• Safety and Health at Work
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• v.7 no.2
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• pp.124-129
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• 2016

Background: Work-related fatigue has a strong impact on performance and safety but so far, no agreed upon method exists to detect and quantify it. It has been suggested that work-related fatigue cannot be quantified with just one test alone, possibly because fatigue is not a uniform construct. The purpose of this study is therefore to measure work-related fatigue with multiple tests and then to determine the underlying factorial structure. Methods: Twenty-eight employees (mean: 36.11; standard deviation 13.17) participated in five common fatigue tests, namely, posturography, heart rate variability, distributed attention, simple reaction time, and subjective fatigue before and after work. To evaluate changes from morning to afternoon, t tests were conducted. For further data analysis, the differences between afternoon and morning scores for each outcome measure and participant (${\Delta}$ scores) were submitted to factor analysis with varimax rotation and each factor with the highest-loading outcome measure was selected. The ${\Delta}$ scores from tests with single and multiple outcome measures were submitted for a further factor analysis with varimax rotation. Results: The statistical analysis of the multiple tests determine a factorial structure with three factors: The first factor is best represented by center of pressure (COP) path length, COP confidence area, and simple reaction time. The second factor is associated with root mean square of successive difference and useful field of view (UFOV). The third factor is represented by the single ${\Delta}$ score of subjective fatigue. Conclusion: Work-related fatigue is a multidimensional phenomenon that should be assessed by multiple tests. Based on data structure and practicability, we recommend carrying out further studies to assess work-related fatigue with manual reaction time and UFOV Subtest 2.

• Safety and Health at Work
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• v.6 no.3
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• pp.256-262
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• 2015

Background: Heart attack is the most common cause of line-of-duty death in the fire service. Daily aspirin therapy is a preventative measure used to reduce the morbidity of heart attacks but may decrease the ability to dissipate heat by reducing skin blood flow. Methods: In this double-blind, placebo-controlled, crossover study, firefighters were randomized to receive 14 days of therapy (81-mg aspirin or placebo) before performing treadmill exercise in thermal-protective clothing in a hot room [$38.8{\pm}2.1^{\circ}C$, $24.9{\pm}9.1%$ relative humidity (RH)]. Three weeks without therapy was provided before crossing to the other arm. Firefighters completed a baseline skin blood-flow assessment via laser Doppler flowmetry; skin was heated to $44^{\circ}C$ to achieve maximal cutaneous vasodilation. Skin blood flow was measured before and after exercise in a hot room, and at 0 minutes, 10 minutes, 20 minutes, and 30 minutes of recovery under temperature conditions ($25.3{\pm}1.2^{\circ}C$, $40.3{\pm}13.7%\;RH$). Platelet clotting time was assessed before drug administration, and before and after exercise. Results: Fifteen firefighters completed the study. Aspirin increased clotting time before and after exercise compared with placebo (p = 0.003). There were no differences in absolute skin blood flow between groups (p = 0.35). Following exercise, cutaneous vascular conductance (CVC) was $85{\pm}42%$ of maximum in the aspirin and $76{\pm}37%$ in the placebo groups. The percentage of maximal CVC did not differ by treatment before or after recovery. Neither maximal core body temperature nor heart rate responses to exercise differed between trials. Conclusion: There were no differences in skin blood flow during uncompensable heat stress following exercise after aspirin or placebo therapy.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.3
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• pp.700-703
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• 2009

The present study investigated whether electroacupuncture (EA) can alleviate hypertension and concomitant disorders such as decreased kidney weight and elevation of serum creatinine in spontaneous hypertensive rats. EA (2 Hz, 3 mA, 10 min) was applied to Joksamni (ST36) once daily for 7 days. Body weight, blood pressure and heart rate were measured on Day 0, 2, 6, 8, 10 and 12, and kidney weight and serum creatinine levels were examined after sacrifice (on Day 12 after last examination). In the ST36 group, the blood pressure were significantly decreased from 6thdays and its effects lasted up to Day12 (up to 5days after cessation of acupuncture), compared to control. And, significant decreases of the heart rates after EA at ST36 were also observed on Day 2, 6, and 8. However, there were no significant differences in daily body weight, kidney weight and serum creatinine between acupuncture and control group. These results showed that EA at ST36 caused anti-hypertension by decreasing blood pressure and heart rates in spontaneous hypertenstive rats, although it failed to alleviate concomitant disorders such as the decreased kidney weight and elevation of serum creatinine shown in hypertensive rats.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.2
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• pp.316-321
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• 2002

