• Journal of Life Science
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• v.21 no.1
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• pp.9-14
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• 2011

Perceived exertion involves detection and interpretation of sensations arising from the body during physical exercise. Physiological variables such as heart rate and oxygen consumption positively correlate with ratings of perceived exertion (RPE). It is unknown whether the accuracy of predicting exercise intensity from RPE differs between men and women. Therefore, it was examined whether men or women could predict relative exercise intensity, determined by oxygen consumption, more accurately from RPE. Ten male and ten female young adult subjects aged 25.1${\pm}$3.52 yr volunteered to participate. RPE were determined by the Borg 15-category scale, and a standard Bruce treadmill protocol was used to perform graded exercise testing. There was no significant difference in slope means between males and females (p=0.501). No significant difference was observed when plotting rates of perceived exertion (RPE) vs. percentage of $VO_2$ max. The relative maximal oxygen consumptions ($VO_{2max,\;}_{rel}$) were 52.36${\pm}$7.35 ml/kg/min for males and 41.44${\pm}$6.71 ml/kg/min for females, respectively and there was a significantly high difference between the two groups in the relative $VO_{2max}$, as well as figures of 4.05${\pm}$0.36 l/min for males and 2.53${\pm}$0.39 l/min for females in the absolute $VO_{2max}$ in this study. There were no significant differences in slope, y-intercept, and standard error of estimate (SEE) between males and females. No significant difference with RPE according to exercise intensity was found between males and females. However, RPE was a useful predictor of exercise intensity in independent genders.

• Journal of Environmental Science International
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• v.16 no.1
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• pp.55-63
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• 2007

There are concerns that chemical residues could harm the consumer on the environment, although 50 to 80% of the crops would be destroyed by pests and others without agrochemicals. Environmental fate and ecotoxicity studies are usually carried out to assess the impact on the human and the environment. A comparision of the Daphnia magnia and Simocephalus mixtus toxicity was performed to study the relative sensitivities and discrimination abilities to agriculture chemicals. The species of Simocephalus mixtus was more sensitive to agriculture chemicals than Daphnia magnia. Simocephalus mixtus was approved to be a water flea in determining insecticide and pesticide toxicity by heart-beat rate in a consistency and repeatability. The order of acute toxicity to water flea Daphnia magnia for ecotoxicity test was carbaryl>benomyl>amtirole with both Daphnia magnia and Simocephalus mixtus. The heartbeat pattern after the exposure to agrochemicals was different from that of exposure to heavy metals. Agrochemical leathal concentration test with heartbeat rate measurement was found to be more appropriate than inhibition concentration test with respect to toxicological endpoint.

• Journal of Korean Society of Forest Science
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• v.113 no.1
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• pp.107-117
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• 2024

This study investigated temporal changes in forest physical variables and their effects on thermal comfort and physiological and psychological responses. Environmental factors (air temperature, mean radiant temperature, wind speed, and relative humidity), the predicted mean vote (PMV), and the predicted percentage of dissatisfied (PPD) visitors were continuously measured between 9:00 AM and 6:00 PM. We assessed the physiological and psychological responses (heart rate variability, heart rate, oral temperature, blood pressure, pulse rate, thermal sensation vote, comfort sensation vote, and subjective feelings) of 30 male university students (average age: 21.7±1.9 years), who closed their eyes and relaxed for 5 minutes every hour. Examination of correlations between environmental factors and physiological responses showed that ① the mean radiant temperature, wind speed, and relative humidity significantly changed with time; ② PMV and PPD also showed significant changes over time, and the thermal sensation vote corresponded with PMV; however, the comfort sensation vote did not correspond with PPD; ③ Among the physiological responses, parasympathetic nerve activity, sympathetic nerve activity, heart rate, and diastolic blood pressure significantly varied with time, with parasympathetic nerve activity having the lowest value and sympathetic nerve activity the highest at the highest air temperature (2:00-4:00 PM); and ④ Air temperature, mean radiant temperature, and wind speed showed a negative correlation with parasympathetic nerve activity and a positive correlation with sympathetic nerve activity. These findings indicate that the relaxation effects of the forest environment depend on what time of day people are exposed to it, and the changes occurring in forest environmental factors over time modulate these effects.

• 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.

• Fashion & Textile Research Journal
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• v.7 no.3
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• pp.309-314
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• 2005

This study was to determine whether the massage would enhance the physical relaxation in healthy women, and whether the effects of massage on the relaxation would be different by the applied regions of the body. Five healthy young women participated in the two test sessions of back and lower extremities massage in a chamber controlled at an air temperature of $28^{\circ}C$ and a relative humidity of $50{\pm}5%$. The slow stroke massage with lavender aroma oil for 30 minutes was applied to the subjects with a 10-min. and a 20-min rest time before and after the application, respectively. Rectal temperature decreased and the chest and thigh skin temperatures increased with the massage application, and the changes of the temperatures were greater with lower extremities massage than with back massage. Heart rate also decreased during massage period and tended to be lower with lower extremities massage. Systolic and diastolic blood pressure decreased with lower extremities massage. These results show that the slow stroke massage for 30 minutes can induce physiological responses related with the enhanced relaxation in healthy women, and lower extremities massage is more effective on the physical relaxation rather than back massage.

