Ambulatory heart rate variability in overweight and obese men after high-intensity interval exercise versus moderate-intensity continuous exercise.

Despite the growing evidence for the beneficial effects of high-intensity interval exercise (HIIE) on vascular health of overweight and obese individuals, it is not clear whether the autonomic stress promoted by HIIE during the ambulatory period is higher than that by moderate-intensity continuous exercise (MICE). Therefore, this study compares the 24 hour (h) ambulatory heart rate variability (HRV) following HIIE and MICE in young overweight and obese men. Eleven untrained men aged 23.2 ± 1.9 years, with average body mass index (BMI) of 31.6 ± 3.9 kg/m² (three overweight and eight obese), underwent three exercise sessions: HIIE, MICE and Control (CT). HRV was recorded in the laboratory and for the next 24 h following laboratory recovery. There were no differences in HRV indices in the rest period between the sessions (p > .05). During the ambulatory period, the area under the curve (AUC) of the low-frequency band transformed into natural logarithm (Ln-LF) during sleep was higher after HIIE than after CT (43.31 ± 8.59 vs. 41.11 ± 7.28 ms²*h, p = .034). The HRV followed by MICE did not differ from other sessions (p > .05). In conclusion, the 24 h ambulatory HRV did not differ after HIIE and MICE. However, despite the small effect, HIIE increased the cardiac autonomic modulation during the sleep period, as a protector of cardiovascular system. Highlights24 h ambulatory HRV could add important information about the cardiovascular safety of the exercise protocols in overweight and obese individuals.There was no disturbances in the cardiac autonomic modulation during the awake period, regardless of the exercise protocol.LnLF index was higher in HIIE compared to CT in the sleep period.24 h ambulatory HRV did not differ between the HIIE and MICE sessions.

Acute Blood Pressure Effects in Older Adults with Hypertension After Different Modalities of Exercise: An Experimental Study.

This study investigated the acute blood pressure (BP) effects of different exercise modalities in older adults with hypertension. Sixty volunteers were randomly assigned (n = 15/group) into different exercise protocols: resistance, bike, water-based exercise (WE), and a control session-all for ∼45 min. Clinic BP measurements were taken before, immediately after, and 15 and 30 min after protocols. The data were analyzed by one-way analysis of variance; generalized estimating equations, following Bonferroni post hoc (p < .05). Immediately after exercise, the systolic BP (SBP) increased in all exercise protocols (resistance exercise = Δ10.3, bike exercise = Δ5.8, WE = Δ9.5 mmHg; p < .001), while the diastolic BP was not altered. Afterward, the SBP reached the value observed before exercise. In Minute 30, only WE presented a significant reduction for SBP (WE = Δ-4.6 mmHg; p < .05). This study has important clinical implications in hemodynamic safety for acute BP increases immediately after exercises, as well as, in the SBP, reduction benefits for older adults with hypertension.

Acute Exercise Increases the Ambulatory Cardiac Modulation of Young Men With Overweight/Obesity.

Purpose: To verify whether excess body mass influences 24-h ambulatory heart rate variability (HRV) after a moderate-intensity continuous exercise (MICE) session. Method: Participants included 27 non-trained young men that were divided into two groups, 1) normal-weight (n = 10) and 2) overweight and obese (n = 17). Participants underwent a single MICE session of 30 minutes at 50-60% of heart rate reserve (HRR), and a control session (CT). Heart rate (HR) and HRV indices were recorded at 60-minute intervals and were used to obtain the area under the curve (AUC) for 24-h ambulatory measurements following MICE or CT. SDNN (standard deviation of RR intervals in milliseconds) and RMSSD (root mean square of successive differences between adjacent RR interval in milliseconds), Ln-LF (log-transformed values of the absolute power of the low-frequency band) and HF (log-transformed values of the absolute power of the high-frequency band) were analyzed. Results: The overweight and obese group presented higher AUC of RMSSD (p = .006), Ln-LF (p = .002), and Ln-HF (p = .005) indices after MICE than CT. Nighttime periods were more responsive to the effects of MICE on RMSSD and Ln-HF indices (p < .05), regardless of group. Conclusion: MICE promoted an increase in the 24-h ambulatory cardiac autonomic modulation in the group overweight and obese, mainly at nighttime during sleep. These results revealed a potential benefit of MICE on the cardiac autonomic modulation for young men with overweight and obesity.