CheonghunHwadam-tang(CHT) have been used in oriental medicine for many centuries as a therapeutic agent of vertigo by wind, fire and phlegm. CheonghunHwadam-tangGamypang(CHTG) was CHT adding Aurantii Fructus(AF), Gastrodae Rhizoma(GR). The effects of CHT on the cerebral blood flow and cardiacvascular system is not known. The purpose of this Study was to investigate effects of CHT and CHTG on the regional cerebral blood flow(rCBF), mean arterial blood pressure(BP), cardiac muscle contractile force(CMF), heart rate(HR). The changes of cerebral blood flow and movement of cardiacvascular system(BP, CMF, HR) was determinated by Laser-Doppler Rowmetry(LDF). The results were as follows; 1. CHT extract increased rCBF, but decreased BP, HR in a dose-dependent manner. 2. AF extract accelerated rCBF and movement of cardiacvascular system in a dose-dependent manner. 3. GR extract increased significantly rCBF(10.0mg/kg, p<0.05) as well as accelerated BP and rCBF in a dose-dependent manner. 4. CHTG extract increased significantly rCBF(10.0mg/kg, p<0.01) in a dose-dependent, but was not changed movement of cardiacvascular system. This results suggest that CHTG is significantly treated more than CHT in vertigo by wind, fire and phlegm.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.6
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• pp.587-595
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• 1999

This study was designed to investigate effects of calcium antagonists on endothelial and neuronal dysfunction of right coronary artery (RCA) induced by ischemia- reperfusion in anesthetized, open-chest pigs. After reperfusion, pigs were sacrificed and the RCA was rapidly dissected for in vitro experiments. Experimental groups were divided into 4 groups: control (C-RCA), ischemia-reperfusion only (I-RCA), verapamil infusion (VI-RCA) and nifedipine infusion (NI-RCA) group, respectively. The ischemia did not affect hemodynamics, mean arterial pressure, heart rate, LVdP/dtmax, and decreased RCA flow. Arterial pressure and heart rate during ischemia-reperfusion were decreased in VI-RCA and NI-RCA, and RCA flow during reperfusion was increased in NI-RCA. 5-Hydroxytryptamine (5-HT) produced concentration-dependent contractions in C-RCA. The 5-HT-induced contractions were potentiated in I-RCA and VI-RCA, but not in NI-RCA. Endothelium-dependent relaxation by calcium ionophore A23187 was inhibited in I-RCA and VI-RCA, and recovered in NI-RCA. Cyclic GMP contents were decreased in I-RCA group alone. Electrical field stimulation in C-RCA produced transient and frequency-dependent contractions and at 50 Hz caused biphasic contractions. The transient contractions were not affected by pretreatment with phentolamine and atropine, but the biphasic contraction was altered by the pretreatment. Both contractions were inhibited in I-RCA, and were partially recovered in VI-RCA and NI-RCA. Ischemia-reperfusion of RCA in pigs causes endothelial and neuronal dysfunctions, and calcium antagonists partially prevent both.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.5
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• pp.1191-1194
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• 2005

The aim of this study was to investigate the change of Heart Rate Variability(HRV) that mild cold stimulus on the forehead of healthy men induces. 34 healthy male subjects participated in the experiments. On the first test series, 15 subjects were applied to the mild cold stimulus by the devise for cold stimulation. In the second test series, 10 subjects With heat Syndrome and 5 subjects With cold Syndrome were applied to the mild cold Stimulus. Aa a additional test, 4 subjects with cold syndrome were applied to the warm stimulus in the last test series. We analyzed the HRV through measuring electrocardiogram.(ECG). The result of this study is comparatively clear. In the first test series, mild cold stimulus made parasympathetic nervous system be activated. In the second test series, mild cold stimulus made parasympathetic nervous system be activated both in subjects with heat syndrome and subjects with cold syndrome, and heat syndrome shows more active parasympathetic nervous system rather than cold syndrome subjects do. In the last test series, 2 subjects with cold syndrome respond the mild cold stimulus. That means warm stimulus of cold condition subjects made parasympathetic nervous system active in 2 of 4 subjects. We found out that mild cold stimulus on forehead makes parasympathetic nervous system be activated in healthy male, and it can be interpreted that mild cold stimulus make healthy human be relaxed. Also, subjects have different fondness of thermal stimulus according to their Cold or Heat condition Preferences. Last test series shows that we need to investigate effect of the warm stimulus heat syndrome subjects.

• The Korean Journal of Pain
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• v.12 no.1
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• pp.16-20
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• 1999

Background: Tourniquet pain has important impacts on anesthesia. Tourniquet pain and accompanying cardiovascular changes are important factors that make patients in distress during anesthesia. As tourniquet pain may be modified by anesthesia, a study on the changes in the neural functions by tourniquet inflation in normal volunteers is important. Methods: Time-dependent changes in tourniquet pain, heart rate, phantom limb sensation, motor function, pain to pressure on upper extremity of 10 healthy and unpremedied volunteers were measured. Each parameter were measured every 5 minutes starting from 10 minutes before inflation to 15 minutes after deflation of tourniquet. Tourniquet was deflated when the subject felt unbearable pain (score 100 with visual analog scale). Results: Subjects manifested time-dependent pain responses to tourniquet inflation, characterized by increase in VAS, systolic and diastolic blood pressure. Mean duration of tourniquet inflation was 36.4 minutes, volunteers experienced motor paralysis at 27.6 minutes and sensory loss at 33.1 minutes. Pain to pressure decreased over time in both arms. The degree of decrease was greater in the arm on which tourniquet was applied than that in the non-applied arm. Phantom limb sensation occurred in 3 subjects. Conclusions: This study demonstrated dynamic changes in the neural functions during tourniquet inflation period. Tourniquet-induced pain and resultant hypertension occurred in all subjects. Appropriate anesthetic management is needed for the surgery using tourniquet.

