To examine the thermophysiological responses to prolonged exercise in hot and humid environmental conditions in patients with a history of exertional heat stroke or malignant hyperthermia susceptibility and compare the thermophysiological responses…
ID
Source
Brief title
Condition
- Other condition
Synonym
Health condition
Thermoregulatoire aandoeningen (hitteberoerte en maligne hyperthermie)
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
The primary outcome of this study is the increase in core temperature (CBT)
during exercise at a fixed metabolic heat production.
Secondary outcome
Secondary outcomes relate to the thermoregulatory (i.e. skin temperature, heat
production, sweat rate, heat balance) and cardiovascular responses (i.e. heart
rate, blood pressure) to exercise in hot environmental conditions.
Background summary
Exercise is, due to the inefficient energy production, known to increase core
body temperature (CBT), which could lead to substantial reductions in exercise
performance and it increases the risk to develop heat-related illnesses such as
heat exhaustion and heatstroke. Exertional heat stroke (EHS) is defined as a
core temperature (>40.5°C) in combination with central nervous dysfunction
resulting from exposure to environmental heat and strenuous physical exercise.
EHS can be extremely dangerous, as it could lead to multiple organ failure,
coma or even death. Previous literature suggested that some predisposing
factors may put individuals at increased risk of EHS. However, the exact
mechanism why some individuals suffer from events of EHS during a specific
exercise and environment, while others do not, is not yet known. A related
medical condition associated with dysregulation of the thermoregulatory system
is malignant hyperthermia (MH). MH is a well described pharmacogenetic disorder
with autosomal dominant inheritance. It clinically manifests as a
hypermetabolic crisis when an MH-susceptible (MHS) individual is exposed to
volatile anesthetics or depolarizing muscle relaxants. Previous literature
suggested that EHS may be related to MH, taking into account the overlap in
symptomatology. However, it remains unclear whether patients susceptible to MH
or EHS have an altered thermophysiological response to prolonged exercise
challenging environmental conditions compared to healthy controls.
Study objective
To examine the thermophysiological responses to prolonged exercise in hot and
humid environmental conditions in patients with a history of exertional heat
stroke or malignant hyperthermia susceptibility and compare the
thermophysiological responses with healthy age-matched controls.
Study design
Explorative intervention study.
Study burden and risks
Participants will visit the Radboudumc twice; medical screening and submaximal
exercise test during visit 1 and providing a blood sample during visit 2. The
burden of the exercise test is low, since all participants are accustomed to
regular exercise training (endurance exercise *2x per week). For safety
reasons, participants will be closely monitored during the exercise test. The
test can be aborted when termination criteria (i.e. CBT *40°C) are met or if
the participants decide to stop. Moreover, cooling interventions will be
available when a participant develops symptoms of a heat-related illness.
Furthermore, blood will be drawn from an antecubital vein, which may
occasionally (<5%) result in a hematoma that will disappear usually within a
week. Taken together, the burden and risks of the present study can be
considered as negligible.
Philips van Leijdenlaan 15
Nijmegen 6525EX
NL
Philips van Leijdenlaan 15
Nijmegen 6525EX
NL
Listed location countries
Age
Inclusion criteria
- Between 18 and 60 years of age
- Willingness to provide written consent after proper information about the
study objectives and procedures
- Physically active lifestyle (endurance exercise, *2 times a week)
Furthermore, we will apply specific inclusion criteria for the EHS and MHS
group.
- EHS group: a history of an EHS in the past 10 years that has resulted in
physical complaints for at least 6 months.
- MH group: a history of RYR1-related MH or MH susceptibility (MHS) according
to the guidelines of the European Malignant Hyperthermia Group (EMHG), which
states that an individual is MHS when an individual have a diagnostically
confirmed RYR1 variant or a positive in vitro contracture test. Only one member
per family will be included in order to ensure that we include a representative
sample of the MHS population.
- Control group: healthy age and sex matched peers.
Exclusion criteria
A potential participant who meets any of the following criteria will be
excluded from participation in this study:
- Exclusion criteria associated with the use of the telemetric temperature
capsule: I) a bodyweight <36.5 kg, II) an implanted electro-medical device,
III) a history of obstructive/inflammatory bowel disease or surgery, IV) or a
scheduled MRI scan within 5 days of the experiment.
- Medication use that alters thermoregulatory function (i.e. diuretics,
laxatives and antihypertensives (disturbed fluid balance), anticholinergics and
antiepileptics (reduced sweating), corticosteroids (impairs immune response and
cytokine release), sympathomimetics (reduced vasomotor control), antipsychotics
(disturbed thermoregulation in hypothalamus and reduced sweating)).
Additional exclusion criteria for the control group:
- A (family) history of EHS or MH
- A (family) history of suspected MH reactions
- A family history of RYR1 related myopathies (e.g. central core disease,
King-Denborough Syndrome or multi mini core disease).
- A family history of an unexplained peri-operative dead
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL76228.091.20 |