2007, Piran, Slovenia

Cognitive and Psycophysiological Function
THE REPRODUCIBILITY AND VALIDITY OF VISUAL
ANALOGUE SCALES (VAS) THAT ASSESS THERMAL
PERCEPTIONS IN STABLE AND DYNAMIC, ASYMMETRIC
ENVIRONMENTS
Sarah Davey, Tara Reilly, Mark Newton and Michael Tipton
Department of Sport & Exercise Science, Institute of Biomedical & Biomolecular
Sciences, University of Portsmouth, UK.
Contact person: sarah.davey@port.ac.uk
INTRODUCTION
Historically, 4-7 point Likert or categorical scales have been used to assess the
perceptions of humans of their thermal state (Fanger, 1970). The validity of these
scales in stable uniform environments has been well established (ASHRAE, 1997),
however their application in dynamic, asymmetric environments producing small
changes in human thermal perceptions is less well understood and may be
compromised; for example, when assessing the impact of regional heating or cooling
on overall thermal perception (Zhang, 2003). In such situations, visual analogue
scales (VAS) could provide a more sensitive tool by enabling finer adjustments.
However, a possible drawback of being more sensitive is a reduction in
reproducibility.
The aim of this investigation was to evaluate the reproducibility and validity of visual
analogue scales to assess local and overall thermal comfort (TC) and temperature
sensation (TS) in stable and dynamic, asymmetric environments.
METHODS
Following ethical approval, nine heat acclimated males aged (mean ±SE) 20.4 ± 2.2
y., mass 73.18 ± 7.8kg, Body fat (%) 13.15 ± 5.1, VO2max 64.48 ± 7.1 mL. kg -1 .min -1
completed three identical trials where their perceptual measurements of TS, torso
temperature sensation (TTS), TC and torso thermal comfort (TTC) were assessed
every five minutes whilst walking on a treadmill (4.5-5km.h -1 , 2% incline) in an hot
environment (35 o C, 50% RH) for 130 mins.
To assess local and overall thermal perceptions in static and dynamic thermal
conditions, the subjects wore an air cooled garment (ACG) over the torso, this enabled
the temperature and humidity of the air entering the microclimate to be manipulated.
Each subject followed one of two microclimate profiles (Figure 1), each consisting of
two phases, stable (0-60mins) and dynamic (60-130mins).
Thermal Perceptual Scales
The VAS were adapted from scales previously developed to investigate local and
overall TS and TC in dynamic, asymmetric environments (Zhang, 2003). To validate
the VAS, measurements were taken alongside previously validated Likert scales (LS)
(ASHRAE, 1997). Physiological measurements included rectal temperature (T core),
mean torso temperature (chest and shoulder) (T skintorso) and body temperature (T body
= 0.8 T core + 0.2 T skintorso). Both scales were displayed on a touch screen monitor, a
stylus pen was used to enter data.
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