Parasympathetic modulation during sleep time is reduced after maximal exercise, correlated with aerobic fitness in young women / A modulação parassimpática durante o sono é reduzida após o exercício máximo e está correlacionada com a aptidão aeróbia em mulheres jovens

abstract It is known that cardiovascular risk is increased during exercise and recovery. Thus, it is necessary to assess all the risk associated with exercise to minimize the possibility of cardiovascular events. The aim of this study was to verify whether a maximal exercise alters ambulatory cardiac autonomic modulation in untrained women and whether aerobic fitness is correlated to cardiac autonomic modulation. Twelve women (25.35 ± 5.44 years) were outfitted with the Holter monitor on an experimental (after maximum exercise) and a control day to heart rate variability (HRV) evaluation. Maximal exercise increased 24 h heart rate (82 ± 14 vs 77 ± 11 bpm; p = 0.04) and during sleep time (72 ± 14 vs. 65 ± 9 bpm; p = 0.01), reduced parasympathetic modulation (HF - n.u. 49.96 ± 11.56 vs 42.10 ± 14.98; p = 0.04), and increased low-frequency/high-frequency ratio (2.88 ± 3.24 vs 1.31 ± 0.60; p = 0.03) during sleep time compared to the control day. Aerobic fitness was correlated positively with LF, HF, and HF (n.u.) indices (r = 0.61 to 0.73, p < 0.05) and correlated negatively with LF (n.u.) and LF/HF ratio (Rho = - 0.57 to - 0.69; p < 0.05). Maximal exercise alters parasympathetic modulation during sleep time in untrained women. Ambulatory cardiac autonomic modulation after exercise is related to aerobic fitness.

resumo Sabe-se que o risco cardiovascular aumenta durante o exercício e sua recuperação. Assim, é necessário avaliar todo o risco associado ao exercício para minimizar a chance de eventos cardiovasculares. Objetivou-se verificar se um exercício máximo altera a modulação autonômica cardíaca ambulatorial em mulheres não treinadas e se a aptidão aeróbia está correlacionada à modulação autonômica cardíaca. Doze mulheres (25,35 ± 5,44 anos) foram equipadas com monitor Holter em um dia experimental (após exercício máximo) e dia controle para avaliação da variabilidade da frequência cardíaca (VFC). O exercício máximo aumentou a frequência cardíaca de 24 h (82 ± 14 vs 77 ± 11 bpm; p = 0,04) e durante o sono (72 ± 14 vs 65 ± 9 bpm; p = 0,01), bem como reduziu a modulação parassimpática (HF - nu 49,96 ± 11,56 vs 42,10 ± 14,98; p = 0,04) e aumentou a razão de baixa frequência / alta frequência - LF/HF (2,88 ± 3,24 vs 1,31 ± 0,60; p = 0,03) durante o período do sono em comparação com o dia controle. A aptidão aeróbia foi correlacionada positivamente com os índices LF, HF e HF (nu) (r = 0,61 a 0,73, p <0,05) e negativamente correlacionada com LF (nu) e razão LF / HF (Rho = - 0,57 a - 0,69; p <0,05). O exercício máximo altera a modulação parassimpática durante o sono em mulheres não treinadas. A modulação autonômica cardíaca ambulatorial após o exercício foi correlacionada com a aptidão aeróbia.

A single physical education session improves subsequent academic performance in rural school students / Uma única aula de educação física melhora o desempenho acadêmico subsequente em estudantes de escola rural / Una única clase de educación física mejora el posterior desempeño académico en alumnos de escuela rural

ABSTRACT Introduction: Activity breaks or physical exercise interventions in schools are linked to better cognitive function in adolescents. However, few studies have evaluated the relationship between physical exercise and cognition in rural schools, where drop-out levels tend to be higher and academic achievement lower. Objective: To analyze the effects of a physical exercise class (PE) on subsequent academic performance of students, and how they felt during mathematics (MATH) and Portuguese language (PL) tests. Methods: Thirty-six students (14.9 ± 1.5 years) randomly carried out 30 min of PE, performed at 74.3 ± 11.8%HRmax, while a control group (CON) remained seated watching a movie, prior to the tests (PE-MATH; PE-PL; CON-MATH; CON-PL). Results: The PE-MATH group presented higher scores (5.3 ± 2.2) than the CON-MATH group (4.0 ± 2.2). The tests were completed more quickly in PE-PL (7.8 ± 3.3 minutes) than in CON-PL (10.5 ± 4.2 minutes). The number of correct answer per minute was higher in PE-MATH and PE-PL (0.52 ± 0.25; 0.64 ± 0.51) than in CON-MATH and CON-PL (0.35 ± 0.19; 0.41 ± 0.41). Furthermore, 38.9% of PE-MATH felt more focused during the test, while only 16.7% of CON-MATH felt more focused. During the Portuguese language test, 27.8% of CON-PL complained of greater apprehensiveness, compared to 8.3% for PE-PL. Also, 36.1% reported feeling fatigued during PL after PE, compared to 8.3% in the CON-PL group. Conclusions: PE improved the adolescents' academic performance. Despite feeling fatigue, more students who performed physical exercise felt less apprehensive and more focused during the tests after PE. Level of evidence I; STARD: studies of diagnostic accuracy.

