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NCT Number: NCT07101978

Hyperthermia in Patients With Chronic Primary Pain - Effects on Thermoregulation, Somatosensory System and Movement Evoked Pain

This study, in a quasi-experimental matched two-group pre-post design, investigates the effect of serial water-filtered whole-body hyperthermia on circadian core body temperature, the somatosensory system (nociception) and the movement evoked pain in healthy and patients with chronic primary pain (e.g., fibromyalgia). The intervention lasts 3 weeks with two treatment sessions per week.

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Key information

Conditions

Hyperthermia Body Temperature Changes Chronic Pain Chronic Primary Pain Circadian Rhythm Connective Tissue Diseases Fibromyalgia Healthy Heat Stress Disorders Muscular Disease Muscular Diseases Musculoskeletal Diseases Nervous System Diseases Neurologic Manifestations Neuromuscular Disease Neuromuscular Diseases Pain Pathological Conditions, Signs and Symptoms Quantitative Sensory Testing Rheumatic Diseases Signs and Symptoms Skin and Connective Tissue Diseases Somatosensory Function Widespread Pain Wounds and Injuries

Age range

18 year–70 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Bern University of Applied Science

Bern, Canton of Bern, 3012, Switzerland

Location contact

Kay-Uwe Hanusch, Dr.scient.med

CONTACT

[email protected]

+41 31 848 5005

About this study

A total of 30 healthy participants and 30 participants with chronic primary pain between the ages of 18 and 70 are being sought. All participants will receive the same amount of water-filtered whole-body hyperthermia in outpatient or semi-inpatient treatment. All abnormalities and side effects will be documented by the responsible therapists and doctors. Changes in circadian core body temperature, sensory or nociceptive sensitivities of the somatosensory system, and movement-evoked pain will be recorded, and blood parameters for nociceptive plasticity will be collected. For secondary efficacy, specific questionnaires on pain experience, fatigue, depression, and fear avoidance behavior will be collected 7 and 25 weeks after therapy.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

patients:

  • Confirmed diagnosis of widespread pain (ICD-11 MG30.01)
  • Widespread Pain Index (WPI) ≥ 7 and Symptom Severity (SS) scale ≥ 5 or WPI) ≥ 3 and SS ≥ 9,
  • Pain >= 3 month and VAS >= 4,0
  • Body - infrared-A-Bulb Distance < 38cm (overweight participants)
  • Signed declaration of consent

healthy:

  • No chronic illnesses
  • No acute infections
  • No regular medication: To avoid interactions
  • BMI ≤ 40kg/cm2
  • Mental health: No psychiatric diagnoses or psychotropic medication in your medical history

Exclusion criteria

  • Participation in other clinical studies
  • Contraindications for hyperthermia (severe cardiovascular diseases, tumour diseases, acute infections, pregnant and breastfeeding women)
  • Acute and / or feverish microbial infections
  • Participants with severe somatic, rheumatic concomitant endocrine or neurological diseases, in particular neurological diseases associated with cognitive disorders, severe liver or kidney and cardiac diseases
  • participants who are permanently treated with opioids, cannabis, immunosuppressive drugs (e.g. corticoids, immunosuppressants) or alpha/beta-A(nta)gonists due to a disease from the group described above
  • participants with pain due to a serious psychiatric illness (bipolar disorder, psychosis, personality disorder, severe depression, substance abuse) and serious systemic or neurological disorders
  • pregnancy or breastfeeding (for women)
  • Intake of medication within 6 weeks that inhibits the reuptake of the neurotransmitter serotonin or binds to receptors of this neurotransmitter group

Treatment and study plan

serial whole body hyperthermia

Behavioral

The hyperthermia treatment is carried out in a cycle of two treatments per week, with at least one day in between, over a period of three weeks, according to the manufacturer's instructions. According to the guidelines, the rectal (possibly vaginal) temperature (as body core temperature), heart rate and oxygen saturation (Sp02) are continuously determined during the hyperthermiatreatment. During the treatment, continuous supervision by trained personnel is guaranteed, and a doctor is on call.

Other names: passive whole body hyperthermia, water filtered whole body hyperthermia, moderate whole body infrared-A hyperthermia

Primary outcomes

  1. Circadian core body temperature

    Time frame: Week 0

    A BodyCap HF (high-frequency) measurement capsule is used for circadian monitoring of core body temperature over a 24-hour period. The single-use capsule is swallowed and excreted naturally after the measurement.

