Spinal cord injury (SCI), causes loss of supra-spinal control of the sympathetic nervous system and in some cases loss of sensation. As a result, people with SCI have impaired thermoregulatory system and the consequence of this thermoregulatory dysfunction, is that they cannot respond to the environmental changes. All the above lead to dysregulation in vasomotor tone, skeletal muscle shivering and sweating dysfunction. It is well known that skin plays an important role in regulating body temperature and regulates interactions between the environment and human body. A previous study in people with incomplete SCI showed that there are no differences in core temperature between patients with different level of mobility and sensation and different level of lesion, but there are significant differences in skin temperature. As mentioned above people with SCI have an impaired thermoregulatory capacity due to sudomotor and vasomotor dysfunction and that leads to greater thermal strain during rest and exercise when they expose to hot conditions. A previous study that performed exercise in people with SCI, highlights the fact that because of the impaired evaporative heat loss during exercise in hot conditions, they are in great risk. Because of this risk they propose different cooling strategies that promote evaporation such as fans and water spraying. It is therefore important to observe the thermoregulatory function (vasomotion and sudomotor) in people with SCI when they are exposed to different environments (cold, neutral and warm).
The participants will visit the laboratory three times. At each time the environmental chamber will simulate a different environment in a random order for each participant. The three different environments will be as follow: 1. Cold environment 15-17°C and 40-50% relative humidity 2. Thermoneutral environment 22-24°C and 40-50% relative humidity 3. Warm environment 33-35°C and 40-50% relative humidity The participants will stay in a sited position for 20 minutes in order to collect baseline data and to allow to their blood flow and body temperature adapt to the exposing environmental condition each time. Immediately after the baseline period the participants will immerse their left hand and foot in warm water (34-36°C) for 5 minutes for a consistent starting (hand and foot) temperature. Following that participants will immerse their hand and foot in cold water (8°C) for 40 minutes. This procedure will be repeated in every measurement and it will only change the environment. Anthropometric data \[self-reported age, self-reported body stature and body mass (DXA, Lunar, GE Healthcare Boston, Massachusetts, U.S)\] will be collecting at the beginning of the first measurement. Medical history of all the participants will be recording. During the study, continuous heart rate (Polar Team2. Polar Electro Oy, Kempele, Finland), core temperature (telemetric capsules BodyCap, Caen, France), mean skin temperature (wireless thermistors iButtons type DS1921H, Maxim/Dallas Semiconductor Corp., USA), finger temperature ((Smartreader 8 Plus, ACR, Vancouver, Canada), skin blood flow and sweat rate data (laser Doppler flow-meter PeriFlux System 5010, function unit; Perimed, Stockholm, Sweden and PeriFlux System 4002, master unit, satellite unit; Perimed, Stockholm, Sweden) will be collecting. Blood pressure will also be monitoring every 10 minutes with an automatic sphygmomanometer (Omron Healthcare M6 comfort, Japan). Skin temperature data will be collecting from four sites (chest, arm, thigh, and leg) and will be expressed as mean skin temperature according to the formula of Ramanathan (Tsk = \[0.3(chest + arm) + 0.2(thigh + leg)\]. Questionnaires (thermal sensation scale: -3 = cold; +3 = hot) will be used to assess participants' thermal comfort/sensation and pain.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
16
In a cold environment (15-17°C and 40-50% relative humidity), participants will stay in a sited position for 20 minutes in order to collect baseline data and to allow their blood flow and body temperature adapt to the exposing environmental condition. Immediately after the baseline period participants will immerse their left hand and foot in warm water (34-36°C) for five minutes for a consistent starting (hand and foot) temperature. Following that participants will immerse their hand and foot in cold water (8°C) for 40 minutes.
In a thermoneutral environment (22-24°C and 40-50% relative humidity), participants will stay in a sited position for 20 minutes in order to collect baseline data and to allow their blood flow and body temperature adapt to the exposing environmental condition. Immediately after the baseline period participants will immerse their left hand and foot in warm water (34-36°C) for five minutes for a consistent starting (hand and foot) temperature. Following that participants will immerse their hand and foot in cold water (8°C) for 40 minutes.
In a warm environment (33-35°C and 40-50% relative humidity), participants will stay in a sited position for 20 minutes in order to collect baseline data and to allow their blood flow and body temperature adapt to the exposing environmental condition. Immediately after the baseline period participants will immerse their left hand and foot in warm water (34-36°C) for five minutes for a consistent starting (hand and foot) temperature. Following that participants will immerse their hand and foot in cold water (8°C) for 40 minutes.
In a cold environment (15-17°C and 40-50% relative humidity), participants will stay in a sited position for 20 minutes in order to collect baseline data and to allow their blood flow and body temperature adapt to the exposing environmental condition. Immediately after the baseline period participants will immerse their left hand and foot in warm water (34-36°C) for five minutes for a consistent starting (hand and foot) temperature. Following that participants will immerse their hand and foot in cold water (8°C) for 40 minutes.
