Activity: Pain Perception During Ice Immersion
Objective:
The student will gain an understanding of the four sensations commonly related to
cold application, acquire knowledge in the use of pain scales.
Materials Needed:
 Ice immersion bucket
 Numerical rating scale
 Timing device
 Thermometer for measuring temperature of the immersion
Description of the Numerical Rating Scale:
The Numerical Rating Scale (NRS) uses a numerical scale ranging from “0,” representing “no
pain” to “10,” representing the “worst pain imaginable.” Subjects are then asked to circle the
whole number between 0 and 10 that best represents their current pain level. The advantage
of this system lies in the use of graded intervals to measure pain intensity. The disadvantage
is in the lack of descriptors at the extremes.
Procedures for Using the Numerical Rating Scale
Subjects view the NRS and circle the number best describing their current level of pain. It is
customary to circle only a whole number. Therefore circling “7” is an appropriate response
whereas marking the position on the grid representing “7.5” is not appropriate. When multiple
measures are being made, the subject is not permitted to view the previous response. We
recommend that once a scale is marked, it be covered with a piece of paper until the exercise
is completed.
Procedures:
1. Fill an immersion bucket with water and add enough ice to decrease the temperature
between 50° and 55° F.
2. Inform the subject that this activity will cause a moderate amount of pain. If the pain
becomes too great or if the subject experiences lightheadedness, discontinue the
activity.
3. Instruct the subject to immerse a leg in the bucket.
4. After 1 minute have the subject circle the number on the modified NRS that best
describes the level of pain experienced.
5. Cover this and future responses so that the subject cannot see the previous responses.
6. Repeat the pain scale every minute for the duration of the treatment.
7. Plot the changes in perception of cold sensation over time on the accompanying
worksheet.
8. Repeat this activity with the other partner using the same leg.
Discussion:
The degree of vulnerability of different nerves to cold application accounts for the changes in
sensation experienced as the cold treatment progresses. Unmyelinated, small-diameter,
superficial pain nerves are stimulated before the larger, myelinated, and deeper lying nerves.
As the exposure to the cold continues, the perception of pain decreases because of the
decrease in nerve conduction velocity of these nerves and the subsequent stimulation of
sensory nerves.
It is commonly reported that four distinct sensory phases will be experienced during cold
application: cold, burning, aching, and analgesia. However, true analgesia (the inability to
transmit nerve impulses) has not been proven to occur during ice immersion.
Pre-Activity Questions:
1. Describe in your own words why we would use a pain scale to establish a person’s pain
level.
2. What do think will happen when you’re foot is immersed in an ice bath (What will the
pain be like)?
Ice Immersion Pain Perception Data
1 Minute
Post-Immersion
2 Minute
Post-Immersion
Subjects Name:
3 Minute
Post-Immersion
4 Minute
Post-Immersion
5 Minute
Post-Immersion
6 Minute
Post-Immersion
7 Minute
Post-Immersion
8 Minute
Post-Immersion
9 Minute
Post-Immersion
10 Minute
Post-Immersion
Plot of Pain Perception Over Time
Worst Pain Imaginable
10
9
8
7
6
5
4
3
2
1
No Pain
0
1
2
3
4
5
6
7
8
10
9
Minutes
Activity Questions:
3. Did your foot and ankle become numb during the emersion? YES or NO
Explain why this is.
4. Where was your pain located primarily?
5. Was there anyone in the class who was a first-time cold user? YES or
If YES, how did there pain compare with that of everyone else?
NO