Local head and neck cooling strategies can help reduce multiple sclerosis-related fatigue, while heating can exacerbate heat-related fatigue. However, no study has detailed the peripheral and central responses to head and neck cooling (at 18°C) and heating (at 43 ± 1°C next to the scalp and neck skin) during fatiguing isometric exercise in non-challenging ambient temperature in multiple sclerosis and healthy male subjects. In addition, there is a lack of data describing the effects of head and neck cooling/heating and strenuous exercise on blood markers, muscle temperature, motor accuracy, and rate of perceived exertion. The investigators hypothesized that: (i) men with multiple sclerosis would be more affected by central and peripheral fatigue compared to healthy subjects; (ii) local cooling will result in greater central fatigue but will be associated with greater peripheral fatigue, whereas heating will result in greater central and peripheral fatigue in multiple sclerosis men; (iv) local cooling and heating will have a greater effect on the release of stress hormones, rate of perceived exertion and motor accuracy compared to the control condition in both multiple sclerosis and healthy groups.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
40
Cooling of the head and neck at 18°C next to the head and neck skin in multiple sclerosis and healthy subjects
Heating of the head and neck at 43 ± 1°C next to the head and neck skin in multiple sclerosis
Lithuanian Sports University
Kaunas, Lithuania
Body weight (kg)
Body weight (kg) was evaluated using Tanita Body Composition Analyzer (Japan).
Time frame: Every time in all conditions at the baseline
Body fat (%)
Body fat (%) was assessed using Tanita Body Composition Analyzer (Japan).
Time frame: Every time in all conditions at the baseline
Body free fat mass (kg)
Body free fat mass (kg) was evaluated using Tanita Body Composition Analyzer (Japan).
Time frame: Every time in all conditions at the baseline
Body mass index (kg/m2)
The body mass index (in kg/m2) was defined as the body mass divided by the square of the body height.
Time frame: Every time in all conditions at the baseline
Change in muscle temperature (°C)
Muscle temperature was measured using a needle microprobe (Intramuscular Probe MKA, thermometer model DM-852, Ellab) inserted approximately 3 cm beneath the skin surface into the vastus lateralis muscle of the right leg.
Time frame: Baseline, up to 60 minutes, up to 120 minutes, after 180minutes
Change in plasma cortisol (nmol/L) concentrations
Plasma cortisol concentrations (nmol/L) were measured using an AIA-2000 automated enzyme immunoassay analyser (Tosoh Corp, Tokyo, Japan).
Time frame: Baseline, up to 60 minutes, up to 120 minutes, after 180minutes
Change in plasma dopamine (nmol/L) concentrations
Dopamine concentrations (nmol/L) were measured using a kit for dopamine enzyme-linked immunosorbent assay (ELISA) (IBL, Hamburg, Germany).
Time frame: Baseline, up to 60 minutes, up to 120 minutes, after 180minutes
Change in plasma prolactin (ng/mL) concentrations
Prolactin levels (ng/mL) were measured using a kit for prolactin ELISA (IBL) and Gemini analyzer (Stratec Biomedical GmbH, Germany).
Time frame: Baseline, up to 60 minutes, up to 120 minutes, after 180minutes
Change in subjective rating of perceived exertion
Perceived exertion was assessed using the Borg scale, ranging from 6 (no exertion) to 20 (maximum exertion).
Time frame: Baseline, up to 60 minutes, up to 120 minutes, after 180minutes
Change in muscle activity (mV)
Vastus medialis and vastus lateralis electromyographic (EMG) amplitude (in mV) parameters of muscular activity were measured using surface EMG (Biometrics, UK) thorough neuromuscular function assessment.
Time frame: Baseline, up to 60 minutes, up to 120 minutes, after 180minutes
Change in muscle activity (Hz)
Vastus medialis and vastus lateralis muscles electromyographic (EMG) frequency (in Hz) parameters of muscular activity were measured using surface EMG (Biometrics, UK) thorough neuromuscular function assessment.
Time frame: Baseline, up to 60 minutes, up to 120 minutes, after 180minutes
Change in voluntary torque (Nm)
Isometric and isokinetic voluntary torques (in Nm) of the quadriceps muscles were measured using an isokinetic dynamometer (Biodex Medical Systems, USA).
Time frame: Baseline, up to 60 minutes, up to 120 minutes, after 180minutes
Change in involuntary torque (Nm)
Involuntary torque of the quadriceps muscles were measured using an isokinetic dynamometer (Biodex Medical Systems, USA) and a high-voltage stimulator (Digitimer DS7A, Digitimer, UK). Peak torques (in Nm) induced by electrical stimulation at 20 Hz,at 100 Hz, and at TT100 were measured.
Time frame: Baseline, up to 60 minutes, up to 120 minutes, after 180minutes
Change in muscle contraction and relaxation (ms)
The contraction and half-relaxation time (in ms) were measured in 100Hz stimulated contractions.
Time frame: Baseline, up to 60 minutes, up to 120 minutes, after 180minutes
Change in central activation ratio (percent)
To evaluate central activation ratio (CAR), a TT-100 Hz stimuli was superimposed on the maximal voluntary contraction (MVC), and the CAR was computed using the following equation: CAR = MVC/(MVC+TT-100 Hz) × 100percent, where where a CAR of 100 percent indicates complete activation of the exercising muscle and a CAR \< 100 percent indicates central activation failure or inhibition.
Time frame: Baseline, up to 60 minutes, up to 120 minutes, after 180minutes
Change in constant error
The accuracy of the intermittent isometric contraction tasks was calculated as a constant error. Constant error = ∑(xi - T)/n where xi is the motor task performed (N·m); T is the target quantity, i.e., the motor task required; n is the number of trials; and Σ indicates the mean that was calculated considering the algebraic symbols (±).
Time frame: Baseline, up to 60 minutes, up to 120 minutes, after 180minutes
Change in absolute error
The absolute error specifies the absolute deviation from the required target force. Absolute error = ∑\|xi - T\|/n where xi is the motor task performed (N·m); T is the target quantity, i.e., the motor task required; n is the number of trials; and vertical brackets Σ \| \| indicate the mean that was calculated without considering the algebraic symbols (±).
Time frame: Baseline, up to 60 minutes, up to 120 minutes, after 180minutes
Height (m)
Height (in m) was measured using a Harpenden anthropometer set (Holtain Ltd, UK)
Time frame: Every time in all conditions at the baseline
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