  2. Circadian core body temperature

    Time frame: Week 5

    A BodyCap HF (high-frequency) measurement capsule is used for circadian monitoring of core body temperature over a 24-hour period. The single-use capsule is swallowed and excreted naturally after the measurement.

  3. Cold detection threshold (CDT); °C

    Time frame: Week 0

    CDT is a part of quantitative sensory testing. A psychophysical testing method in which calibrated cold temperature stimuli (Thermode) 3x applied to the skin. Z-values are calculate.

  4. Cold detection threshold (CDT); °C

    Time frame: week 5

    CDT is a part of quantitative sensory testing. A psychophysical testing method in which calibrated cold temperature stimuli (Thermode) 3x applied to the skin. Z-values are calculate.

  5. Warm detection threshold (WDT); °C

    Time frame: Week 0

    WDT is a part of quantitative sensory testing. A psychophysical testing method in which calibrated warm temperature stimuli (Thermode) 3x applied to the skin. Z-values are calculate.

  6. Warm detection threshold (WDT); °C

    Time frame: week 5

    WDT is a part of quantitative sensory testing. A psychophysical testing method in which calibrated warm temperature stimuli (Thermode) 3x applied to the skin. Z-values are calculate.

  7. Thermal sensory limen (TSL) ; °C

    Time frame: week 0

    TSL is a part of quantitative sensory testing. A psychophysical testing method in which calibrated warm and cold temperature stimuli (Thermode) alternately 6x applied to the skin. Z-values are calculate and count number of cold stimuli that are perceived as hot.

  8. Thermal sensory limen (TSL) ; °C

    Time frame: week 5

    TSL is a part of quantitative sensory testing. A psychophysical testing method in which calibrated warm and cold temperature stimuli (Thermode) alternately 6x applied to the skin. Z-values are calculate and count number of cold stimuli that are perceived as hot.

  9. Cold pain threshold (CPT); °C

    Time frame: week 0

    CPT is a part of quantitative sensory testing. A psychophysical testing method in which calibrated nociceptive cold temperature stimuli (Thermode) 3x applied to the skin. Z-values are calculate.

  10. Cold pain threshold (CPT); °C

    Time frame: week 5

    CPT is a part of quantitative sensory testing. A psychophysical testing method in which calibrated nociceptive cold temperature stimuli (Thermode) 3x applied to the skin. Z-values are calculate.

  11. Heat pain threshold (HPT); °C

    Time frame: week 0

    HPT is a part of quantitative sensory testing. A psychophysical testing method in which calibrated nociceptive heat temperature stimuli (Thermode) 3x applied to the skin. Z-values are calculate.

  12. Heat pain threshold (HPT); °C

    Time frame: week 5

    HPT is a part of quantitative sensory testing. A psychophysical testing method in which calibrated nociceptive heat temperature stimuli (Thermode) 3x applied to the skin. Z-values are calculate.

  13. Mechanical detection threshold (MDT) ; mN

    Time frame: week 0

    MDT is a part of quantitative sensory testing. A psychophysical testing method in which calibrated mechanical stimuli (different strengths Frey filaments) 10x applied to the skin Z-values are calculated.

  14. Mechanical detection threshold (MDT) ; mN

    Time frame: week 5

    MDT is a part of quantitative sensory testing. A psychophysical testing method in which calibrated mechanical stimuli (different strengths Frey filaments) 10x applied to the skin Z-values are calculated.

  15. Mechanical pain threshold (MPT), count of sharp and blunt stimuli

    Time frame: week 0

    MPT is a part of quantitative sensory testing. A psychophysical testing method in which calibrated mechanical stimuli (PinPrick with different weights) 10x applied to the skin. Mechanical pain threshold (MPT). Count number of sharp and blunt stimuli. Z-values are calculated.

  16. Mechanical pain threshold (MPT), count of sharp and blunt stimuli

    Time frame: week 5

    MPT is a part of quantitative sensory testing. A psychophysical testing method in which calibrated mechanical stimuli (PinPrick with different weights) 10x applied to the skin. Mechanical pain threshold (MPT). Count number of sharp and blunt stimuli. Z-values are calculated.

  17. Mechanical pain sensitivity (MPS) ; NRS

    Time frame: week 0

    MPS is a part of quantitative sensory testing. A psychophysical testing method in which calibrated mechanical stimuli (PinPrick with different weights) 35x applied to the skin. The Numeric Rating Scale (0 = no pain to 100 = worst pain imaginable) is queried. Z-values are calculated.

