Prior Heavy-Intensity Exercise's Enhancement of Oxygen-Uptake Kinetics and Short-Term High-Intensity Exercise Performance Independent of Aerobic-Training Status

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Adaptation and penetration of resin-based root canal sealers in root canals irradiated with high-intensity lasers

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Differences in acoustic and perceptual parameters of the voice between elderly and young women at habitual and high intensity

The present study aimed to compare elderly and young female voices in habitual and high intensity. The effect of increased intensity on the acoustic and perceptual parameters was assessed. Sound pressure level, fundamental frequency, jitter, shimmer, and harmonic to noise ratio were obtained at habitual and high intensity voice in a group of 30 elderly women and 30 young women. Perceptual assessment was also performed. Both groups demonstrated an increase in sound pressure level and fundamental frequency from habitual voice to high intensity voice. No differences were found between groups in any acoustic variables on samples recorded with habitual intensity level. No significant differences between groups were found in habitual intensity level for pitch, hoarseness, roughness, and breathiness. Asthenia and instability obtained significant higher values in elderly than young participants, whereas, the elderly demonstrated lower values for perceived tension and loudness than young subjects. Acoustic and perceptual measures do not demonstrate evident differences between elderly and young speakers in habitual intensity level. The parameters analyzed may lack the sensitivity necessary to detect differences in subjects with normal voices. Phonation with high intensity highlights differences between groups, especially in perceptual parameters. Therefore, high intensity should be included to compare elderly and young voice.

High-intensity resistance training attenuates dexamethasone-induced muscle atrophy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

High-intensity interval training and hypertension: Maximizing the benefits of exercise?

Essential arterial hypertension is the most common risk factor for cardiovascular morbidity and mortality. Regular exercise is a well-established intervention for the prevention and treatment of hypertension. Continuous moderate-intensity exercise training (CMT) that can be sustained for 30 min or more has been traditionally recommended for hypertension prevention and treatment. On the other hand, several studies have shown that high-intensity interval training (HIT), which consists of several bouts of high-intensity exercise (~85% to 95% of HRMAX and/or VO2MAX lasting 1 to 4 min interspersed with intervals of rest or active recovery, is superior to CMT for improving cardiorespiratory fitness, endothelial function and its markers, insulin sensitivity, markers of sympathetic activity and arterial stiffness in hypertensive and normotensive at high familial risk for hypertension subjects. This compelling evidence suggesting larger beneficial effects of HIT for several factors involved in the pathophysiology of hypertension raises the hypothesis that HIT may be more effective for preventing and controlling hypertension.

The effects of high-intensity resistance exercise on the blood lipid profile and liver function in hypercholesterolemic hamsters

It is well established that atherogenic dyslipidemia, characterized by high levels of triglycerides (TG), total cholesterol (TC), and low-density lipoprotein (LDL) cholesterol and low levels of high-density lipoprotein (HDL) cholesterol, constitutes important risk factors for cardiovascular disease. Regular exercise has been associated with a reduced risk for metabolic diseases. However, studies supporting the concept that resistance exercise is a modifier of blood lipid parameters are often contradictory. The aim of this study was to investigate the effects of high-intensity resistance exercise on the serum levels of TG, TC, HDL and non-HDL cholesterol, glucose, and the liver function enzymes alanine aminotransferase (ALT, EC 2.6.1.2) and aspartate aminotransferase (AST, EC 2.6.1.1) in golden Syrian hamsters (Mesocricetus auratus (Waterhouse, 1839)) fed a hypercholesterolemic diet. Sedentary groups (S) and exercise groups (E) were fed a standard diet (SS and ES) or a cholesterol-enriched diet (standard plus 1% cholesterol, SC and EC). Resistance exercise was performed by jumps in the water, carrying a load strapped to the chest, representing 10 maximum repetitions (10 RM, 30 s rest, five days per week for five weeks). Mean blood sample comparisons were made by ANOVA + Tukey or ANOVA + Kruskal-Wallis tests (p < 0.05) to compare parametric and nonparametric samples, respectively. There were no differences in blood lipids between the standard diet groups (SS and ES) (p > 0.05). However, the EC group increased the glucose, non-HDL, and TC levels in comparison with the ES group. Moreover, the EC group increased the TG levels versus the SC group (p < 0.05). In addition, the ALT levels were increased only by diet treatment. These findings indicated that high-intensity resistance exercise contributed to dyslipidemia in hamsters fed a hypercholesterolemic diet, whereas liver function enzymes did not differ in regards to the exercise protocol.