RESUMO Introdução: Os intervalos com atividade ou as intervenções com programas de exercícios na escola estão relacionados com a melhora da função cognitiva em adolescentes. Contudo, poucos estudos avaliaram a relação entre exercício físico e cognição em escolas de zonas rurais, onde os níveis de evasão são altos e o rendimento acadêmico é baixo. Objetivo: Analisar os efeitos de uma aula de exercício físico (EF) sobre o desempenho acadêmico subsequente dos alunos e o que sentem durante os testes de matemática (MAT) e de língua portuguesa (PO). Métodos: Trinta e seis estudantes (14,9 ± 1,5 anos) foram divididos randomicamente em dois grupos: um com 30 minutos de EF realizados a 74,3 ± 11,8% da FCmáx e um controle (CON), que permaneceram sentados assistindo a um filme antes dos testes (EF-MAT; EF-PO; CON-MAT; CON-PO). Resultados: O EF-MAT apresentou maior escore (5,3 ± 2,2) que o CON-MAT (4,0 ± 2,2). Os testes foram concluídos mais rapidamente no EF-PO (7,8 ± 3,3) do que no CON-PO (10,5 ± 4,2). O número de respostas corretas por minuto foi maior no EF-MAT e no EF-PO (0,52 ± 0,25; 0,64 ± 0,51) do que no CON-MAT e no CON-PO (0,35 ± 0,19; 0,41 ± 0,41). Além disso, 38,9% do EF-MAT sentiram que estavam mais concentrados durante o teste, em comparação com apenas 16,7% do CON-MAT que se sentiram mais concentrados. Durante o a prova de português, 27,8% dos CON-PO reclamaram de maior apreensão quando comparados com 8,3% do EF-PO. Ainda, 36,1% relataram cansaço durante o teste de PO depois de EF, comparados com 8,3% do grupo CON-PO. Conclusão: A aula de EF melhorou o desempenho acadêmico dos adolescentes. Apesar da sensação de cansaço, mais estudantes sentiram menos apreensão e estavam mais concentrados durante os testes depois de EF. Nível de evidência I; Estudos de acurácia diagnóstica (STARD).

RESUMEN Introducción: Los intervalos con actividad o las intervenciones con programas de ejercicios en la escuela están relacionados con la mejora de la función cognitiva en adolescentes. Sin embargo, pocos estudios evaluaron la relación entre ejercicio físico y cognición en escuelas de zonas rurales, en donde los niveles de evasión son altos y el rendimiento académico es bajo. Objetivo: Analizar los efectos de una clase de ejercicio físico (EF) sobre el desempeño académico subsiguiente de los alumnos y lo que sienten durante los tests de matemática (MAT) y de idioma portugués (PO). Métodos: Treinta y seis estudiantes (14,9 ± 1,5 años) fueron divididos aleatoriamente en dos grupos: uno con 30 minutos de EF realizados a 74,3 ± 11,8% de la FCmáx y un control (CON), que permanecieron sentados viendo una película antes de los tests (EF-MAT; EF-PO; CON-MAT; CON-PO). Resultados: El EF-MAT presentó mayor puntuación (5,3 ± 2,2) que el CON-MAT (4,0 ± 2,2). Los tests fueron concluidos más rápidamente en el EF-PO (7,8 ± 3,3) que en el CON-PO (10,5 ± 4,2). El número de respuestas correctas por minuto fue mayor en el EF-MAT y en el EF-PO (0,52 ± 0,25,0,64 ± 0,51) que en el CON-MAT y en el CON-PO (0,35 ± 0,19, 0,41 ± 0,41). Además, 38,9% del EF-MAT sintió que estaba más concentrado durante el test, en comparación con sólo 16,7% del CON-MAT que se sintió más concentrado. Durante la prueba de portugués, 27,8% de los CON-PO reclamó de mayor aprehensión cuando comparado con 8,3% del EF-PO. Además, 36,1% relató cansancio durante el test de PO después del EF, comparado con el 8,3% del grupo CON-PO. Conclusión: La clase de EF mejoró el desempeño académico de los adolescentes. A pesar de la sensación de cansancio, más estudiantes sintieron menos aprehensión y estaban más concentrados durante los tests después de EF. Nivel de evidencia I; Estudios de precisión diagnóstica (STARD).

Reproducibility of Heart Rate Variability Indices at Post-maximal Exercise.