In a thermoneutral environment (22-24°C and 40-50% relative humidity), participants will stay in a sited position for 20 minutes in order to collect baseline data and to allow their blood flow and body temperature adapt to the exposing environmental condition. Immediately after the baseline period participants will immerse their left hand and foot in warm water (34-36°C) for five minutes for a consistent starting (hand and foot) temperature. Following that participants will immerse their hand and foot in cold water (8°C) for 40 minutes.
In a warm environment (33-35°C and 40-50% relative humidity), participants will stay in a sited position for 20 minutes in order to collect baseline data and to allow their blood flow and body temperature adapt to the exposing environmental condition. Immediately after the baseline period participants will immerse their left hand and foot in warm water (34-36°C) for five minutes for a consistent starting (hand and foot) temperature. Following that participants will immerse their hand and foot in cold water (8°C) for 40 minutes.
In a cold environment (15-17°C and 40-50% relative humidity), participants will stay in a sited position for 20 minutes in order to collect baseline data and to allow their blood flow and body temperature adapt to the exposing environmental condition. Immediately after the baseline period participants will immerse their left hand and foot in warm water (34-36°C) for five minutes for a consistent starting (hand and foot) temperature. Following that participants will immerse their hand and foot in cold water (8°C) for 40 minutes.
In a thermoneutral environment (22-24°C and 40-50% relative humidity), participants will stay in a sited position for 20 minutes in order to collect baseline data and to allow their blood flow and body temperature adapt to the exposing environmental condition. Immediately after the baseline period participants will immerse their left hand and foot in warm water (34-36°C) for five minutes for a consistent starting (hand and foot) temperature. Following that participants will immerse their hand and foot in cold water (8°C) for 40 minutes.
In a warm environment (33-35°C and 40-50% relative humidity), participants will stay in a sited position for 20 minutes in order to collect baseline data and to allow their blood flow and body temperature adapt to the exposing environmental condition. Immediately after the baseline period participants will immerse their left hand and foot in warm water (34-36°C) for five minutes for a consistent starting (hand and foot) temperature. Following that participants will immerse their hand and foot in cold water (8°C) for 40 minutes.
FAME Lab, Department of Exercise Science, University of Thessaly
Trikala, Thessaly, Greece
Heart rate
Heart rate will be continuously monitored using a Polar Team system (Polar® Team 2, Polar Electro Oy, Kempele, Finland
Time frame: 1 hour and 5 minutes
Heart rate variability
Heart rate variability will be continuously monitored using a Polar Team system (Polar® Team 2, Polar Electro Oy, Kempele, Finland
Time frame: 1 hour and 5 minutes
Skin temperature
Skin temperature (chest, arm, thigh, and leg) will be continuously monitored using iButton sensors type DS1921 H, Maxim/Dallas Semiconductor Corp., USA.
Time frame: 1 hour and 5 minutes
Finger temperature
Finger temperature will be monitored throughout baseline and water immersion at 8-s intervals using a data logger (Smartreader 8 Plus, ACR, Vancouver, Canada) interfacing with a computer to allow for their continuous monitoring by the investigators.
Time frame: 1 hour and 5 minutes
Body core temperature
Core body temperature will be assessed using telemetric capsules (e-Celsius, BodyCap, Caen, France) that we will give to the participants to ingest prior to the measurement.
Time frame: 1 hour and 5 minutes
Skin blood flow
Skin blood flow will be monitored via laser Doppler flowmeter (PeriFlux System 5010, function unit; Perimed, Stockholm, Sweden and PeriFlux System 4002, master unit, satellite unit; Perimed, Stockholm, Sweden)
Time frame: 1 hour and 5 minutes
Change of blood pressure
Blood pressure will be monitored every 10 minutes with an automatic sphygmomanometer (Omron Healthcare M6 comfort, Japan)
Time frame: Change from baseline blood pressure at 10th, 20th, 30th, 40th, 50th and 65th minute.
Sweat rate
Sweat rate will be measured using a 5.0-cm2 ventilated capsule placed over the forehead and the gastrocnemius. Anhydrous compressed air will be passing through the capsule and over the skin surface (Brooks 5850, mass flow controller, Emerson Electric, Hetfield, PA, USA). The vapor density of the effluent air will be calculating from the relative humidity and temperature measured using the Omega HX93 humidity and temperature sensor (Omega Engineering, Stanford, CT, USA). Sweat rate will be defined as the product of the difference in water content between effluent and influent air and the flow rate. The flow rate through the capsule is 1.13 L min-1. The sweat rate value will be adjusted for skin surface area under the capsule (expressed in mg min-1 cm-2).
Time frame: 1 hour and 5 minutes
Change of thermal comfort
Thermal comfort was assessed via the thermal comfort scale (1 = comfortable; 5 = extremely uncomfortable)
Time frame: Change from baseline thermal comfort at 10th, 20th, 30th, 40th, 50th and 65th minute.
Change of thermal sensation
Thermal sensation was assessed via the thermal sensation scale (-3 = cold; +3 = hot)
Time frame: Change from baseline thermal sensation at 10th, 20th, 30th, 40th, 50th and 65th minute.
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