The Impact of Insomnia on Pain Sensitivity and the Trajectory of Exercise-induced Muscular Pain

The Impact of Insomnia on Pain Sensitivity and the Trajectory of Exercise Induced Muscular Pain: a Case Control Study

Sleep is a critical determinant of physiological recovery and pain regulation. Growing evidence suggests that sleep disruption directly heightens central and peripheral pain sensitivity to sensory stimuli (e.g., mechanical pressure, thermal stimuli), serving as a significant risk factor for the onset and persistence of musculoskeletal pain. However, the precise mechanisms through which sleep quality regulates bodily sensory sensitivity and influences the onset, progression, and recovery trajectories of acute musculoskeletal pain in the general public remain insufficiently understood.

This study aims to investigate the relationship between sleep condition, pain sensitivity, and musculoskeletal pain dynamics in healthy adults from the general population, regardless of their physical activity levels. Utilizing a standardized, safe, and fully reversible exercise-induced muscle soreness (EIMS) protocol as an experimental pain model, this project will continuously evaluate participants' quantitative sensory testing (QST) profiles and sleep parameters.

The findings from this study will advance the mechanistic understanding of sleep-mediated pain modulation, providing evidence-based insights to inform future targeted sleep management and pain prevention interventions.

Study Overview

• Status: Recruiting
• Conditions: Musculoskeletal Pain; Insomnia; Healthy Adult; Pain Sensitivity
• Intervention / Treatment: Other: Eccentric exercise

• Study Type: Observational
• Enrollment (Estimated): 80

Contacts and Locations

• Study Contact: Name: Leo Guohui Lin; Phone Number: +852 94267004; Email: guohui-leo.lin@connect.polyu.hk

Study Locations

• Hong Kong
  • Hong Kong, Hong Kong
    • Recruiting
    • The Hong Kong Polytechnic University
    • Contact: Leo Guohui Lin; Phone Number: +852 94267004; Email: guohui-leo.lin@connect.polyu.hk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Healthy Adult with or without insomnia

Description

Inclusion Criteria:

• Adults aged 18 to 60 years
• Right hand and foot dominant

Exclusion Criteria:

• History of any chronic musculoskeletal pain or presence of existing pain during recruitment
• Previous major injuries or surgery involving the lower limbs
• Sleep disorders other than insomnia
• Clinically diagnosed psychiatric disorders
• Contraindications to vigorous exercise identified through the physical activity readiness questionnaire (PAR-Q)
• Work night shifts or rotating shift schedules
• Pregnant

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Insomnia	Other: Eccentric exercise; Eccentric hamstring exercise
Healthy contry	Other: Eccentric exercise; Eccentric hamstring exercise

