Orally Administered Plasmalogens Alleviate Negative Mood States and Enhance Mental Concentration: A Randomized, Double-Blind, Placebo-Controlled Trial.

Background: Plasmalogens have been shown to improve neurodegenerative pathology and cognitive function. We hypothesized that plasmalogens work in small amounts as a kind of hormone interacting with a G protein-coupled receptor, and then explored the effects of scallop-derived purified plasmalogens on psychobehavioral conditions in a randomized placebo-controlled trial of college athletes in Japan. Methods and materials: Eligible participants were male students aged 18-22 years who belonged to university athletic clubs. They were randomly allocated to either plasmalogen (2 mg per day) or placebo treatment of 4 weeks' duration. The primary outcome was the T-score of the Profile of Mood States (POMS) 2-Adult Short, and the secondary outcomes included the seven individual scales of the POMS 2, other psychobehavioral measures, physical performance, and laboratory measurements. The trial was registered at the Japan Registry of Clinical Trials (jRCTs071190028). Results: Forty participants (20 in the plasmalogen group and 20 in the placebo group) completed the 4-week treatment. The Total Mood Disturbance (TMD) score of the plasmalogen group showed a greater decrease at 4 weeks than that of the placebo group while the between-group difference was marginally significant (p = 0.07). The anger-hostility and fatigue-inertia scores of the POMS 2 decreased significantly in the plasmalogen group, but not in the placebo group, at 4 weeks. Between-group differences in those scores were highly significant (p = 0.003 for anger-hostility and p = 0.005 for fatigue-inertia). The plasmalogen group showed a slight decrease in the Athens Insomnia Scale at 2 weeks, and the between-group difference was near-significant (p = 0.07). The elapsed time in minute patterns on the Uchida-Kraepelin test, which is a marker of mental concentration, revealed significantly greater performance in the plasmalogen group than in the placebo group. There were no between-group differences in physical and laboratory measurements. Conclusion: It is suggested that orally administered plasmalogens alleviate negative mood states and sleep problems, and also enhance mental concentration.

Ice ingestion with a long rest interval increases the endurance exercise capacity and reduces the core temperature in the heat.

BACKGROUND: The timing in which ice before exercise should be ingested plays an important role in optimizing its success. However, the effects of differences in the timing of ice ingestion before exercise on cycling capacity, and thermoregulation has not been studied. The aim of the present study was to assess the effect of length of time after ice ingestion on endurance exercise capacity in the heat. METHODS: Seven males ingested 1.25 g kg body mass-1 of ice (0.5 °C) or cold water (4 °C) every 5 min, six times. Under three separate conditions after ice or water ingestion ([1] taking 20 min rest after ice ingestion, [2] taking 5 min rest after ice ingestion, and [3] taking 5 min rest after cold water ingestion), seven physically active male cyclists exercised at 65% of their maximal oxygen uptake to exhaustion in the heat (35 °C, 30% relative humidity). RESULTS: Participants cycled significantly longer following both ice ingestion with a long rest interval (46.0 ± 7.7 min) and that with a short rest interval (38.7 ± 5.7 min) than cold water ingestion (32.3 ± 3.2 min; both p < 0.05), and the time to exhaustion was 16% (p < 0.05) longer for ice ingestion with a long rest interval than that with a short rest interval. Ice ingestion with a long rest interval (-0.55 ± 0.07 °C; both p < 0.05) allowed for a greater drop in the core temperature than both ice ingestion with a short rest interval (-0.36 ± 0.16 °C) and cold water ingestion (-0.11 ± 0.14 °C). Heat storage under condition of ice ingestion with a long rest interval during the pre-exercise period was significantly lower than that observed with a short rest interval (-4.98 ± 2.50 W m-2; p < 0.05) and cold water ingestion (2.86 ± 4.44 W m-2). CONCLUSIONS: Therefore, internal pre-cooling by ice ingestion with a long rest interval had the greatest benefit on exercise capacity in the heat, which is suggested to be driven by a reduced rectal temperature and heat storage before the start of exercise.

Comparison of the effects of cold water and ice ingestion on endurance cycling capacity in the heat.

