The aim of this study was to investigate the effects of vegetable tablets containing Gamma-Aminobutyric Acid (GABA) intake on cardiovascular response and the autonomic nervous system in young adults. In a double-blind, randomized controlled trial, 7 healthy subjects were assigned to take vegetable tablets (10 g/trial) or control tablets (10 g/trial). We measured heart rate (HR), systolic and diastolic blood pressure, stroke volume, cardiac output, total peripheral resistance index, and the low- and high-frequency oscillatory components of heart rate variability (HRV). Two major spectral components were examined at low-frequency (LF: 0.04–0.15 Hz) and high-frequency (HF: 0.15–0.4 Hz) bands to indicate HRV. There were significant interactions in HR (p<0.01) and in LF/HF of HRV (p<0.05). HR increased after intake of control tablets, but not after that of vegetable tablets. LF/HF increased rapidly after intake of control tablets and rose slightly after vegetable tablet intake. There was no significant difference between the vegetable and control tablet trials in stroke volume, cardiac output, total peripheral resistance, systolic or diastolic blood pressure, HF, or LF. In conclusion, these results suggest the possibility that single administration of vegetable tablets containing GABA suppresses the sympathetic nervous activity leading to an elevation of blood pressure.

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This study aimed to examine the relationships between force and subjective muscle-fatigue sensation (SMS), and muscle oxygenation kinetics during sustained static gripping using a progressive workload. Subjects consisted of 10 males (height 173.2±7.1 cm, body weight 70.3±15.1 kg, and age 21.1±1.5 years). They performed sustained static gripping with 7 gradually increasing relative demand values of 20% to 80% maximal voluntary contraction (MVC). The staging of the progressive workload was 10 s for 20% MVC, 20 s each for 30, 40, 50, 60, and 70% MVC, and 10 s for 80% MVC. Borg's SMS was used to measure the fatigue sensation of the antebrachial region in a pre-test and every 10 s during the test. The time to reach minimum Oxy-Hb/Mb appeared at about 50 s (52.6±25.2 s) after the onset of sustained static gripping, and the time to reach maximum Deoxy-Hb/Mb occurred later at 90 s. Significant and high correlations (r=0.632–0.721) were found between the time to reach maximum Deoxy-Hb/Mb, and Peak Force Time and Average Force. Even though the demand values caused a workload increase and reached 50% MVC, the change of Total Hb/Mb and Oxy-Hb/Mb kinetics was relatively small. Therefore, the effect caused by an obstruction of blood volume may not occur during the progressive workload. It was determined that the contraction time after the peak of SMS is relatively short and an individual difference in force value expands in the phase where SMS reaches its peak.

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The aim of the present study was to investigate the effects of home-based exercise without home visits on physical function, falls, and bone mineral density in community-dwelling elderly women. Sixty community-dwelling, elderly (≥65 years of age) women were recruited from a Japanese community. Subjects were randomly assigned to a home-based exercise group or a control group. The subjects assigned to the home-based exercise group performed home-based exercise without home visits 3 times per week for 6 months in their homes. Assessments of physical function and bone mineral density were carried out before and after intervention in both groups. Muscle strength, gait velocity, the timed up and go test (TUGT), single leg stance time, the bend reach performance test, and reaction time were measured to assess physical function. The patients' history of falls was also assessed before and after the 12-month follow-up. To determine bone mineral density, the speed of sound (SOS) at the right calcaneus was measured using a quantitative ultrasound device. There were no significant differences between the two groups in baseline characteristics. 82.6% of subjects completed the prescribed exercise program in the home-based exercise group. Compared to the control group, TUGT improved significantly (p<0.05) in the home-based exercise group. Home-based exercise without home visits can be adopted for community-dwelling elderly women, particularly since no specific place or instructor is needed.