Similar health benefits of endurance and high-intensity interval training in obese children

Purpose: To compare two modalities of exercise training (i.e., Endurance Training [ET] and High-Intensity Interval Training [HIT]) on health-related parameters in obese children aged between 8 and 12 years. Methods: Thirty obese children were randomly allocated into either the ET or HIT group. The ET group performed a 30 to 60-minute continuous exercise at 80% of the peak heart rate (HR). The HIT group training performed 3 to 6 sets of 60-s sprint at 100% of the peak velocity interspersed by a 3-min active recovery period at 50% of the exercise velocity. HIT sessions last similar to 70% less than ET sessions. At baseline and after 12 weeks of intervention, aerobic fitness, body composition and metabolic parameters were assessed. Results: Both the absolute (ET: 26.0%; HIT: 19.0%) and the relative VO2 peak (ET: 13.1%; HIT: 14.6%) were significantly increased in both groups after the intervention. Additionally, the total time of exercise (ET: 19.5%; HIT: 16.4%) and the peak velocity during the maximal graded cardiorespiratory test (ET: 16.9%; HIT: 13.4%) were significantly improved across interventions. Insulinemia (ET: 29.4%; HIT: 30.5%) and HOMA-index (ET: 42.8%; HIT: 37.0%) were significantly lower for both groups at POST when compared to PRE. Body mass was significantly reduced in the HIT (2.6%), but not in the ET group (1.2%). A significant reduction in BMI was observed for both groups after the intervention (ET: 3.0%; HIT: 5.0%). The responsiveness analysis revealed a very similar pattern of the most responsive variables among groups. Conclusion: HIT and ET were equally effective in improving important health related parameters in obese youth.

Temperature changes on the root surfaces of mandibular incisors after an 810-nm high-intensity intracanal diode laser irradiation

Temperature changes caused by laser irradiation can promote damage to the surrounding dental tissues. In this study, we evaluated the temperature changes of recently extracted human mandibular incisors during intracanal irradiation with an 810-nm diode laser at different settings. Fifty mandibular incisors were enlarged up to an apical size of ISO No. 40 file. After the final rinse with 17% ethylenediaminetetraacetic acid, 0.2% lauryl sodium sulfate biologic detergent, and sterile water, samples were irradiated with circular movements from apex to crown through five different settings of output power (1.5, 2.0, 2.5, 3.0, and 3.5 W) in continuous mode. The temperature changes were measured on both sides of the apical and middle root thirds using two thermopar devices. A temperature increase of 7 degrees C was considered acceptable as a safe threshold when applying the diode laser. Results: The results showed that only 3.5-W output power increased the outer surface temperature above the critical value. Conclusion: The recommended output power can be stipulated as equal to or less than 3 W to avoid overheating during diode laser irradiation on thin dentin walls. (c) 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.JBO.17.1.015006]

UV-Ozone Generation from Modified High Intensity Discharge Mercury Vapor Lamps for Treatment of Indium Tin Oxide Films

In a homemade UV-Ozone generator, different ignition tubes extracted from HID mercury vapor lamps were investigated, namely: 80, 125, 250 and 400 watts. The performance of the generator in function of the type of the ignition lamp was monitored by the measurements of the ozone concentration and the temperature increment. The results have shown that the 400 W set up presented the highest ozone production, which was used in the treatment of indium tin oxide (ITO) films. Polymer light emitting diodes were assembled using ITO films, treated for 10, 20 and 30 min, as an anode. The overall results indicate improvement of the threshold voltage (reduction) and electroluminescence of these devices.