PURPOSE: The purpose of this study was to examine the effects of pre-cooling and fluid replacement with either crushed ice or cold water. METHODS: On 2 separate occasions, in a counterbalanced order, 9 recreationally-trained males ingested 1.25 g/kg (80-100 g) of either crushed ice (0.5°C) or cold water (4°C) every 5 min for 30 min before exercise. They also ingested 2.0 g/kg (130-160 g) of the same treatment drink at 15 min, 30 min, and 45 min after the commencement of cycling to exhaustion at 60%VO2max until voluntary exhaustion in a hot environment (35°C and 30% relative humidity). RESULTS: The cycling time to exhaustion in the crushed ice trial (50.0 ± 12.2 min) was longer than the cold water trial (42.2 ± 10.1 min; p = 0.02). Although the rectal temperature fell by 0.37°C ± 0.03°C (p = 0.01) at the end of the resting period after the crushed ice ingestion, the rates of rise in rectal temperature during the exercise period were not significantly different between these 2 conditions (crushed ice: 0.23°C ± 0.07°C, 5 min; cold water: 0.22°C ± 0.07°C, 5 min; p = 0.94). CONCLUSION: Crushed ice ingestion before and during exercise in a hot environment may be a preferred and effective approach for minimizing thermal strain, and for improving endurance performance as compared with cold water ingestion.

Pre-cooling with intermittent ice ingestion lowers the core temperature in a hot environment as compared with the ingestion of a single bolus.

The timing in which ice is ingested may be important for optimizing its success. However, the effects of differences in the timing of ice ingestion has not been studied in resting participants. Therefore, the purpose of this study was to investigate the effects of differences in the timing of ice ingestion on rectal temperature (Tre) and rating of perceptual sensation in a hot environment. Seven males ingested 1.25gkg(-1) of crushed ice (ICE1.25: 0.5°C) or cold water (CON: 4°C) every 5min for 30min, or were given 7.5gkgBM(-1) of crushed ice (ICE7.5) to consume for 30min in a hot environment (35°C, 30% relative humidity). The participants then remained at rest for 1h. As physiological indices, Tre, body mass and urine specific gravity were measured. Rating of thermal sensation was measured at 5-min intervals throughout the experiment. ICE1.25 continued to decrease Tre until approximately 50min, and resulted in a greater reduction in Tre (-0.56±0.20°C) than ICE7.5 (-0.41±0.14°C). Tre was reduced from 40 to 75min by ICE1.25, which is a significant reduction in comparison to ICE7.5 (p<.05). Mean RTS with ICE1.25 at 50-65min was significantly lower than that with ICE7.5 (p<.05). These results suggest that pre-cooling with intermittent ice ingestion is a more effective strategy both for lowering the Tre and for the rating of thermal sensation.

Gait patterns and muscle activity in the lower extremities of elderly women during underwater treadmill walking against water flow.

This study sought to determine the characteristics of gait patterns and muscle activity in the lower extremities of elderly women during underwater treadmill walking against water flow. Eight female subjects (61.4+/-3.9 y) performed underwater and land treadmill walking at varying exercise intensities and velocities. During underwater walking (water level at the xiphoid process) using the Flowmill, which has a treadmill at the base of a water flume, the simultaneous belt and water flow velocities were set to 20, 30 and 4 m.min(-1). Land walking velocities were set to 40, 60 and 80 m.min(-1). Oxygen uptake and heart rate were measured during both walking exercises. Maximum and minimum knee joint angles, and mean angular velocities of knee extension and knee flexion in the swing phase were calculated using two-dimensional motion analysis. Electromyograms were recorded using bipolar surface electrodes for five muscles: the tibialis anterior (TA), medial gastrocnemius (MG), vastus medialis (VM), rectus femoris (RF) and biceps femoris (BF). At the same exercise intensity level, cadence was almost half that on land. Step length did not differ significantly because velocity was halved. Compared to land walking, the maximum and minimum knee joint angles were significantly smaller and the mean angular velocity of knee extension was significantly lower. Knee extension in the swing phase was limited by water resistance. While the muscle activity levels of TA, VM and BF were almost the same as during land walking, those of MG and RF were lower. At the same velocity, exercise intensity was significantly higher than during land walking, cadence was significantly lower, and step length significantly larger. The knee joint showed significantly smaller maximum and minimum angles, and the mean angular velocity of knee flexion was significantly larger. The muscle activity levels of TA, VM, and BF increased significantly in comparison with land walking, although those of MG and RF did not significantly differ. Given our findings, it appears that buoyancy, lower cadence, and a moving floor influenced the muscle activity level of MG and RF at the same exercise intensity level and at the same velocity. These results show promise of becoming the basic data of choice for underwater walking exercise prescription.