To analyze whether heart rate variability is reproducible after maximal exercise, 11 men (22.1±3.2 years) performed four incremental exercise tests followed by passive or active recovery. There was high reliability (intraclass coefficient correlation: 0.72-0.96) and fair-to-excellent agreement (coefficient of variation: 7.81-22.09%) in passive recovery, as well as moderate-to-high reliability (intraclass coefficient correlation: 0.50-0.87) and good agreement (coefficient of variation: 11.08-20.89%) in active recovery for LnRMSSD index. There was moderate-to-high reliability (intraclass coefficient correlation: 0.51-0.81) and good agreement (coefficient of variation: 10.41-18.87%) in most of the analyzed time points, in both recovery types for LnSDNN. In both types of recovery, the time domain heart rate variability 5-10 min indices (passive: intraclass coefficient correlation : 0.87-0.88; coefficient of variation: 7.67-13.44%; active: intraclass coefficient correlation 0.59-0.80; coefficient of variation: 14.62-16.26%) presented higher intraclass coefficient correlation and lower coefficient of variation than the spectral heart rate variability indices (passive: intraclass coefficient correlation: 0.71-0.87; coefficient of variation: 12.33-34.21%; active: intraclass coefficient correlation: 0.46-0.77; coefficient of variation: 24.41-105.12%). The LnRMSSD and LnSDNN indices analyzed in 30 s segments and the heart rate variability 5-10 min indices after maximal exercise in untrained healthy men showed satisfactory reproducibility, regardless of the type of recovery, with the time-domain indices showing higher reproducibility than the frequency-domain indices.

Acute effects of moderate-intensity and high-intensity exercise on hemodynamic and autonomic reactivity to the cold pressor test in young adults with excess body weight.

OBJECTIVE: To investigate the effects of a single session of moderate-intensity and high-intensity interval exercise in cardiovascular reactivity to the cold pressor test in young adults with excess body weight. METHODS: Twenty-two subjects with excess body weight (23 ± 2 years; 30.0 ± 3.4 kg·m) performed three sessions: (1) moderate-intensity exercise (30-minute cycling at 50%-60% of heart rate reserve); (2) high-intensity exercise (four series of 3-minute cycling at 80%-90% of heart rate reserve, interspersed by 2-minute recovery) and (3) control (i.e. 30-minute seated). Before and 30 minutes after the interventions, subjects undertook assessments of SBP/DBP and heart rate in response to the cold pressor test (1-minute rest + 1-minute hand immersed in 4°C water). Reactivity was calculated as the absolute response of SBP, DBP and heart rate to cold pressor test and compared between interventions using a two-way analysis of variance (P < 0.05). RESULTS: Neither moderate-intensity exercise or high-intensity interval exercise attenuated SBP/DBP reactivity to cold pressor test compared with control. On the other hand, heart rate reactivity was reduced after moderate-intensity exercise compared with control (1.36 ± 8.35 bpm vs. 5.18 ± 9.45 bpm). Furthermore, moderate-intensity exercise reduced absolute levels of SBP/DBP from pre- to post-intervention. CONCLUSION: A single session of moderate-intensity exercise or high-intensity interval exercise did not reduce the SBP/DBP reactivity to cold pressor test. However, absolute levels of SBP/DBP were lower after moderate-intensity exercise, indicating a hypotensive effect promoted by a single session of moderate-intensity exercise in young adults with excess body weight.

Aerobic fitness and recovery type influence post-exercise heart rate in young women / Aptidão aeróbia e tipo de recuperação influenciam a frequência cardíaca pós-exercício em mulheres jovens

This study aimed to analyze both influence of aerobic fitness and active recovery in heart rate (HR) reduction after maximum exercise (i.e. maximum incremental test) in untrained young women. Seventeen women were evaluated (23.88 ± 4.85 years), divided by the medium of peak of consumption of oxygen (30.80 mL. kg-1.min-1), in higher or lower aerobic fitness obtained during a maximum incremental test performed on a cycle ergometer. The post-exercise recovery was performed actively and passively, on two randomly non-consecutive days. It was noticed that HR at 6th and from the 6th to 10th min after the passive and active recovery, respectively, was lower in the higher aerobic fitness group, beyond that, the values of %HR reduction from the 6th to 10th min at 6th min after passive and active recovery, respectively, were higher in the higher aerobic fitness group. After active recovery, HR in 8th and 9th min and %HR reduction of the 8th to 10th min were lower and higher, respectively (p<0.05) than passive recovery in the lower aerobic fitness group. In short, the aerobic fitness influenced HR reduction after maximum exercise in untrained young women, mainly, after passive recovery. Besides that, the active recovery showed benefits in HR reduction in lower aerobic fitness group....(AU)

O presente estudo teve como objetivo analisar a influência da aptidão aeróbia e recuperação ativa na redução da frequência cardíaca (FC) após o exercício máximo (teste incremental máximo) em mulheres jovens não treinadas. Foram avaliadas dezessete mulheres jovens (23,88 ± 4,85 anos), divididas pela mediana do consumo pico de oxigênio (30,80 mL∙kg-1 ∙min-1 ), em maior ou menor aptidão aeróbia obtida durante um teste incremental máximo. A recuperação pós-exercício foi realizada de forma ativa e passiva, em dois dias experimentais randomizados e não consecutivos. Foi observado que, a FC foi menor no grupo de maior aptidão aeróbia no 6º min após a recuperação passiva e do 6º ao 10º min após a recuperação ativa, além disso, os valores do percentual de redução da FC foram maiores no grupo de maior aptidão aeróbia do 6º ao 10º min e no 6º min após a recuperação passiva e ativa, respectivamente. Após a recuperação ativa, a FC no 8º e 9º min e o percentual de redução da FC do 8º ao 10º min foram menores e maiores, respectivamente (p <0,05) do que após a recuperação passiva no grupo com menor aptidão aeróbia. Em suma, a aptidão aeróbia influenciou na redução da FC pós-exercício máximo em mulheres jovens não treinadas, principalmente após a recuperação passiva. Além disso, a recuperação ativa auxiliou na redução da FC no grupo com menor aptidão aeróbia....(AU)

Isolated Obesity Is Not Enough to Impair Cardiac Autonomic Modulation in Metabolically Healthy Men.