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The present study examined whether a sit-to-stand score can be related to the force-generating capacity of knee extensor muscles. Fifty-seven subjects (28 men, 63.0±7.8 yrs, and 29 women, 64.2±7.5 yrs, means±SDs) performed a 10-repeated sit-to-stand test as fast as possible, on a steel molded chair. The time taken (T_sit-stand) was measured with a manual stopwatch. The leg length (L), defined as the distance from the great trochanter of the femur to the malleolus lateralis, was measured using a tape. A power index of the test (P_sit-stand) was calculated by using the following equation: P_sit-stand=(L−0.4)×body mass×g×10/T_sit-stand. The cross-sectional area of the quadriceps femoris muscle (CSA_KE) and the maximal voluntary isometric knee extension force (F_KE) were measured using MRI and a static myometer, respectively. There was no significant correlation between T_sit-stand and each of CSA_KE and F_KE. On the other hand, the P_sit-stand was highly correlated with CSA_KE and F_KE, even after the influence of body mass and L was statistically eliminated. These results indicate that P_sit-stand, derived from three variables of body mass, leg length, and time taken for a sit-to-stand test, can be a useful index to assess the force-generating capacity of the knee extensor muscles of elderly individuals.

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The aim of this study was to examine the relationship between menses-associated health problems of women, such as premenstrual symptoms, menstrual pain and irregular menstrual cycles, and psychosocial stress. A cross-sectional study was conducted among Japanese college students, measuring psychosocial stress levels by means of IMPS (The Inventory to Measure Psychosocial Stress). A total of 264 female students (mean age 19.4 years), who were invited to participate in the study in October 2007, completed the questionnaire, which dealt with anthropometric data, lifestyle, menstrual history, and menstrual health status. Forty-three students were excluded due to missing data, and the remaining 221 were analyzed. The proportions of students who reported premenstrual symptoms, menstrual pain, and the experience of irregular menstrual cycles were 79%, 79%, and 63%, respectively. Students who reported premenstrual symptoms, menstrual pain, and the experience of irregular menstrual cycles had higher stress scores than those who did not. Multiple logistic regression analyses were used to identify independent factors associated with having premenstrual symptoms, menstrual pain, and the experience of irregular menstrual cycles. Stress score, heavy menstrual flow, and menstrual pain were significant predictors for premenstrual symptoms, while age at menarche and having premenstrual symptoms were significant predictors for menstrual pain. Both stress score and body mass index were found to be significant predictors for having experienced irregular menstrual cycles. The results suggest that psychosocial stress is independently associated with premenstrual symptoms and the experience of irregular menstrual cycles among college students, implying that changes in the functional potentiality of women as a result of stress are related with changes in their menstrual function.

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The cutaneous vasodilation and sweating responses of prepubertal children to heat stress were examined. Seven prepubertal boys (9–11 years old) and 9 young men (20–24 years old) were seated wearing only swimming trunks while the air temperature (T_a) was linearly increased from 28°C to 40°C over 50 min and then maintained at 40°C for an additional 10 min. Skin temperature, cutaneous vascular conductance (CVC), and local sweating rate (m_sw) were measured at multiple sites on the body. The boys had a significantly greater mean surface area-to-mass ratio compared with the young men. The rectal temperature did not change in either group with increasing T_a, although it was significantly higher in the boys. During the first half of the exposure period, when T_a was less than the mean skin temperature (T_sk), the boys had significantly higher CVC on the chest and significantly lower m_sw on the chest and thigh as compared with the young men. During the latter half of the exposure, when heat stress was increased as T_a exceeded T_sk, the boys had significantly higher T_sk, greater CVC on the chest and finger, greater rate of increase in the CVC on the forehead and finger, lower m_sw on the chest and thigh, greater increase in heart rate, and higher thermal sensation. The mean body temperature at the onset of sweating was significantly greater in the boys than in the men. These results suggest that, compared with young men, prepubertal boys manifest greater physiological and perceptual strain under heat stress induced by T_a exceeding T_sk, which is most probably attributable to a combination of lower evaporative heat loss, as evidenced by lower m_sw, and greater heat gain owing to a larger surface area-to-mass ratio. The maturation-related differences in heat loss responses vary according to body site.

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A technique for measuring the psychophysiological status of the human and associated applications based on normal brain signals are examined and evaluated. A small single-point dry electrode developed for mobile use can capture brainwave activity from among dense external and internal electrical noise, and subsequently extract targeted frequency components. Continuous measurements during day and night provide a brainwave profile including wake and sleep states that can consistently explain states of human awareness. Statistical evaluation provides psychophysiological state change patterns which can be used to distinguish levels of alertness so as to prevent or avoid hazardous situations. We have taken a typical daily activity, namely, driving a car, to examine the applicability of our proposed method. Test results in terms of brain wave state show that the pattern while driving is changed by specific activity such as when talking on a mobile phone.

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