Relationship between cerebral activity and movement frequency of maximal finger tapping.

To examine the cerebral activity of the motor cortex during maximum movement, we measured regional cerebral blood flow (rCBF) in twelve normal volunteers, using near infrared spectroscopy (NIRS). Repetitive tapping of the right index finger was performed at 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, and 4.5 Hz, and during maximum effort (ME). The relative increase rate of rCBF during movement beginning with a resting condition was calculated for each movement condition. The left primary sensorimotor cortex showed significant activation during ME compared to the other frequencies. The rapid increase of rCBF was seen immediately after the initiation of finger tapping at all the tested frequencies but showed no increase following that. However, the rCBF during ME continued to increase until the end of the task. Change of the integrated electromyogram (iEMG) for the frequency and change of rCBF for the frequency at all the tested frequencies showed similar tendencies.

The prevalence of diabetes mellitus and impaired fasting glucose/glycaemia (IFG) in suburban and rural Nepal-the communities--based cross-sectional study during the democratic movements in 1990.

A rising prevalence of Type 2 diabetes and impaired fasting glucose/glycaemia (IFG) was recently reported in the urban areas of Nepal by Singh and Bhattarai [D.L. Singh, M.D. Bhattarai, High prevalence of diabetes and impaired fasting glycaemia in urban Nepal, Diabet. Med. 20 (2003) 170-171] in the first population-based study based on the revised diagnostic criteria of ADA-1997 and WHO-1998. In comparison with our community-based survey done in 1990 in suburban and rural areas of Nepal, the current data show a surprisingly rapid increase in the prevalence of diabetes in the Nepalese population. In our 1990 study, diabetes and IFG, respectively, were present in 1.4 and 2.5% of people > or =20 years old in suburban village (Bhadrakali) compared with 0.3 and 0.7% in a rural village (Kotyang). In a short communication, Singh and Bhattarai found the rates to be 14.6 and 9.1% in urban areas, and 2.5 and 1.3% in rural areas. This phenomena appears to have been influenced more by rapid urbanization and changes in lifestyles after the ongoing democratic movements that have taken place since 1990 in Nepal. Moreover, our new analysis of the data provide baseline features for the planning of health care policy and establishment of medical priorities in modern day Nepal.

The effect of maximal finger tapping on cerebral activation.

The purpose of the present study was to investigate the effect of the repetition rate of a simple movement on the magnitude of neuronal recruitment at maximal effort in humans. Nine right-handed healthy subjects [age: 27.4 +/- 4.8 yr, stature: 174.5 +/- 12.2 cm, body-weight 74.3 +/- 16.6 kg (Mean +/- SD)] participated in this study. We measured the regional cerebral hemodynamics using 24-channel near infrared spectroscopy (NIRS). An auditory-cued, repetitive flexion movement of the right index finger against a button was performed as the finger-tapping task at maximal effort (ME), at 25% of maximal effort (25% ME) and at 50% of maximal effort (50% ME). The increase of the left primary motor cortex hemodynamics during movement relative to the hemodynamics under the resting condition was calculated for each pair of movement conditions. The frequency of finger-tapping was 1.61 +/- 0.18 Hz (25% ME trial), 3.23 +/- 0.36 Hz (50% ME trial), and 6.46 +/- 0.72 Hz (ME trial). The left primary motor cortex showed significant activation under all conditions. The change in total hemoglobin ([tHb]) between the ME trial and the resting value (1.19 +/- 0.93 mmol.mm) was significantly higher than those between the resting value and the 25% ME trial (0.04 +/- 0.04 mmol.mm) or the 50% ME trial (0.08 +/- 0.11 mmol x mm) (p < 0.05). There was a 29.8-fold increase of the [tHb] value between the 50% ME trial and the ME trial, but only a 2-fold increase of the [tHb] value between the 25% ME trial and the 50% ME trial. These results demonstrated that the rate of change in regional cerebral hemoglobin at a maximal effort finger-tapping task was much higher than that at a low frequency finger-tapping task.

Cerebral oxygenation during intermittent supramaximal exercise.