• 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.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2000.04a
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• pp.62-66
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• 2000

This study investigated the effects of certain specific wavelengths of lighting on the autonomic nervous system (ANS) using the heart rate variability (HRV) as an index. Six subjects with normal color vision participated n this study between 15:00 and 17:00 hr to neutralize any visual differences arising from circadian rhythm. The environmental conditions of the laboratory were maintained in complete darkness and the temperature was equilibrated at 24$\Box$ with a relative humidity of 60%. Subjects were only subjected to light stimulation when the pupil of dyes attained a minimum size of 2 mm by projecting illumination equalized with the same spectral radiance of 500-700 nm with 50-nm internal radiance. HRV was calculated from electrocardiogram (ECG) with systematic respiratory control at 0.35 Hz. The results suggest that illumination with certain wavelengths may induce ANS activation.

• Journal of the Korean Home Economics Association
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• v.39 no.5
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• pp.39-47
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• 2001

The purpose of this study was to investigate two different kinds of t-shirts on thermal responses at air temperature of $23{\pm}2^{\circ}C$, relative humidity of $70{\pm}5%$ and wind velocity not more than 0.5 m/sec. Five healthy men wearing boxy type t-shirts or fitted type t-shirts, participated as the subjects. Rectal temperature, skin temperatures, heart rate, clothing microclimate and subjective sensation were measured every 2 minute during experiment(rest, walking, recovery each 20 min.) and compared between two experimental garments(boxy type and fitted type t-shirts). Rectal temperature was lower in recovery phase at wearing fitted type t-shirts. Chest skin temperature was higher at wearing fitted type t-shirts and thigh and leg skin temperature were higher at wearing boxy type t-shirts.

• Korean Journal of Clinical Pharmacy
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• v.16 no.2
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• pp.113-122
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• 2006

Purpose: A retrospective study was performed to assess the efficacy and tolerance of ${\beta}-blocker$ administration in patients with heart failure and diabetes. Method: Records of 164 patients who were treated for the heart failure condition more than a year were studied retrospectively. Patients were divided into 4 groups based on their diabetes(DM) status and the administration of ${\beta}-blockers$ ($DM+{\beta}-blocker$ group: 14, DM w/o ${\beta}-blocker$: 19, No DM + ${\beta}-blocker$: 62, No DM + no ${\beta}-blocker$: 69). All patients had been receiving conventional therapy such as digoxin, ACE-I, ARB, diuretics, nitrates, aspirin, anticoagulants or lipid-lowering agents. The primary endpoints (death and hospital admission) were recorded during 1 year period and hemodynamic factors (HR, LVEF, SBP, DBP) were obtained from all patient groups before and after 12 months of ${\beta}-blocker$ treatment. To evaluate toxicity of ${\beta}-blocker$, SCr, BUN, AST, ALT and Alkaline phosphatase were obtained. Result: There were less death and hospital admission in DM + ${\beta}-blocker$ group than in DM without ${\beta}-blocker$ group (p=0.014). Relative risk of hospital admission for $DM+{\beta}-blocker$ group over no DM group was 1.17. Long term ${\beta}-blocker$ administration was associated with an improvement of heart rate in patients with DM (P< 0.02) with no significant improvement of LVEF, SBP, DBP. in DM patient. In patient without DM, ${\beta}-blocker$ was associated with improvement in LVEF, HR and DBP (P<0.01, P<0.03), but not in SBP. The incidence of toxicity was similar between the four group with no significant difference. Conculsion: Treatment of heart failure patients with ${\beta}-blocker$ appears to be beneficial in terms of hospital admission event and several hemodynamic factors. The toxicities of ${\beta}-blocker$ treatment were not significant and the treatment is generally well-tolerated in most of the heart failure patients.

• The Korean Journal of Physiology and Pharmacology
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• v.28 no.3
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• pp.209-217
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• 2024

In addition to cellular damage, ischemia-reperfusion (IR) injury induces substantial damage to the mitochondria and endoplasmic reticulum. In this study, we sought to determine whether impaired mitochondrial function owing to IR could be restored by transplanting mitochondria into the heart under ex vivo IR states. Additionally, we aimed to provide preliminary results to inform therapeutic options for ischemic heart disease (IHD). Healthy mitochondria isolated from autologous gluteus maximus muscle were transplanted into the hearts of Sprague-Dawley rats damaged by IR using the Langendorff system, and the heart rate and oxygen consumption capacity of the mitochondria were measured to confirm whether heart function was restored. In addition, relative expression levels were measured to identify the genes related to IR injury. Mitochondrial oxygen consumption capacity was found to be lower in the IR group than in the group that underwent mitochondrial transplantation after IR injury (p < 0.05), and the control group showed a tendency toward increased oxygen consumption capacity compared with the IR group. Among the genes related to fatty acid metabolism, Cpt1b (p < 0.05) and Fads1 (p < 0.01) showed significant expression in the following order: IR group, IR + transplantation group, and control group. These results suggest that mitochondrial transplantation protects the heart from IR damage and may be feasible as a therapeutic option for IHD.