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Muscle damage severity: Muscle pain	Muscle pain will be measured by an 11-point NRS, with 0 represents "no pain" and 10 indicating "worst imaginable pain". The Outcome will be recorded at rest, reach for the floor with knees straight, and during a validated hamstring provocative manoeuvre, the "taking-off shoe" test.	Day 0 to Day 14
Muscle damage severity: Muscle soreness	Muscle soreness will be measured by an 7-point Likert scale, with 0= A complete absence of soreness," 1 = "A light soreness in the muscle felt only when touched/a vague ache," 2 = "A moderate soreness felt only when touched/a slight persistent pain," 3 = "A light muscle soreness when walking up and down stairs," 4 = "A light muscle soreness when walking on flat surface," 5 = "A moderate muscle soreness, stiffness, or weakness when walking," 6 = "A severe muscle soreness, stiffness, or weakness that limits my ability to move."	Day 0 to Day 14
Pain Sensitivity: Thermal pain threshold	Thermal thresholds will be measured with a 30 × 30 mm thermode (TSA 2, Medoc Ltd., Ramat Yishai, Israel). The thermode will be placed gently on the skin without causing deformation. Using the method of limits, temperature will increase or decrease at 1℃/second within a 0 - 51℃ range, with a baseline temperature of 32℃. Participants will press the stop button when the thermal sensation first becomes painful. The mean value of five consecutive trials will be used in the analysis.	Day 7 and Day 9
Pain Sensitivity: Mechanical pain threshold	Mechanical pain threshold will be evaluated using standardised weighted pinprick stimulators (MRC System GmbH, Heidelberg, Germany) with a 0.25mm flat contact area. Seven fixed intensities (8 mN - 512 mN) will be applied. The final threshold will be calculated as the geometric mean of the ascending and descending stimulus intensities from five series.	Day 7 and Day 9
Pain Sensitivity: Pressure pain threshold	Pressure pain threshold will be assessed with a digital pressure algometer (Medoc Ltd., Ramat Yishai, Israel) equipped with a 1 cm2 rubber probe. Pressure will be applied at 30 Kpa per second until participants perceive painful. Three trials will be performed, and the mean scores will be calculated to determine the PPT.	Day 7 and Day 9
Pain Sensitivity: Temporal summation of mechanical pain (TSP-M)	The pinprick stimulator will assess TSP-M at 256 mN. Ten stimuli will be delivered at 1-second intervals over a 1 cm2 area. Pain intensity will be rated on an 11-point NRS after the first and the 10th stimuli. If the NRS pain rating remains 0 out of 10 for three consecutive 256 mN stimuli, intensity will be increased to 512 mN, and the trial will be repeated. TSP-M will be calculated as the NRS difference between the first stimulus and the 10th stimulus.	Day 7 and Day 9
Pain Sensitivity: Temporal summation of heat pain (TSP-H)	TSP-H will be measured with a 9 cm2 thermode (TSA 2, Medoc Ltd., Ramat Yishai, Israel). Two sequences of 10 heat pulses at 46 ℃ and 48 ℃ will be delivered with a 5-minute interval. Each pulse has a 0.5 s duration and will be delivered from a 40 ˚C baseline at a 13°C/s ramp rate and 2.5 s interstimulus interval. The participant will rate pain intensity on an 11-point NRS after each stimulus. TSP-H will be defined as the NRS difference between the 10th stimulus and the first stimulus for each temperature.	Day 7 and Day 9
Pain Sensitivity: Conditioned pain modulation (CPM)	CPM will be evaluated using a noxious conditioning stimulus (CS) and a test stimulus (TS). The CS will be contact heat applied to the dominant volar forearm between the distal third of the forearm and the ulnar styloid. Temperature will be set 1.1 °C above the participant's HPT for 120s, starting from 32 ℃ with an 8°C/s ramp using the TSA 2 device (Medoc Ltd., Ramat Yishai, Israel). During the CPM assessment, if participants could not tolerate the CS (i.e., pain intensity over 8 on the11-point NPRS) or if they reported a pain intensity below 4 on the 11-point NPRS, the temperature of the CS will be adjusted to ensure a safe and adequate stimulus intensity. The TS will be applied to the thenar eminence of the non-dominant hand using a pressure algometer (Medoc Ltd., Ramat Yishai, Israel) to determine PPT before and immediately after the CS. The CPM effect will be calculated by subtracting the PPT measured before the CS from the PPT measured after the CS.	Day 7 and Day 9