This study examined cerebral deoxygenation during intermittent supramaximal exercise in six healthy male subjects (age: 27.2 +/- 0.6 years (mean +/- S.E.). The subjects performed seven times exercise at an intensity corresponding to 150% of maximal oxygen uptake (VO2max) on cycle ergometer (30 s exercise/15 s rest). Cerebral oxygenation was measured by near-infrared spectroscopy (NIRS). The peak blood lactate concentration after exercise was 15.3 +/- 0.2 mmol/l. Cerebral oxygenation increased in first repetition compared with at rest (+ 5.7 +/- 0.6 microM; P < 0.05), but then decreased with time. Thus, in the last repetition cerebral oxygenation was - 8.5 +/- 0.4 microM (P < 0.05). There was no significant change in arterial oxygen saturation (99.6 +/- at rest, 98.4 +/- 0.2 at the final set of intermittent exercise), and there was no correlated change in end-tidal CO2 concentration with cerebral oxygenation (P > 0.05). These findings suggest that the fatigue resulting from dynamic severe exercise related to a decrease in the cerebral oxygenation level.

Muscle oxygenation kinetics at the onset of exercise do not depend on exercise intensity.

The purpose of this study was to determine whether the onset kinetics of muscle oxygenation in localized working muscle (mOxy) was affected by differences in exercise intensity. Five healthy male subjects exercised for 6 min at 125 W, 150 W, and 175 W, and 1 min at 300 W on a cycle ergometer. mOxy was estimated by near-infrared spectroscopy (NIRS) with a continuous wave photometer. The NIRS probe was positioned on the vastus lateralis muscle of the right leg. The relative change in mOxy was calculated from the relative change of the oxygenated hemoglobin (OxyHb) and deoxygenated hemoglobin (DeoxyHb) concentration from their resting values ([mOxy]=Delta[OxyHb]-Delta[DeoxyHb]). Assuming an exponential time course with time delay, the time constants of the mOxy were 5.7 (SD 2.2) s at 125 W, 5.6 (SD 1.9) s at 150 W, 6.0 (SD 2.2) s at 175 W, and 5.6 (SD 2.1) s at 300 W. The time delays of the mOxy were 6.7 (SD 4.2) s at 125 W, 8.6 (SD 1.6) s at 150 W, 6.4 (SD 3.0) s at 175 W, and 5.4 (SD 2.9) s at 300 W. The mean response times of the mOxy were 12.5 (SD 2.7) s at 125 W, 14.2 (SD 2.4) s at 150 W, 12.4 (SD 4.4) s at 175 W, and 11.0 (SD 3.1) s at 300 W. These results indicate that the kinetics of mOxy were not affected by differences in exercise intensity.

Does the regional oxygen uptake measured by near infrared spectroscopy reflect the phase II pulmonary oxygen uptake at the onset of exercise?

It has been hypothesized that the signals of near infrared spectroscopy (NIRS) would reflect muscle O(2) uptake (mVO(2)). Although it is not definite that NIRS signals accurately reflect mVO(2), there is every possibility that NIRS signals at least reflect regional O(2) uptake (rVO(2)). The phase II kinetics of pulmonary oxygen uptake (pVO(2)) is regarded as reflecting mVO(2) at the onset of exercise. To examine whether the rVO(2) on-kinetics measured by NIRS reflects the mVO(2) on-kinetics at the onset of exercise, we compared the rVO(2) as measured by NIRS with the phase II kinetics of pVO(2) at the onset of exercise. Twelve healthy male subjects cycled a Monark ergometer at three different intensities: below the ventilatory threshold (VT) level (below-VT), on the VT level (on-VT), and above the VT level (above-VT), for 6 minutes on three separate occasions. The rVO(2) was calculated from the concentration of oxyhemoglobin and deoxyhemoglobin, as measured by NIRS every 3 seconds. The pVO(2) was determined by the breath-by-breath method. A significant relationship between the amount of increases of pVO(2) and rVO(2) from rest to the end of exercise among all levels of exercise intensity was found (r=0.935, P<0.001). The time constants of rVO(2) (rVO(2)-Tc: below-VT: 6.514+/-2.159 s, on-VT: 7.760+/-2.035 s, above-VT: 9.532+/-2.342 s) were significantly faster than the time constants of pVO(2) (pVO(2)-Tc: below-VT: 23.8+/-4.4 s, on-VT: 25.9+/-5.1 s, above-VT: 26.3+/-5.7 s) (P<0.001). There was no significant relationship between rVO(2)-Tc and pVO(2)-Tc for each intensity (P>0.05). We conclude that the rVO(2) on-kinetics measured by NIRS does not necessarily reflect the mVO(2) kinetics at the onset of exercise.