PURPOSE: To evaluate whether excess body mass influences the heart rate variability (HRV) indexes at rest, and to correlate adiposity indicators and the aerobic fitness with cardiac autonomic variables in metabolically healthy young adults. METHOD: In all, 41 untrained males (Mage = 21.80, SD = 2.14 years), 14 normal weight (MBMI = 22.28, SD = 1.86 kg∙m-2), 11 overweight (MBMI = 26.95, SD = 1.43 kg∙m-2), and 16 obese (MBMI = 33.58, SD = 3.06 kg∙m-2) metabolically healthy (normal values of blood pressure, fasting blood glucose, triglycerides, and total cholesterol), underwent evaluations of the HRV at rest and of the peak oxygen consumption (VO2 peak) during maximal exercise on a cycle ergometer. RESULTS: Blood pressure, heart rate, HRV indexes, casual blood glucose, oxidative stress, and antioxidant activity did not differ among the groups. The VO2 peak (mL∙kg-1∙min-1) was lower in the obese group compared with the normal weight and overweight groups. The body mass (r = -.40 to -.45) and abdominal circumference (r = -.39 to -.52) were slightly to moderately correlated with SD1, SD2, RMSSD, SDNN, pNN50, LF, and HF indexes and total power. The VO2 peak (mL∙kg-1∙min-1) was slightly to moderately correlated (r = .48 to .51) with SD2, SDNN, and LF indexes in the individuals with excess body mass. CONCLUSION: Cardiac autonomic modulation at rest was preserved in metabolically healthy obese young men. However, the indicators of adiposity, as well as the aerobic fitness were correlated with cardiac autonomic modulation in the individuals with excess body mass.

Reproducibility of Heart Rate Variability Threshold in Untrained Individuals.

The aim of this study was to evaluate the reproducibility of the heart rate variability threshold (HRVT) by different HRV indexes and determination criteria. 68 untrained participants, 17 women (24.09±4.91 years old; 21.54±1.97 kg∙m-2) and 51 men (24.52±3.52 years old; 26.51±6.31 kg∙m-2), were evaluated on 2 different days (test and retest). The HRVT was determined during an incremental exercise test using 2 indexes (SD1 and RMSSD) and criteria (HRTV1, first intensity of physical effort with index<3 ms, and HRVT2, first intensity of physical effort, in which the index presents a difference<1 ms between 2 consecutive intensities). There was no significant difference (p<0.05) between the test and retest for any of the variables evaluated. All variables, except for the rate of perceived exertion at HRVT2, presented moderate to high intraclass correlation coefficient (HRVT1: 0.55-0.85 and HRVT2:0.58-0.69). All variables at HRVT1 and the heart rate at HRVT2 showed coefficient of variation ~ 10%. The HRVT, regardless of criteria and HRV index used, showed satisfactory reproducibility. Thus, these criteria can be used to assess clinically autonomic cardiac modulation and aerobic capacity, and to analyze the effect of different interventions.

Predicted Equation for VO2 Based on a 20-Meter Multistage Shuttle Run Test for Children.

This study compared maximum oxygen consumption (VO2max) on a 20-meter multistage shuttle run test (20-Srt) with a cardiopulmonary exercise test (CPET) to determine a VO2max prediction equation for a 20-Srt in children aged 6-10 years. Eighty healthy children performed the CPET on a treadmill, while the 20-Srt took place on a sports court. Heart rate (HR) was measured and the expired gases were continuously measured breath-by-breath using a portable gas analyzer. The VO2max was lower (p<0.05) in CPET than 20-Srt for all, female, and male participants, respectively (46.3±7.9 vs. 48.7±4.6; 42.7±7.8 vs. 46.7±4.8; 49.3±6.8 vs. 50.4±3.9, mL·kg-1·min-1). The standard error estimates were between 3.0 and 3.6 and considered as not clinically relevant if less than 5 mL·kg-1·min-1. The intraclass correlation coefficient between the VO2 in CPET and in 20-Srt was 0.74 (CI95% 0.55-0.84) and considered moderately reliable. The linear multiple regression excluded sex, body mass index and fat-free mass and retained the maximum speed and age in the predictive equation. The 20-Srt estimates the VO2max with moderate reliability and the predictive equation was VO2maxpred=4.302+(maximum speed*5.613)-(age*1.523) for children aged 6-10 years.