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sleep diary: Sleep Onset Latency (SOL)	Assessed using a daily consensus sleep diary. Sleep Onset Latency is the estimated time (in minutes) it takes to fall asleep after turning off the lights. Lower values indicate better sleep onset.	Day 0 to Day 14
Sleep diary: Wake After Sleep Onset (WASO)	Assessed using a daily consensus sleep diary. WASO is calculated as the total duration of wakefulness (in minutes) between initial sleep onset and final awakening, derived from the number of night awakenings multiplied by their average duration. Lower values indicate better sleep continuity.	Day 0 to Day 14
Sleep diary: Sleep Efficiency (SE)	Assessed using a daily consensus sleep diary. Sleep Efficiency is calculated as the percentage of time in bed spent asleep: [(Total Sleep Time / Total Time in Bed) × 100]. Total Sleep Time is derived from total time in bed (time between bedtime and rise time) minus sleep onset latency and nocturnal wakefulness (calculated from the number and duration of night awakenings). Scores range from 0% to 100%, with higher percentages indicating better sleep quality.	Day 0 to Day 14
Actigraphy: Total Sleep Time (TST)	Measured objectively using a wrist-worn ActiGraph accelerometer and validated sleep-scoring algorithms. Total Sleep Time is defined as the total amount of time spent sleeping between bedtime and rise time. Higher values indicate longer sleep duration.	Day 0 to Day 14
Actigraphy: Wake After Sleep Onset (WASO)	Measured objectively using a wrist-worn ActiGraph accelerometer. WASO is defined as the total number of minutes spent awake after initial sleep onset and before final awakening, as determined by epoch-by-epoch movement counts. Lower values indicate better sleep continuity and fewer night awakenings.	Day 0 to Day 14
Actigraphy: Sleep Efficiency (SE)	Measured objectively using a wrist-worn ActiGraph accelerometer. Sleep Efficiency is calculated as the percentage of time in bed spent asleep: [(Total Sleep Time / Total Time in Bed) × 100]. Values range from 0% to 100%, with higher percentages indicating better sleep quality and efficiency.	Day 0 to Day 14
Sleep Questionnaires: the Insomnia Severity Index (ISI)	The ISI is a 7-item self-report questionnaire assessing the nature, severity, and impact of insomnia. Each item is rated on a 5-point Likert scale (0 to 4). The total score ranges from 0 to 28, with higher scores indicating greater severity of insomnia	Day 0 and Day 7
Sleep Questionnaires: The Pittsburgh Sleep Quality Index (PSQI)	The PSQI is a 19-item self-report questionnaire that evaluates sleep quality and disturbances over a 1-month time interval. It generates seven component scores: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleep medication, and daytime dysfunction. Each component is scored from 0 to 3. The sum of these seven component scores yields a global PSQI score ranging from 0 to 21, where higher scores indicate poorer sleep quality.	Day 0 and Day 7
Psychological measurement: Depression, Anxiety, and Stress Scale (DASS-21)	Assessed using the 21-item Depression Anxiety Stress Scales (DASS-21). The instrument consists of three 7-item subscales measuring depression, anxiety, and stress. Each item is rated on a 4-point Likert scale ranging from 0 ("did not apply to me at all") to 3 ("applied to me very much or most of the time"). Sum scores for each subscale are calculated and multiplied by 2 to yield total scores ranging from 0 to 42 for each dimension (Depression: 0-42, Anxiety: 0-42, Stress: 0-42), with a total overall score ranging from 0 to 126. Higher scores indicate greater levels of psychological distress/severity.	Day 0, Day 7, and Day 9
Psychological measurement: Pain Catastrophizing Scale (PCS)	Assessed using the 13-item Pain Catastrophizing Scale (PCS) to evaluate catastrophic thoughts and feelings associated with pain (comprising rumination, magnification, and helplessness subscales). Each item is rated on a 5-point Likert scale from 0 ("not at all") to 4 ("all the time"). The total score ranges from 0 to 52, with higher scores indicating higher levels of pain catastrophizing.	Day 0, Day 7, and Day 9
Psychological measurement: Fear of Pain Questionnaire (FPQ-9)	Assessed using the 9-item short form of the Fear of Pain Questionnaire (FPQ-9) to assess fear of different painful experiences across severe pain, minor pain, and medical pain domains. Each item is rated on a 5-point Likert scale from 1 ("not at all") to 5 ("extreme"). The total score ranges from 9 to 45, with higher scores indicating greater fear of pain.	Day 0, Day 7, and Day 9
Psychological measurement: Tampa Scale for Kinesiophobia (TSK-11)	Assessed using the 11-item Tampa Scale for Kinesiophobia (TSK-11) to evaluate fear of movement or (re)injury. Each item is scored on a 4-point Likert scale ranging from 1 ("strongly disagree") to 4 ("strongly agree"). The total score ranges from 11 to 44, with higher scores indicating greater fear of movement/kinesiophobia.	Day 0, Day 7, and Day 9
Sleep diary: Total Sleep Time	Assessed using a daily consensus sleep diary. Total Sleep Time is calculated as the total time spent asleep, derived from the total time in bed (bedtime to rise time) minus sleep onset latency and wake after sleep onset. Higher values indicate longer sleep duration.	Day 0 to Day 14
Actigraphy: Sleep Onset Latency (SOL)	Measured objectively using a wrist-worn ActiGraph accelerometer. Sleep Onset Latency is defined as the period of time (in minutes) between the initial bedtime (lights out) and the onset of continuous sleep detected by the algorithm. Lower values indicate faster sleep onset and better sleep initiation.	Day 0 to Day 14
Physical Activity Level: International Physical Activity Questionnaire - Short Form (IPAQ-SF)	Assessed using the 7-item International Physical Activity Questionnaire - Short Form (IPAQ-SF). The questionnaire measures the duration (minutes) and frequency (days) of walking, moderate-intensity activities, and vigorous-intensity activities performed over the last 7 days. Total physical activity volume is calculated as MET-minutes per week (MET-min/week) using standardised MET energy expenditure values: Walking = 3.3 METs, Moderate PA = 4.0 METs, and Vigorous PA = 8.0 METs. Total score is the sum of (METs × minutes × days) across all three domains, with scores starting from 0 and no strict upper limit. Higher scores indicate higher levels of overall physical activity.	Day 0, Day 7, and Day 9

Collaborators and Investigators

• Sponsor: The Hong Kong Polytechnic University

Study record dates

Study Major Dates

• Study Start (Actual): August 26, 2026
• Primary Completion (Estimated): August 31, 2027
• Study Completion (Estimated): August 31, 2027

Study Registration Dates

• First Submitted: September 2, 2026
• First Submitted That Met QC Criteria: September 14, 2026
• First Posted (Actual): September 18, 2026

Study Record Updates

• Last Update Posted (Actual): September 18, 2026
• Last Update Submitted That Met QC Criteria: September 14, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Keywords: Healthy Volunteers; Insomnia; Sleep Quality; Eccentric exercise; Sleep Duration; Quantitative Sensory Testing (QST); Exercise-Induced Muscle Soreness; Recovery Trajectory
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Musculoskeletal Diseases; Nervous System Diseases; Muscular Diseases; Mental Disorders; Sleep Wake Disorders; Sleep Disorders, Intrinsic; Dyssomnias; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Musculoskeletal Pain; Sleep Initiation and Maintenance Disorders
• Other Study ID Numbers: Insomnia-DOMS-2026

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No