  18. Mechanical pain sensitivity (MPS) ; NRS

    Time frame: week 5

    MPS is a part of quantitative sensory testing. A psychophysical testing method in which calibrated mechanical stimuli (PinPrick with different weights) 35x applied to the skin. The Numeric Rating Scale (0 = no pain to 100 = worst pain imaginable) is queried. Z-values are calculated.

  19. Summative pain amplification (WUR); NRS

    Time frame: week 0

    WUR (wind-up ratio) is a part of quantitative sensory testing. A psychophysical testing method in which calibrated mechanical stimuli (PinPrick with different weights) single and seriell 10x applied to the skin. The Numeric Rating Scale (0 = no pain to 100 = worst pain imaginable) for single and seriell stimuli are compared into relation. Z-values are calculated.

  20. Summative pain amplification (WUR); NRS

    Time frame: week 5

    WUR (wind-up ratio) is a part of quantitative sensory testing. A psychophysical testing method in which calibrated mechanical stimuli (PinPrick with different weights) single and seriell 10x applied to the skin. The Numeric Rating Scale (0 = no pain to 100 = worst pain imaginable) for single and seriell stimuli are compared into relation. Z-values are calculated.

  21. Vibration detection threshold (VDT) ; x/8

    Time frame: week 0

    VDT is a part of quantitative sensory testing. A psychophysical testing method in which calibrated mechanical stimuli (64Hz tuning fork) 3x applied to the skin. The x/8 vibration is measure (0/8 no perception and 8/8 strengthest perception). Z-values are calculated.

  22. Vibration detection threshold (VDT) ; x/8

    Time frame: week 5

    VDT is a part of quantitative sensory testing. A psychophysical testing method in which calibrated mechanical stimuli (64Hz tuning fork) 3x applied to the skin. The x/8 vibration is measure (0/8 no perception and 8/8 strengthest perception). Z-values are calculated.

  23. Pressure pain threshold (PPT), kgf/1cm2

    Time frame: week 0

    PPT is a part of quantitative sensory testing. A psychophysical testing method in which calibrated mechanical stimuli (pain pressure algometer) 5x applied to the skin. Z-values are calculated.

  24. Pressure pain threshold (PPT), kgf/1cm2

    Time frame: week 5

    PPT is a part of quantitative sensory testing. A psychophysical testing method in which calibrated mechanical stimuli (pain pressure algometer) 5x applied to the skin. Z-values are calculated.

  25. Dynamic mechanical allodynia (DMA), NRS

    Time frame: week 0

    DMA is a part of quantitative sensory testing. A psychophysical testing method in which calibrated mechanical stimuli (brush, cotton wool and Q-Tip) 5x applied to the skin. Z-values are calculated. The Numeric Rating Scale (0 = no pain to 100 = worst pain imaginable) ist queried. Z-values are calculated.

  26. Dynamic mechanical allodynia (DMA), NRS

    Time frame: week 5

    DMA is a part of quantitative sensory testing. A psychophysical testing method in which calibrated mechanical stimuli (brush, cotton wool and Q-Tip) 5x applied to the skin. Z-values are calculated. The Numeric Rating Scale (0 = no pain to 100 = worst pain imaginable) ist queried. Z-values are calculated.

  27. 6-Minute Walk Test (6MWT)

    Time frame: Week 0

    Walking back and forth as far as possible along a 30-meter corridor in 6 minutes, taking breaks as needed ( total distance covered is recorded in meters, pain is measured before and after the test, 0 = no pain, 10 = worst pain imaginable)

  28. 6-Minute Walk Test (6MWT)

    Time frame: Week 5

    Walking back and forth as far as possible along a 30-meter corridor in 6 minutes, taking breaks as needed ( total distance covered is recorded in meters, pain is measured before and after the test, 0 = no pain, 10 = worst pain imaginable)

Secondary outcomes

  1. McGill Pain Questionnaire (MPQ)

    Time frame: Week 0

    The instrument assesses subjective pain experience and evaluates both the quality and numerical intensity of pain (0 = no pain; 10 = worst pain imaginable)

  2. McGill Pain Questionnaire (MPQ)

    Time frame: Week 5

    The instrument assesses subjective pain experience and evaluates both the quality and numerical intensity of pain (0 = no pain; 10 = worst pain imaginable)