Photobiomodulation Leads to Reduced Oxidative Stress in Rats Submitted to High-Intensity Resistive Exercise.

The aim of this study was to determine whether oxidative stress markers are influenced by low-intensity laser therapy (LLLT) in rats subjected to a high-intensity resistive exercise session (RE). Female Wistar rats divided into three experimental groups (Ctr: control, 4J: LLLT, and RE) and subdivided based on the sampling times (instantly or 24 h postexercise) underwent irradiation with LLLT using three-point transcutaneous method on the hind legs, which was applied to the gastrocnemius muscle at the distal, medial, and proximal points. Laser (4J) or placebo (device off) were carried out 60 sec prior to RE that consisted of four climbs bearing the maximum load with a 2 min time interval between each climb. Lipoperoxidation levels and antioxidant capacity were obtained in muscle. Lipoperoxidation levels were increased (4-HNE and CL markers) instantly post-RE. LLLT prior to RE avoided the increase of the lipid peroxidation levels. Similar results were also notified for oxidation protein assays. The GPx and FRAP activities did not reduce instantly or 24 h after RE. SOD increased 24 h after RE, while CAT activity did not change with RE or LLLT. In conclusion, LLLT prior to RE reduced the oxidative stress markers, as well as, avoided reduction, and still increased the antioxidant capacity.

Higher blood pressure and lower cardiac vagal activity in obese young individuals in supine and seated position.

BACKGROUND: Obesity triggers alterations in hemodynamic and autonomic control. There are few studies that investigate the effects of overweight and obesity in early adulthood on hemodynamic and autonomic variables. AIM: The aim of this study was to determine whether overweight and obesity in young individuals cause alterations in hemodynamic parameters and heart rate variability (HRV) in supine and seated position, and to correlate these variables with anthropometric features. METHODS: Measurements were performed in 40 young untrained male study participants. The subjects were eutrophic (22.8 ± 0.3 kg/m2, N = 19), overweight (27.0 ± 0.5 kg/m2, N = 10), and obese (33.5 ± 0.8 kg/m2, N = 11). After 5 min in supine and seated position, the R-R intervals and blood pressure (BP) were recorded. RESULTS: The systolic blood pressure were higher in overweight (supine, 122.9 ± 2.3 mmHg) and obese (supine, 123.9 ± 2.2; seated, 121.7 ± 2.3 mmHg) individuals compared to eutrophic individuals (supine, 111.8 ± 1.64; seated, 111.3 ± 1.8 mmHg) (p ⩽ 0.05). Obese subjects exhibited lower HRV (SD1, RMSSD, pNN50) compared to eutrophic individuals when seated. In obese subjects, the heart rate (HR) increased and HRV decreased (p ≤ 0.05) when seated versus supine position. The body mass, body mass index (BMI), and waist and abdominal circumferences correlated positively with BP (r = 0.40-0.64, p ≤ 0.05), while the BMI, waist circumference, BP, and HR were negatively correlated (r = -0.32 -0.62, p ≤ 0.05) with HRV (pNN50 and HF) in both body positions. BMI, waist circumference, BP and HR correlated negat- ively with additional HRV indices (SD1, SD2, RMSSD, TP, and LF) when seated. CONCLUSIONS: Obese and overweight individuals presented higher SBP, and obese individuals had lower HRV and cardiac vagal activity, associated with anthropometric variables. RELEVANCE FOR PATIENTS: The monitoring of HRV in obese subjects in seated position allows improved prognosis of metabolic consequences to cardiac autonomic control.

Water aerobics is followed by short-time and immediate systolic blood pressure reduction in overweight and obese hypertensive women.

One exercise training session such as walking, running, and resistance can lead to a decrease in blood pressure in normotensive and hypertensive individuals, but few studies have investigated the effects of exercise training in an aquatic environment for overweight and obese hypertensive individuals. We aimed to assess the acute effects of a water aerobics session on blood pressure changes in pharmacologically treated overweight and obese hypertensive women. A randomized crossover study was carried out with 18 hypertensive women, 10 of them were overweight (54.4 ± 7.9 years; body mass index: 27.8 ± 1.7 kg/m(2)) and eight obese (56.4 ± 6.6 years; body mass index: 33.0 ± 2.0 kg/m(2)). The water aerobics exercise session consisted of a 45-minute training at the intensity of 70%-75% of maximum heart rate adjusted for the aquatic environment. The control group did not enter the pool and did not perform any exercise. We measured systolic blood pressure (SBP) and diastolic blood pressure (DBP) before, immediately after, and every 10 minutes up to 30 minutes after the aerobic exercise or control session. Overall (n = 18), DBP did not change after the water aerobic exercise and control session, and SBP decreased at 10 and 20 minutes postexercise compared to the control session. Among overweight women, SBP decreased at 10 and 20 minutes postexercise. In contrast, among obese women, SBP decreased only at 10 minutes postexercise. SBP variation was -2.68 mm Hg in overweight and -1.24 mm Hg in obese women. In conclusion, the water aerobics session leads to a reduction in SBP, but not in DBP, during 10 and 20 minutes postexercise recovery. Thus, it may be safely prescribed to overweight and obese women.

