Does bad sleep and mood make pain feel worse?
Interrupted sleep slightly increases how intensely people feel pain, but induced positive or negative moods do not change this effect.
Source
Effects of Sleep Fragmentation and Induced Mood on Pain Tolerance and Pain Sensitivity in Young Healthy Adults
What they did
The researchers tested a group of 35 healthy young adults. Participants underwent a session of undisturbed sleep and another session where their sleep was interrupted by phone calls every 80 minutes, forcing them to remain awake for at least 10 minutes during each awakening. The morning after, researchers induced positive or negative emotions using videos and facial posturing, then measured the participants' responses to painful pressure and cold water.
What they found
Interrupting sleep led to a small but statistically significant increase in how intensely participants felt cold pain, though it did not change how long they could tolerate the cold. Additionally, the experimental changes in mood did not alter pain ratings or influence the connection between sleep loss and pain sensitivity.
The limits
What it doesn't show
The study was limited by its small sample of 35 healthy young adults, which makes it difficult to apply these findings directly to clinical populations suffering from long-term chronic pain. Because the researchers disrupted sleep for only one night, the study does not capture the cumulative, long-term effects of sleep loss that build up over weeks. Furthermore, repeating the pain tests multiple times might have allowed participants to develop coping mechanisms, potentially masking the full impact of sleep loss on pain threshold.
Key terms
- Sleep fragmentation
- A sleep disturbance characterized by repeated, short awakenings throughout the night, disrupting the continuity of sleep without necessarily reducing total sleep time dramatically.
- Conditioned pain modulation (CPM)
- An experimental paradigm where a secondary painful stimulus is used to inhibit the perceived pain of an initial test stimulus, serving as a measure of the body's internal pain-control mechanisms.
- Cold pressor test (CPT)
- A laboratory procedure used to evaluate pain tolerance and intensity by having participants submerge their hand and wrist in freezing water.
- Pressure pain threshold (PPT)
- The minimum amount of physical force or pressure applied to a body part that is perceived by a participant as being painful.
- Facial feedback theory
- The hypothesis that skeletal muscle activity in the face, such as smiling or frowning, can directly influence and trigger corresponding emotional experiences.
Flashcards
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Quiz yourself
Why is sleep fragmentation experimentally preferred over total sleep deprivation when studying pain in chronic conditions?
Common questions
How did the researchers make sure the participants actually woke up during the night?
The researchers called the participants on the phone periodically during the night and required them to fill out online questionnaires that took at least 10 minutes to complete, verifying their active wakefulness.
Why did the researchers focus on sleep fragmentation instead of total sleep deprivation?
Sleep fragmentation, where sleep is frequently interrupted, more closely mimics the real-world sleep difficulties experienced by chronic pain patients compared to completely staying awake all night.
Did positive or negative emotions help reduce or increase pain?
Surprisingly, the study found no evidence that induced positive or negative moods changed how participants perceived pain or how sleep loss affected pain.
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