We compared the ventilatory and circulatory responses during 20 s of light dynamic leg and arm exercises performed separately using dominant and non-dominant limbs. Seventeen subjects performed a ...20-s single-leg knee extension-flexion exercise with a load of 5% of maximal muscle strength attached to the ankle. Fifteen of the seventeen subjects also did a single-arm elbow flexion-extension exercise in which a load was attached to the wrist in the same way as in the leg exercise. Similar movements were passively performed on the subjects by experimenters to avoid the effects of central command. The magnitude of change from rest (gain) in minute ventilation during passive movement (PAS) was significantly smaller in the dominant limbs than in the non-dominant limbs, though a significant difference was not detected during voluntary exercise (VOL). In contrast, heart rate and blood pressure responses did not show any differences between the dominant and non-dominant limbs during either VOL or PAS. In conclusion, the initial ventilatory response to PAS in the dominant limbs was lower than that of the non-dominant limbs, though the ventilatory response to VOL was not. Circulatory responses were not different between the dominant and non-dominant limbs. These results suggest that peripheral neural reflex during exercise could be different between dominant and non-dominant limbs and that ventilatory response at the onset of exercise might be controlled by the dual neural modulation of central command and peripheral neural reflex, resulting in the same ventilatory response to both dominant and non-dominant limb exercise.
We investigated the effects of a 3-day consecutive CO
-rich cold (20 °C) water immersion (CCWI) following a high-intensity intermittent test (HIIT) on subjects' sublingual temperature (T
), blood ...lactate (Lab), and heart rate (HR) compared to cold (20 °C) tap-water immersion (CWI) or passive recovery (PAS).
Thirty-two subjects were randomly allocated into three groups (CCWI, CWI, and PAS), each of which completed 4 consecutive days of cycling experiments. HR, T
, and Lab were recorded on each day of exercise testing (immersion from Day 1 to Day 3 and Day 4). HIIT consisted of 8 sets of 20-sec maximum exercise at an intensity of 120% of VO
max with 10-sec passive rest. The mean and peak power, and peak pedal repetitions (PPR) within HIIT were averaged and the decline in PPR (ΔPPR) from Day 1 to Day 4 was measured.
In CCWI and CWI, HR declined significantly following each immersion, with CCWI showing the larger reduction (p < 0.001). At Day 2, CCWI showed a significantly lower Lab compared to PAS (p < 0.01). The changes in mean and peak power from Day 1 to Day 4 did not differ among the groups (p = 0.302). ΔPPR of HIIT was significantly correlated with the HR and Lab values after immersions (ΔPPR-HR: r
= 0.938, p < 0.001, ΔPPR-Lab: r
= 0.999, p < 0.001).
These findings indicate that CCWI is a promising intervention for maintaining peak performance in high-intensity intermittent exercise, which is associated with a reduction in Lab and HR.
We examined the effect of the amount of eccentric exercise (ECC) on ventilatory response at the onset of exercise. The first 10 s of ventilatory response to exercise while using the leg that had ...performed a relatively greater number of ECC repetitions was greater than that of the leg that had done relatively fewer repetitions, suggesting that ventilatory response at the onset of exercise varies with the degree of change in muscle condition after ECC.
A specific kind of obesity that occurs in young women who appear thin but who have relatively greater percentage of body fat than is normal for their weight is called “masked obesity.” The definition ...of masked obesity is nutritionally and anthropometrically clear: body mass index (BMI) <25 kg/m2 and percentage of body fat (%BF) ≥30%. However, this definition allowed obesity to be underestimated. Thus, we determined that when mathematically analyzing the relationship between BMI and %BF, the equation %BF=aBMIb could be applied, where a (i.e., %BF/BMIb), converted by logarithmic function, is defined as an index for masked obesity (MOI). The MOI equation (a) was thus %BF/BMI2.12. We measured the height, weight, and %BF of 8,068 young women from all over Japan. The percentage of subjects with masked obesity above the defined criteria (BMI <25 kg/m2 and %BF ≥30%) was 7.4%. The mean MOI was 0.0444 in the masked obesity group and we determined additional cases of masked obesity if the MOI was greater than 0.0444. The percentage of additional masked obesity cases within the standard scale was 10.4%, and thus, the percentage of masked obesity was 17.8% in the young Japanese women tested.