  3. McGill Pain Questionnaire (MPQ)

    Time frame: Week 12

    The instrument assesses subjective pain experience and evaluates both the quality and numerical intensity of pain (0 = no pain; 10 = worst pain imaginable)

  4. McGill Pain Questionnaire (MPQ)

    Time frame: Week 30

    The instrument assesses subjective pain experience and evaluates both the quality and numerical intensity of pain (0 = no pain; 10 = worst pain imaginable)

  5. Fear Avoidance Beliefs Questionnaire (FABQ)

    Time frame: Week 0

    Is a psychological questionnaire designed to assess a person's beliefs about how physical activity and work may influence their pain. It focuses on fear-avoidance behaviours, particularly in individuals with musculoskeletal pain (e.g., low back pain). The questionnaire consists of 16 items divided into two subscales: physical activity (FABQ-PA) and work (FABQ-W). Items are rated on a 7-point Likert scale (from "completely disagree" to "completely agree").

  6. Fear Avoidance Beliefs Questionnaire (FABQ)

    Time frame: Week 5

    Is a psychological questionnaire designed to assess a person's beliefs about how physical activity and work may influence their pain. It focuses on fear-avoidance behaviours, particularly in individuals with musculoskeletal pain (e.g., low back pain). The questionnaire consists of 16 items divided into two subscales: physical activity (FABQ-PA) and work (FABQ-W). Items are rated on a 7-point Likert scale (from "completely disagree" to "completely agree").

  7. Fear Avoidance Beliefs Questionnaire (FABQ)

    Time frame: Week 12

    Is a psychological questionnaire designed to assess a person's beliefs about how physical activity and work may influence their pain. It focuses on fear-avoidance behaviours, particularly in individuals with musculoskeletal pain (e.g., low back pain). The questionnaire consists of 16 items divided into two subscales: physical activity (FABQ-PA) and work (FABQ-W). Items are rated on a 7-point Likert scale (from "completely disagree" to "completely agree").

  8. Fear Avoidance Beliefs Questionnaire (FABQ)

    Time frame: Week 30

    Is a psychological questionnaire designed to assess a person's beliefs about how physical activity and work may influence their pain. It focuses on fear-avoidance behaviours, particularly in individuals with musculoskeletal pain (e.g., low back pain). The questionnaire consists of 16 items divided into two subscales: physical activity (FABQ-PA) and work (FABQ-W). Items are rated on a 7-point Likert scale (from "completely disagree" to "completely agree").

  9. Multidimensional Fatigue Inventory (MFI-20)

    Time frame: Week 0

    An inventory including 20 questions about fatigue-symptoms (each from 1 ("Yes, that is true") to 5 ("No, that is not true")) covering 5 dimensions (general fatigue, physical fatigue, reduced motivation, reduced activity, mental fatigue)

  10. Multidimensional Fatigue Inventory (MFI-20)

    Time frame: Week 5

    An inventory including 20 questions about fatigue-symptoms (each from 1 ("Yes, that is true") to 5 ("No, that is not true")) covering 5 dimensions (general fatigue, physical fatigue, reduced motivation, reduced activity, mental fatigue)

  11. Multidimensional Fatigue Inventory (MFI-20)

    Time frame: Week 12

    An inventory including 20 questions about fatigue-symptoms (each from 1 ("Yes, that is true") to 5 ("No, that is not true")) covering 5 dimensions (general fatigue, physical fatigue, reduced motivation, reduced activity, mental fatigue)

  12. Multidimensional Fatigue Inventory (MFI-20)

    Time frame: Week 30

    An inventory including 20 questions about fatigue-symptoms (each from 1 ("Yes, that is true") to 5 ("No, that is not true")) covering 5 dimensions (general fatigue, physical fatigue, reduced motivation, reduced activity, mental fatigue)

  13. General Depression Scale (ADS-L)

    Time frame: Week 0

    is a german self-report questionnaire designed to assess depressive symptoms in the general population adapted from the CES-D. (20 items, 4-point Likert scale (0 = rarely or none of the time, 3 = most or all of the time)

  14. General Depression Scale (ADS-L)

    Time frame: Week 5

    is a german self-report questionnaire designed to assess depressive symptoms in the general population adapted from the CES-D. (20 items, 4-point Likert scale (0 = rarely or none of the time, 3 = most or all of the time)

  15. General Depression Scale (ADS-L)

    Time frame: Week 12

    is a german self-report questionnaire designed to assess depressive symptoms in the general population adapted from the CES-D. (20 items, 4-point Likert scale (0 = rarely or none of the time, 3 = most or all of the time)