Does Stroke Volume Increase During an Incremental Exercise? A Systematic Review.

INTRODUCTION: Cardiac output increases during incremental-load exercise to meet metabolic skeletal muscle demand. This response requires a fast adjustment in heart rate and stroke volume. The heart rate is well known to increase linearly with exercise load; however, data for stroke volume during incremental-load exercise are unclear. Our objectives were to (a) review studies that have investigated stroke volume on incremental load exercise and (b) summarize the findings for stroke volume, primarily at maximal-exercise load. METHODS: A comprehensive review of the Cochrane Library's, Embase, Medline, SportDiscus, PubMed, and Web of Sci-ence databases was carried out for the years 1985 to the present. The search was performed between February and June 2014 to find studies evaluating changes in stroke volume during incremental-load exercise. Controlled and uncontrolled trials were evaluated for a quality score. RESULTS: The stroke volume data in maximal-exercise load are inconsistent. There is evidence to hypothesis that stroke volume increases during maximal-exercise load, but other lines of evidence indicate that stroke volume reaches a plateau under these circumstances, or even decreases. CONCLUSION: The stroke volume are unclear, include contradictory evidence. Additional studies with standardized reporting for subjects (e.g., age, gender, physical fitness, and body position), exercise test protocols, and left ventricular function are required to clarify the characteristics of stroke volume during incremental maximal-exercise load.

LIMIAR ANAERÓBIO A PARTIR DA PSE EM EXERCÍCIO RESISTIDO POR MODELOS MATEMÁTICOS / ANAEROBIC THRESHOLD FROM PE IN RESISTANCE EXERCISE BY MATHEMATICAL MODELS / UMBRAL ANAERÓBICO DE EP EN EL EJERCICIO DE FUERZA POR LOS MODELOS MATEMÁTICOS

Introdução: O limiar anaeróbio é comumente identificado em exercícios cíclicos, contudo, também pode ser determinado no exercício resistido (ER) por diferentes métodos, e assim, estimar a carga de trabalho relacionada ao estresse metabólico. No entanto, sua identificação a partir de outros métodos como o modelo matemático da DMáx e principalmente por variáveis mais acessíveis, como a percepção subjetiva de esforço (PSE), ainda não foi analisada. Objetivo: Comparar o limiar de lactato (LL) identificado pelo método de inspeção visual (LLIV) com o método da DMáx aplicado nas respostas do lactato (LLDMáx) e da PSE (PSE12/13 e PSEDMáx) durante exercício resistido incremental. Métodos: Dez praticantes de ER (24,8 ± 3,0 anos) foram submetidos ao teste de uma repetição máxima (1-RM) e a um teste incremental no leg-press, obtendo-se a PSE e o lactato em cada estágio. Resultados: Foi possível identificar o limiar anaeróbio por todos os métodos, entre 30% a 40% de 1-RM. As cargas absolutas, concentrações de lactato sanguíneo e PSE não foram diferentes entre os métodos empregados e apresentaram boa concordância entre si. Conclusão: É possível identificar o limiar anaeróbio tanto por inspeção visual quanto pelo modelo matemático de DMáx para o lactato e PSE, ampliando as possibilidades de determinação do limiar anaeróbio no exercício resistido por métodos de baixo custo e não invasivos.

Introduction: The anaerobic threshold is commonly identified in cyclic exercises, however it can also be identified on resistance exercise (RE) by different methods, and thus can estimate the workload related to metabolic stress. However, its identification by other methods such as mathematical model of DMax and primarily by more accessible variables such as perceived exertion (PE) has not yet been analyzed. Objective: To compare the lactate threshold (LT) identified by visual inspection method (LTVI) with DMax method applied in lactate responses (LTDMax) and PE (PE12/13 and PEDMax) during incremental resistance exercise. Methods: Ten practitioners of RE (24.8±3.0 years) underwent the test of one repetition maximum (1-RM) and an incremental load test in leg-press, obtaining the PE and lactate in each stage. Results: It was possible to identify the anaerobic threshold by all methods, between 30 and 40% of 1-RM. The absolute load, blood lactate concentrations, and PE were not different between the methods used and showed good agreement with each other. Conclusion: It is possible to identify the anaerobic threshold both by visual inspection and by the mathematical model of DMax for lactate and PE, expanding the possibilities for determining the anaerobic threshold in resistance exercise by low cost and non-invasive methods.

