2007, Piran, Slovenia

Thermal Sensation Scale
10
9
8
7
6
5
4
3
2
Acute and chronic heat exposure
1
0 10 20 30 40 50 60 70
Time (min)
True Cooling
Sham Cooling
No Cooling
Figure 2. Perceptions of thermal sensation over 60 min with cooling hood (dashed vertical line)
plus 10 min additional passive rest without hood. No significant decreases in either True
Cooling and Sham Cooling conditions over time or compared to No Cooling condition.
DISCUSSION
We investigated the use of head and neck cooling as a manipulation to uncouple conscious
perception of thermal manipulation from actual physiological cooling. As with a previous
study on individuals with MS, head and neck cooling was able to significantly decrease rectal
temperature. Cooling in our protocol of 60 min exceeded the 0.2 o C drop after 30 min reported
by Ku et al. (1999) using a similar head cooling device, demonstrating a progressive decrease
with continued cooling. Furthermore, the 0.37 o C drop in rectal temperature 10 min following
the 60 min cooling is near the typical range of 0.4-0.7 o C reported in pre-cooling studies
utilizing whole-body cooling. This suggests that head and neck cooling alone may be an
effective and portable pre-cooling manipulation without the requirement of water baths,
showers, or whole-body cooling suits with their larger power and coolant requirements.
The unique aspect of the present study was the incorporation of a sham cooling manipulation,
with the intention of providing the perception of cooling without altering temperature. While
successful in the latter objective, no changes were reported in thermal sensation throughout
any of the three thermal conditions, with verbal equivalents of “Slightly Cool” to “Cool” in
the majority of subjects in response to both the True Cooling and Sham Cooling conditions.
However, qualitative feedback from subjects, who were blinded to both the conditions and the
purpose of the study, was that they could not distinguish between the True and Sham Cooling
conditions, and that they felt cool in both conditions.
One important limitation of the present study was that, like Ku et al. (1999), the subject
population was from individuals with MS. Multiple Sclerosis is an immune-mediated disorder
that targets the central nervous system (CNS), resulting in demyelination of axons, and it is
possible that the observed thermal and perceptual responses may be specific to this
population. Therefore, data collection is ongoing to extend this work to healthy individuals
without clinical symptoms.
REFERENCES
Ku, Y., Montgomery, L.D., Wenzel, K.C., Webbon, B.W. and Burks, J.S., 1999. Physiologic
and thermal responses of male and female patients with multiple sclerosis to head and
neck cooling. Am. J. Phys. Med. Rehabil. 78, 447-456.
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