  16. General Depression Scale (ADS-L)

    Time frame: Week 30

    is a german self-report questionnaire designed to assess depressive symptoms in the general population adapted from the CES-D. (20 items, 4-point Likert scale (0 = rarely or none of the time, 3 = most or all of the time)

  17. Avoidance-Endurance Fast-Screen (AEFS)

    Time frame: week 0

    Description: Is a short screening questionnaire designed to identify maladaptive pain coping patterns, specifically avoidance and endurance behaviours in individuals with musculoskeletal pain. It differentiates between fear-avoidance responses and endurance-related coping styles (e.g., persistence despite pain).

    The AEFS includes a 7-point scale (0=never to 6=always) for Pain Persistence (PPS) from the Avoidance-Endurance Questionnaire (AEQ), as well as two dichotomous (0=yes, 1=no) mood items from the Beck-Depressions-Inventar. The PPS scale is administered using two response scales for coping with mild and severe pain.

  18. Avoidance-Endurance Fast-Screen (AEFS)

    Time frame: week 5

    Description: Is a short screening questionnaire designed to identify maladaptive pain coping patterns, specifically avoidance and endurance behaviours in individuals with musculoskeletal pain. It differentiates between fear-avoidance responses and endurance-related coping styles (e.g., persistence despite pain).

    The AEFS includes a 7-point scale (0=never to 6=always) for Pain Persistence (PPS) from the Avoidance-Endurance Questionnaire (AEQ), as well as two dichotomous (0=yes, 1=no) mood items from the Beck-Depressions-Inventar. The PPS scale is administered using two response scales for coping with mild and severe pain.

  19. Avoidance-Endurance Fast-Screen (AEFS)

    Time frame: week 12

    Description: Is a short screening questionnaire designed to identify maladaptive pain coping patterns, specifically avoidance and endurance behaviours in individuals with musculoskeletal pain. It differentiates between fear-avoidance responses and endurance-related coping styles (e.g., persistence despite pain).

    The AEFS includes a 7-point scale (0=never to 6=always) for Pain Persistence (PPS) from the Avoidance-Endurance Questionnaire (AEQ), as well as two dichotomous (0=yes, 1=no) mood items from the Beck-Depressions-Inventar. The PPS scale is administered using two response scales for coping with mild and severe pain.

  20. Avoidance-Endurance Fast-Screen (AEFS)

    Time frame: week 30

    Description: Is a short screening questionnaire designed to identify maladaptive pain coping patterns, specifically avoidance and endurance behaviours in individuals with musculoskeletal pain. It differentiates between fear-avoidance responses and endurance-related coping styles (e.g., persistence despite pain).

    The AEFS includes a 7-point scale (0=never to 6=always) for Pain Persistence (PPS) from the Avoidance-Endurance Questionnaire (AEQ), as well as two dichotomous (0=yes, 1=no) mood items from the Beck-Depressions-Inventar. The PPS scale is administered using two response scales for coping with mild and severe pain.

Other outcomes

  1. BDNF

    Time frame: Week 0

    Brain-Derived Neurotrophic Factor (BDNF) in blood to measure nociplasticity

  2. BDNF

    Time frame: Week 5

    Brain-Derived Neurotrophic Factor (BDNF) in blood to measure nociplasticity

  3. PRISE (Patient-Rated Inventory of Side Effects)

    Time frame: 30min post treatment

    A tool used to assess the presence and severity of side effects (0=no severity, 3= greater severity) across nine organ/function domains, including gastrointestinal, nervous system, heart, eyes/ears, skin, genital/urinary, sleep, sexual function, and other areas

Study contacts

Contact information is provided by the study sponsor or research team.

Kay-Uwe Hanusch, Dr.scient.med

CONTACT

[email protected]

+41 31 848 5005

Sponsors and collaborators

Lead sponsor

Bern University of Applied Sciences

Other

Collaborators

  • Dr. med. h.c Erwin Braun Stiftung

Registry information

Official study title

Hyperthermia in Healthy and Patients With Chronic Primary Pain - Effects on Thermoregulation, Somatosensory System, Movement Evoked Pain (HYPPRI-1)

Acronym: HYPPRI-1

Important dates

Study start
2026
Primary completion
2028
Study completion
2028
First posted
Aug 3, 2025
Registry last updated
Jun 2, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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