• Journal of Physiology & Pathology in Korean Medicine
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• v.26 no.4
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• pp.532-538
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• 2012

The aim of this study was to find correlation between EGG and HRV parameters in dyspeptic patients. 39 patients (male 8, female 31) were enrolled. EGG and HRV was measured in all patients. EGG parameters like % of gastric slow wave and power ratio were used to classify patients as normal or abnormal EGG groups. HRV parameters which were included TP (total power), LF(low frequency density), HF (high frequency density), and LF/HF ratio were compared between them. EGG parameters were compared among normal, sympathetic hyperactivity, and parasympathetic hyperactivity groups classified by LF/HF ratio. There was no difference in HRV parameters between normal and abnormal EGG groups. Comparing EGG parameters among normal, sympathetic hyperactivity, and parasympathetic hyperactivity groups, both sympathetic and parasympathetic hyperactivity groups had lower value of postprandial regularity of gastric slow wave than normal group. Abnormal value of LF/HF ratio(both sympathetic and parasympathetic hyperactivity) may be related with disturbance of electrical gastric activity in patients with dyspepsia.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.3
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• pp.287-295
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• 1998

Diazepam is known to have cardiovascular depressive effects through a combined action on benzodiazepinergic receptor and the GABA receptor-chloride ion channel complex. Moreover, it is known that barbiturates also have some cardiovascular regulatory effects mediated by the central GABAergic system. Therefore, this study was undertaken to delineate the regulatory actions and interactions of these systems by measuring the responses of the cardiovascular system and renal nerve activity to muscimol, diazepam and pentobarbital, administered intracerebroventricularly in rabbits. When muscimol $(0.03{\sim}0.3\;{\mu}\;g/kg)$, diazepam $(10{\sim}100\;{\mu}\;g/kg)$ and pentobarbital $(1{\sim}10\;{\mu}\;g/kg)$ were injected into the lateral ventricle of the rabbit brain, there were similar dose-dependent decreases in blood pressure (BP) and renal nerve activity (RNA). The relative potency of the three drugs in decreasing BP and RNA was muscimol ＞ pentobarbital ＞ diazepam. Muscimol and pentobarbital also decreased the heart rate in a dose-dependent manner; however, diazepam produced a trivial, dose-independent decrease in heart rate. Diazepam $(30\;{\mu}g/kg)$ augmented the effect of muscimol $(0.1\;{\mu}g/kg)$ in decreasing blood pressure and renal nerve activity, but pentobarbital $(3\;{\mu}g/kg)$ did not. Bicuculline $(0.5\;{\mu}g/kg)$, a GABAergic receptor blocker, significantly attenuated the effect of muscimol in decreasing BP and RNA, either alone or with diazepam, and that of pentobarbital in decreasing BP and RNA, either alone or with muscimol. We inferred that the central benzodiazepinergic and barbiturate systems help regulate peripheral cardiovascular function by modulating the GABAergic system, which adjusts the output of the vasomotor center and hence controls peripheral sympathetic tone. Benzodiazepines more readily modulate the GABAergic system than barbiturates.

• Journal of Life Science
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• v.18 no.3
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• pp.291-297
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• 2008

We investigated whether 1) the combined capsaicin (75 mg), sesamin (30 mg), and L-carnitine (900 mg) (CCSC) ingestion enhances autonomic nervous system (ANS) activities including thermogenic sympathetic activity as energy metabolic modulator, 2) ${\beta}_3-AR$ polymorphism of each subject influences with ANS activity. Seven healthy males $(22.0{\pm}0.5\;yr)$ volunteered for this study. The cardiac autonomic nervous activities evaluated by means of heart rate variability of power spectral analysis were continuously measured during 5 min every 30 min for total 120 min resting condition with CCSC or placebo oral administration chosen at random. The results indicated that, there are not $Arp/Arg^{64}$ variants of the ${\beta}_3-AR$ genotypes in our subjects. There were not also significant differences in heart rate during rest between both trials. The difference of ANS activity did not reach the statistical significance between both trials. However, the significant improvement showed TOTAL power, HF component, and the indices of SNS and PNS activities before and at 30 min after CCSC ingestion (p<0.05, respectively). In conclusions, although each component of combined CCSC is associated with lipolysis and/or fat oxidation, the combined CCSC consumption is not influenced in stimulation of thermogenic sympathetic activity as modulator of energy metabolism. In rather, our results suggested that CCSC ingestion improves the balance of both SNS and PNS activities. Therefore, it will be considered many combined nutrient components for ergogenic and/or lipolysis effects as well as genetic variants affecting ANS activity in further studies.