The potential role of physical activity and a healthy diet in increasing nitric oxide during COVID-19 outbreak.

The potential role of physical activity and a healthy diet in increasing nitric oxide during COVID-19 outbreak. This manuscript presents a perspective which provide new insights about the promising role of nitric oxide on COVID-19. Demonstration that nitric oxide was an important cornerstone against viral infections, including SARS-CoV-1 in 2009. Thus, given the concern that higher NO- could improve endothelial health and might be a protection factor against COVID-19, should we critically consider non-pharmacological strategies that increase NO- bioavailability as medicine for COVID-19? From this perspective, we highlight the potential effect of physical activity and healthy diet in stimulating the increase of NO- bioavailability.

Les rôles potentiels de l'activité physique et d'une alimentation saine dans l'augmentation de l'oxyde nitrique pendant l'épidémie de COVID-19. Ce manuscrit présente une perspective qui fournit de nouvelles informations sur le rôle prometteur de l'oxyde nitrique sur la protection contre le risque de COVID-19. Dès 2009, a été évoqué le rôle de l'oxyde nitrique contre le risque d'infections virales, y compris contre la première pandémie liée au coronavirus SARS-CoV-1. Compte tenu de l'hypothèse qu'une augmentation de la production de NO− permettrait d'améliorer la santé endothéliale et pourrait être un facteur de protection contre COVID-19, la question se pose sur la promotion de stratégies non pharmacologiques qui augmentent la biodisponibilité du NO−. C'est dans cette perspective que sont, ici, discutés les effets potentiels de l'activité physique et d'une alimentation saine pour stimuler l'augmentation de la biodisponibilité du NO et la prévention contre la COVID-19.

Bradykinin, insulin, and glycemia responses to exercise performed above and below lactate threshold in individuals with type 2 diabetes.

The aim of this study was to analyze the acute responses of bradykinin, insulin, and glycemia to exercise performed above and below lactate threshold (LT) in individuals with type 2 diabetes mellitus (T2D). Eleven participants with a diagnosis of T2D randomly underwent three experimental sessions 72 h apart: 1) 20 min of exercise performed at 120% of LT (120%LT), 2) 20 min of exercise performed at 80% of LT (80%LT), and 3) 20 min of control session. Blood glucose was analyzed before, during, and at 45 min post-exercise. Bradykinin and insulin were analyzed before and at 45 min post-exercise. Both exercise sessions elicited a parallel decrease in glucose level during exercise (P≤0.002), with a greater decrease being observed for 120%LT (P=0.005). Glucose decreased 22.7 mg/dL (95%CI=10.3 to 35, P=0.001) at the 45 min post-exercise recovery period for 80%LT and decreased 31.2 mg/dL (95%CI=18.1 to 44.4, P<0.001) for 120%LT (P=0.004). Insulin decreased at post-exercise for 80%LT (P=0.001) and control (P≤0.035). Bradykinin increased at 45 min post-exercise only for 80%LT (P=0.013), but was unrelated to the decrease in glucose (r=-0.16, P=0.642). In conclusion, exercise performed above and below LT reduced glycemia independently of insulin, but exercise above LT was more effective in individuals with T2D. However, these changes were unrelated to the increase in circulating bradykinin.

One session of partial-body cryotherapy (-110 °C) improves muscle damage recovery.

To evaluate the effects of a single session of partial-body cryotherapy (PBC) on muscle recovery, 26 young men performed a muscle-damaging protocol that consisted of five sets of 20 drop jumps with 2-min rest intervals between sets. After the exercise, the PBC group (n = 13) was exposed to 3 min of PBC at -110 °C, and the control group (n = 13) was exposed to 3 min at 21 °C. Anterior thigh muscle thickness, isometric peak torque, and muscle soreness of knee extensors were measured pre, post, 24, 48, 72, and 96 h following exercise. Peak torque did not return to baseline in control group (P < 0.05), whereas the PBC group recovered peak torques 96 h post exercise (P > 0.05). Peak torque was also higher after PBC at 72 and 96 h compared with control group (P < 0.05). Muscle thickness increased after 24 h in the control group (P < 0.05) and was significantly higher compared with the PBC group at 24 and 96 h (P < 0.05). Muscle soreness returned to baseline for the PBC group at 72 h compared with 96 h for controls. These results indicate that PBC after strenuous exercise may enhance recovery from muscle damage.

