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2 Review of Literature: Motorcycle helmet
interests of the cyclist in mind. Research needs to be undertaken that facilitates an
informed holistic approach to the design of bicycle helmets.
In countries where helmet usage is mandatory, the thermal discomfort caused by
wearing a helmet while cycling creates a barrier to helmet wearing [29]. The first
published paper relating to the physiological effects of wearing a bicycle helmet was
done by Gisolfi et al. [30]. Many researchers have investigated and measured the
thermoregulatory responses experienced by the cyclist while cycling with or without
a helmet [31–33].
Stern [31] found that there is a high statistical difference between scalp temperatures when cycling with and without a helmet. Maximum scalp temperature was
found to be 36.13 °C without a helmet as compared to 37.58 °C with a helmet. Gisolfi
et al. [30] observed that wearing a helmet produces a perceived thermal discomfort
in the cyclist. Heat loss in bicycle helmets was found to have very large variations
in the presence of forced convection [34, 35]. However, this is in part due to the fact
that sweating and discomfort make the cyclist more sensitive (per unit surface area)
to changes in the temperature of the head (especially the face) than to changes in the
temperature of other skin regions [36, 37].
2.8 The Effects of Discomfort in Helmets
Slater [38] defined comfort as ‘a pleasant state of physiological, psychological and
physical harmony between a human being and the environment’. He also defined
these three aspects of comfort and discussed the role of environment in comfort. All
three aspects are equally important for comfort, and if any one of them is missing,
the person will feel discomfort. Comfort is the perception of the human mind caused
by the integration of impulses in the brain passed up by the nerves from peripheral
receptors. This perception is mainly affected by the clothing between the human body
and the environment. Comfort can also be defined as ‘freedom from pain and from
discomfort as a neutral state’ [39]. Büttner [40] recognised that, for the assessment of
the thermal influence of the environment on the human body, the integrated effects
of all thermal parameters have to be taken into account. In this regard, empirical
thermal indices, such as the discomfort index [41], apparent temperature [42], wind
chill index [43] or similar ones considering some of the relevant meteorological
parameters but not accounting for thermal physiology, have to be regarded as not
being state of the art, yet they are used very often. Despite many limitations, these
parameters are useful in very specific situations as they can be calculated easily.
To be effective in tropical countries, helmets must be comfortable, affordable
and provide protection in various traffic conditions. In addition, high humidity and
temperature in tropical countries cause the temperature inside the helmet to rise
to uncomfortable levels. This rise in temperature affects the concentration of the
motorcyclist [44, 45]. Hence, it is necessary to find ways to reduce the temperature
inside the helmet and thus minimise the heat stress of the motorcyclist.
2 Review of Literature: Motorcycle helmet
interests of the cyclist in mind. Research needs to be undertaken that facilitates an
informed holistic approach to the design of bicycle helmets.
In countries where helmet usage is mandatory, the thermal discomfort caused by
wearing a helmet while cycling creates a barrier to helmet wearing [29]. The first
published paper relating to the physiological effects of wearing a bicycle helmet was
done by Gisolfi et al. [30]. Many researchers have investigated and measured the
thermoregulatory responses experienced by the cyclist while cycling with or without
a helmet [31–33].
Stern [31] found that there is a high statistical difference between scalp temperatures when cycling with and without a helmet. Maximum scalp temperature was
found to be 36.13 °C without a helmet as compared to 37.58 °C with a helmet. Gisolfi
et al. [30] observed that wearing a helmet produces a perceived thermal discomfort
in the cyclist. Heat loss in bicycle helmets was found to have very large variations
in the presence of forced convection [34, 35]. However, this is in part due to the fact
that sweating and discomfort make the cyclist more sensitive (per unit surface area)
to changes in the temperature of the head (especially the face) than to changes in the
temperature of other skin regions [36, 37].
2.8 The Effects of Discomfort in Helmets
Slater [38] defined comfort as ‘a pleasant state of physiological, psychological and
physical harmony between a human being and the environment’. He also defined
these three aspects of comfort and discussed the role of environment in comfort. All
three aspects are equally important for comfort, and if any one of them is missing,
the person will feel discomfort. Comfort is the perception of the human mind caused
by the integration of impulses in the brain passed up by the nerves from peripheral
receptors. This perception is mainly affected by the clothing between the human body
and the environment. Comfort can also be defined as ‘freedom from pain and from
discomfort as a neutral state’ [39]. Büttner [40] recognised that, for the assessment of
the thermal influence of the environment on the human body, the integrated effects
of all thermal parameters have to be taken into account. In this regard, empirical
thermal indices, such as the discomfort index [41], apparent temperature [42], wind
chill index [43] or similar ones considering some of the relevant meteorological
parameters but not accounting for thermal physiology, have to be regarded as not
being state of the art, yet they are used very often. Despite many limitations, these
parameters are useful in very specific situations as they can be calculated easily.
To be effective in tropical countries, helmets must be comfortable, affordable
and provide protection in various traffic conditions. In addition, high humidity and
temperature in tropical countries cause the temperature inside the helmet to rise
to uncomfortable levels. This rise in temperature affects the concentration of the
motorcyclist [44, 45]. Hence, it is necessary to find ways to reduce the temperature
inside the helmet and thus minimise the heat stress of the motorcyclist.