We investigated the acute effects of cold-water immersion (20°C) with higher CO
concentration (CCWI) following a high-intensity Wingate anaerobic exercise test (WAnT) on subjects' sublingual ...temperature (T
), blood lactate (Lab), heart rate (HR), and aerobic cycling work efficiency (WE) compared to cold tap-water immersion (20°C; CWI) and passive recovery (PAS). Fifteen subjects completed three testing sessions at 1-week intervals. Each trial consisted of a first WE and WAnT, and a 20-min recovery intervention (randomized: CCWI, CWI, and PAS) before repeating a second WE and WAnT. The WE was measured by the metabolic demand during 50% V.O
max exercise. HR, T
, and Lab were recorded throughout the testing sessions. There was a significant decline in the WE from 1st bout to 2nd bout at each recovery intervention. The WAnT was also significantly reduced at 2nd bout. Significantly reduced Lab was achieved at CCWI compared to PAS, but not to the CWI. Likewise, the reduction in HR following immersion was the largest at CCWI compared to the other conditions. These findings indicate that CCWI is an effective intervention for maintaining repeated cycling work efficiency, which might be associated with reduced Lab and HR.
To examine the changes in heat shock proteins (HSPs) and calcineurin (CaN), a calcium/calmodulin regulated protein phosphatase, in hypertrophied rat skeletal muscles, adult male Wistar rats were ...administered clenbuterol (CLB, 30 mg l(-1) in drinking water), a beta 2-agonist, for 4 weeks. Compared to controls, CLB-treated rats had significantly larger body (10%) and relative (to body weight) soleus (Sol, 16%), plantaris (Plt, 32%) and gastrocnemius (Gast, 27%) weights. Immunohistochemically classified fast fibers were hypertrophied in the Sol (64%), Plt (62%), and deep (d, 70%) and superficial (s, 44%) regions of the Gast, whereas slow fibers were hypertrophied only in the Plt (47%). The percentage of fast fibers in the Sol increased from 10% to 21%. The myosin heavy chain (MHC) isoform composition shifted from slow to fast in the Sol (increase in the percentage of type IIa MHC and de novo synthesis of type IIx MHC) and Gast-d (de novo synthesis of type IIb MHC) and to the faster isoforms in the Plt (increase in the percentage of type IIb MHC). Hsp72 and Hsp90 levels in CLB-treated rats were 52% and 50% lower in the Sol and 44 and 41% lower in the Gast-d, respectively, than in control rats. In control rats, the relative content of CaN was: Sol>Gast-d>Plt>Gast-s, and CLB treatment enhanced the CaN content by 1.4-, 1.2-, 5.0-, and 3.3-fold, respectively. These results indicate that the down-regulation of HSPs in the Sol and Gast-d was closely related to a decrease in the slow phenotype, and that the relative up-regulation of CaN among the muscles/regions was closely related to the selective hypertrophy of fast fibers in the CLB-treated rats.
In this study we investigated the effects of hydrogen (H2) supplement, in the form of calcium bound H2 powder capsules, on aerobic and anaerobic cycling exercise.
Trained male subjects participated ...in a randomized, double-blind, crossover design trial and received H2-rich calcium powder (HCP) supplement (1500 mg/day, 2.544 μg/day of H2 gas) or H2-depleted placebo (PLA) (1500 mg/day) for 3 consecutive days.
Aerobic experiment: Eighteen subjects carried out a cycling incremental exercise starting at 20 watts (W) work rate, and increasing by 20 W/2 minutes until exhaustion. Blood gases including pH, bicarbonate ion (HCO3–), partial pressures of CO2 (PCO2), metabolic profile including lactate (Lac), and electrolytes including chloride (Cl–) were measured at rest and at 120-, 200-, and 240-W work rates.
Anaerobic experiment: Six subjects carried out a 30 second Wingate anaerobic exercise test (WAnT) bout with a resistive load of 7.5% of body mass. Lac was then measured at 1-, 3-, 5-, and 15-minutes following the WAnT exercise.