Effects of high-intensity intermittent training on carnitine palmitoyl transferase activity in the gastrocnemius muscle of rats

We examined the capacity of high-intensity intermittent training (HI-IT) to facilitate the delivery of lipids to enzymes responsible for oxidation, a task performed by the carnitine palmitoyl transferase (CPT) system in the rat gastrocnemius muscle. Male adult Wistar rats (160-250 g) were randomly distributed into 3 groups: sedentary (Sed, N = 5), HI-IT (N = 10), and moderate-intensity continuous training (MI-CT, N = 10). The trained groups were exercised for 8 weeks with a 10% (HI-IT) and a 5% (MI-CT) overload. The HI-IT group presented 11.8% decreased weight gain compared to the Sed group. The maximal activities of CPT-I, CPT-II, and citrate synthase were all increased in the HI-IT group compared to the Sed group (P < 0.01), as also was gene expression, measured by RT-PCR, of fatty acid binding protein (FABP; P < 0.01) and lipoprotein lipase (LPL; P < 0.05). Lactate dehydrogenase also presented a higher maximal activity (nmol·min-1·mg protein-1) in HI-IT (around 83%). We suggest that 8 weeks of HI-IT enhance mitochondrial lipid transport capacity thus facilitating the oxidation process in the gastrocnemius muscle. This adaptation may also be associated with the decrease in weight gain observed in the animals and was concomitant to a higher gene expression of both FABP and LPL in HI-IT, suggesting that intermittent exercise is a "time-efficient" strategy inducing metabolic adaptation.

Muscular and pulmonary O2 uptake kinetics during moderate- and high-intensity sub-maximal knee-extensor exercise in humans

[EN] The purpose of this investigation was to determine the contribution of muscle O(2) consumption (mVO2) to pulmonary O(2) uptake (pVO2) during both low-intensity (LI) and high-intensity (HI) knee-extension exercise, and during subsequent recovery, in humans. Seven healthy male subjects (age 20-25 years) completed a series of LI and HI square-wave exercise tests in which mVO2 (direct Fick technique) and pVO2 (indirect calorimetry) were measured simultaneously. The mean blood transit time from the muscle capillaries to the lung (MTTc-l) was also estimated (based on measured blood transit times from femoral artery to vein and vein to artery). The kinetics of mVO2 and pVO2 were modelled using non-linear regression. The time constant (tau) describing the phase II pVO2 kinetics following the onset of exercise was not significantly different from the mean response time (initial time delay + tau) for mVO2 kinetics for LI (30 +/- 3 vs 30 +/- 3 s) but was slightly higher (P < 0.05) for HI (32 +/- 3 vs 29 +/- 4 s); the responses were closely correlated (r = 0.95 and r = 0.95; P < 0.01) for both intensities. In recovery, agreement between the responses was more limited both for LI (36 +/- 4 vs 18 +/- 4 s, P < 0.05; r = -0.01) and HI (33 +/- 3 vs 27 +/- 3 s, P > 0.05; r = -0.40). MTTc-l was approximately 17 s just before exercise and decreased to 12 and 10 s after 5 s of exercise for LI and HI, respectively. These data indicate that the phase II pVO2 kinetics reflect mVO2 kinetics during exercise but not during recovery where caution in data interpretation is advised. Increased mVO2 probably makes a small contribution to during the first 15-20 s of exercise.

Effects of recovery mode on performance, O2 uptake, and O2 deficit during high-intensity intermittent exercise

[EN] The aim of this study was to determine the influence of activity performed during the recovery period on the aerobic and anaerobic energy yield, as well as on performance, during high-intensity intermittent exercise (HIT). Ten physical education students participated in the study. First they underwent an incremental exercise test to assess their maximal power output (Wmax) and VO2max. On subsequent days they performed three different HITs. Each HIT consisted of four cycling bouts until exhaustion at 110% Wmax. Recovery periods of 5 min were allowed between bouts. HITs differed in the kind of activity performed during the recovery periods: pedaling at 20% VO2max (HITA), stretching exercises, or lying supine. Performance was 3-4% and aerobic energy yield was 6-8% (both p < 0.05) higher during the HITA than during the other two kinds of HIT. The greater contribution of aerobic metabolism to the energy yield during the high-intensity exercise bouts with active recovery was due to faster VO2 kinetics (p< 0.01) and a higher VO2peak during the exercise bouts preceded by active recovery (p < 0.05). In contrast, the anaerobic energy yield (oxygen deficit and peak blood lactate concentrations) was similar in all HITs. Therefore, this study shows that active recovery facilitates performance by increasing aerobic contribution to the whole energy yield turnover during high-intensity intermittent exercise.