Introducción: El umbral anaeróbico se identifica comúnmente en los ejercicios cíclicos, sin embargo, también se puede determinar en el ejercicio de resistencia (ER) por diferentes métodos, y por lo tanto, se puede estimar la carga de trabajo relacionada con el estrés metabólico. No obstante, su identificación por otros métodos como el modelo matemático de DMáx y sobre todo mediante variables más accesibles, como el esfuerzo percibido (EP), todavía no se ha analizado. Objetivo: Comparar el umbral de lactato (UL) identificado por el método de inspección visual (ULIV) con el método DMáx aplicado a las respuestas de lactato (ULDMáx) y EP (EP12/13 y EPDMáx) durante los ejercicios de resistencia incremental. Métodos: Diez practicantes de ER (24,8 ± 3,0 años) fueron sometidos a la prueba de una repetición máxima (1-RM) y una prueba incremental en la prensa de piernas, obteniendo el EP y el lactato en cada etapa. Resultados: Fue posible identificar el umbral anaeróbico por todos los métodos, entre el 30% y el 40% de 1-RM. Las cargas absolutas, las concentraciones de lactato en sangre y EP no fueron diferentes entre los métodos utilizados y mostraron buena concordancia entre sí. Conclusión: Es posible identificar el umbral anaeróbico tanto por inspección visual como por el modelo matemático de DMáx de lactato y el EP, ampliando las posibilidades de determinar el umbral anaeróbico en el ejercicio de resistencia por métodos de bajo costo y no invasivos.

Blood pressure and cardiac autonomic modulation at rest, during exercise and recovery time in the young overweight

This study aimed to assess the blood pressure (BP), cardiac autonomic modulation at rest, in physical exercise and in the recovery in untrained eutrophic (E) and overweight (O) youth. The body mass index (BMI), waist circumference (WC), systolic BP-SBP (E: 109.80 ± 10.05; O: 121.85 ± 6.98 mmHg) and diastolic BP - DBP (E: 65.90 ± 7.28; O: 73.14 ± 12.22 mmHg) were higher in overweight and the heart rate recovery (%HRR) was lower as compared with E volunteers. The BMI was associated with SBP (r= 0.54), DBP (r= 0.65), load on the heart rate variability threshold - HRVT (r= -0.46), %HRR 2' (r= -0.48) and %HRR 5' (r= -0.48), and WC was associated with SBP (r= 0.54), DBP (r= 0.64) and HRR 2' (r= -0.49). The %HRR was associated to SBP, DBP and HRVT. In summary, the anthropometric variables, BP and cardiac autonomic modulation in the recovery are altered in overweight youth.

High-intensity, but not moderate-intensity, exercise increases post-exercise rate of fat oxidation in type 2 diabetics.

BACKGROUND: Aerobic exercise is recommended for glycemic and weight control in type 2 diabetes (T2D), but exercise intensity that increase post-exercise fat oxidation has not been established yet. It is expected that high-intensity exercise induce higher absolute oxidations and rates of oxidation of CHO (during) and fat (after) in normoglycemic, but in hyperglycemic it is unclear. AIM: To compare the effects of exercise intensity on CHO and fat oxidation during and after exercise in individuals with T2D. METHODS: Eleven persons with T2D, randomly underwent three experimental sessions 72 hours apart: 1) 20 minute of high-intensity exercise (120% of lactate threshold (LT) - 120%LT), 2) 20 minute of moderate-intensity exercise (80% of LT - 80%LT), and 3) 20 minute of control session (CON) - no exercise was performed and the individuals remained seated during the whole time. Percentages of CHO and fat contribution and CHO and fat oxidation rate (mg/min) were analyzed during and after sessions. RESULTS: The rate of CHO oxidation during exercise was significantly higher during 120%LT in relation to 80%LT and CON (18.2 ± 5.6 vs. 9.5 ± 2.7 vs. 1.1 ± 0.4 mg∙min-1), the absolute rate of fat oxidation was significantly higher in 120%LT compared to 80%LT and CON during exercise (13.5 ± 3.3, 9.5 ± 2.2, and 0.7 ± 0.2 mg∙min-1, respectively, p < 0.05). During the post-exercise oxygen consumption recovery period, only the 120%LT had higher fat oxidation (94.5% vs. 68.1%, p < 0.05), when compared to CON. Both exercise sessions equally elicited a lowered glycaemia during the post-exercise period, but CHO oxidation was lower after 120%LT than CON (0.1 ± 0.2 vs. 0.9 ± 0.5 mg∙min-1, p < 0.05). CONCLUSIONS: Higher intensity elicited an elevated CHO oxidation rate during exercise and a higher percentage of fat utilization during the post-exercise recovery period compared to moderate-intensity exercise and control sessions. RELEVANCE FOR PATIENTS: High-intensity aerobic exercise, even of short duration, may benefit individuals with T2D on the substrate oxidation related to the body fat. Exercise can be an important tool for the prevention and management of T2D due to its effects on carbohydrate and fat metabolism, reduction of body fat, and control of blood glucose.