Aerobic experiment: At rest, HCP had a significantly lower pH (P = 0.048), Cl– (P = 0.011), and a higher HCO3– (P = 0.041), PCO2 (P = 0.026) compared to the PLA group. During exercise, pH decrease (supplement effect: P = 0.043) and the HCO3– increase (supplement effect: P = 0.030) continued in the HCP group. Additionally, HCP did not affect peak work load and exercise duration. And no changes were noted in Lac at rest or during exercise.
Anaerobic experiment: HCP did not affect peak power output or Lac recovery following WAnT. However the average power output during exercise was significantly higher in the HCP group (P = 0.019) compared to the PLA group.
HCP supplementation following 3 days of intake, slightly lowered pH during aerobic exercise, and increased average power output in the anaerobic WAnT exercise compared to the PLA group. HCP supplement might have an ergogenic effect in an anaerobic exercise setting.
This study was supported by The Japan Society for the Promotion of Science, and the Ministry of Education, Science, and Culture of Japan. In addition, we received a research grant from the company ENAGEGATE Inc. and they provided the HCP supplement and placebo. However, no intercession, restrictions or agreements of any kind was imposed between parties regarding research design, results or publications.
Abstract only
To examine the control of peripheral circulation to non‐active muscle and brain during leg cycling exercise, we measured the dynamics of brachial artery (BA) and middle cerebral artery ...(MCA) blood flow (BF) to sinusoidal (sine) work rate (WR) forcing. Nine healthy subjects performed upright leg cycle exercise with a constant WR for 30 min followed by 16‐min sine WR exercises of 4‐min period fluctuated between 20 W to 60% VO2max. During protocol, we measured pulmonary gas exchange breath‐by‐breath, heart rate (HR) and mean arterial blood pressure (MAP) Photoplethysmograph, blood velocity (BV) and cross sectional area of BA Ultrasound Pulsed‐Doppler, BV of MCA Transcranial Doppler Ultrasonograph, and forearm and forehead skin BF (SBF) Laser Doppler and sweating rate (SR) Capacitance Hygrometry. The variable was fitted as y(t)=M+A*sin((2π/T)*t‐θ), where t: time, A/M: relative amplitude, T: period, θ: phase shift. Almost variables traced the sine wave adequately. The phase of variables regarding O2‐transport such as VO2, HR followed sine WR with similar delays (the mean: VO2; 51, HR; 45 °). While the BV in MCA showed the similar phase (73 °), its A/M was small (4.5 %). Contrarily, the response of BA displayed an anti‐phase (175 °) and a large A/M (30 %). The peripheral circulatory responses to nonactive limb and brain is quite different. (Support: JSPS‐KAKENHI, 22370091, 23650390, 24700701, 24247046)
The Effects of Foot Baths on Energy Consumption NAKAMURA, Masatoshi; TOUDOH, Moe; EBINE, Naoyuki ...
The Journal of The Japanese Society of Balneology, Climatology and Physical Medicine,
2018/08/31, Volume:
81, Issue:
2
Journal Article
Open access
Foot baths reportedly reduce pain and improve sleeplessness. In addition, foot baths may induce vasodilation, and thereby improve blood flow, reduce swelling, induce relaxation, and increase deep ...body temperature. However, the influence of foot baths on energy metabolism and physiological indices are unclear. Therefore, the present study aimed to clarify the effects of foot baths on energy consumption and physiological indices (e.g., heart rate, tympanic temperature, and blood pressure). Nine healthy males were included in this study (age, 23.0±1.0 years; body weight, 66.5±5.6 kg; body fat percentage, 15.1±4.3%). Expired gas composition (i.e., oxygen and carbon dioxide consumption) was analyzed using the Food method in an environmentally-controlled room (room temperature 25°Cand humidity 40%). Subjects were rested in the hood during the measurement. After 30 min rest in the sitting position, a 30 min foot bath was performed, after which the subjects sat for 60 min. Expired gas composition and heart rate were measured over time, and tympanic temperature and blood pressure were measured every 15 min. The foot bath involved immersion of the knees, and the temperature of the water was maintained at 41°C. There were no significant changes in energy consumption after the foot bath, and no significant changes in heart rate, tympanic temperature, and blood pressure. Therefore, our results suggested that there were no significant energy metabolism changes after 30 min of foot bathing at 41°C.
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