereas
step potential is possibly the le
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