Correlation between acute and chronic 24-hour blood pressure response to resistance training in adult women.

The purpose of the present study was to correlate the acute and chronic decrease in blood pressure (BP) following resistance training (RT). 13 normotensive women (18-49 years) completed an acute whole body RT session with 3 sets of 10 repetitions at 60% 1RM and then 8 weeks of RT as follows: 3/week, 3 sets of 8-12 repetitions maximum. Systolic (SBP) and diastolic BP (DBP) were measured up to 60 min and 24 h following RT (acute and chronic). The greatest acute decrease of SBP (108.5±7.0 mmHg) and DBP (71.5±6.4 mmHg) values over the 60-min period were reduced compared to pre-exercise (117.3±11.7 and 79.3±8.2 mmHg, respectively; p<0.05). The chronic effect on resting BP was observed only for those presenting acute post-exercise hypotension (PEH). The change in both SBP and DBP following acute RT was correlated with the chronic change in resting SBP and DBP (r>0.5; p≤0.05). The change in 24 h BP after acute RT was correlated with the chronic reduction in SBP (r=0.74) and DBP (r=0.80). The magnitude of PEH is a promising candidate for the prediction of individual BP-related training efficacy.

Effects of a single whole body cryotherapy (-110°C) bout on neuromuscular performance of the elbow flexors during isokinetic exercise.

It has been demonstrated that body cooling may decrease neuromuscular performance. However, the effect of a single session of whole body cryotherapy (-110°C) on neuromuscular performance has not been well documented. Thus, the aim of this study was to evaluate the effects of a single exposure of WBC on elbow flexor neuromuscular performance. Thirteen physically active, healthy young men (age=27.9±4.2 years, mass=79.4±9.7 kg, height=176.7±5.2 cm) were randomly exposed to 2 different experimental conditions separated by a minimum of 72 h: 1) whole body cryotherapy- 3 min at -110°C; 2) control- 3 min at 21°C. All subjects were tested for maximal isokinetic elbow flexion at 60°.s(-1) 30 min before and 10 min after each condition. There were no significant differences in peak torque, average power, total work or muscle activity between conditions. Peak torque was lower at post-test compared to pre-test in both conditions (F=6.58, p=0.025). However, there were no differences between pre-test and post-test for any other variables. These results indicate that strength specialists, athletic trainers and physical therapists might utilize whole body cryotherapy before training or rehabilitation without compromising neuromuscular performance of the elbow flexors.

Effects of partial-body cryotherapy (- 110°C) on muscle recovery between high-intensity exercise bouts.

The aim of this study was to evaluate the effects of a single partial-body cryotherapy bout between training sessions on strength recovery. 12 young men (23.9±5.9 years) were randomly exposed to 2 different conditions separated by 7 days: 1) Partial-body cryotherapy (subjects were exposed to 3 min of partial-body cryotherapy at - 110 °C between 2 high-intensity training sessions); 2) Control (subjects were not exposed to partial-body cryotherapy between 2 high-intensity training sessions). Subjects were exposed to partial-body cryotherapy after the first training session. The 2 knee extension high-intensity training sessions were separated by a 40-min rest interval. Knee extension training consisted of 6 sets of 10 repetitions at 60°.s(-1) for concentric actions and 6 sets of 10 at 180.s(-1) for eccentric actions. The decrease in eccentric peak torque and total work was significantly (p<0.05) less after partial-body cryotherapy (5.6 and 2%, respectively) when compared to control (16 and 11.6%, respectively). However, the decrease in concentric peak torque and total work was not different (p>0.05) between partial-body cryotherapy (9.4 and 6.5%, respectively) and control (7.5 and 5.2%, respectively). These results indicate that the use of partial-body cryotherapy between-training sessions can enhance eccentric muscle performance recovery.

Effect of 12 weeks of resistance exercise on post-exercise hypotension in stage 1 hypertensive individuals.

Post-exercise hypotension (PEH), the reduction of blood pressure (BP) after a single bout of exercise, is of great clinical relevance. As the magnitude of this phenomenon seems to be dependent on pre-exercise BP values and chronic exercise training in hypertensive individuals leads to BP reduction; PEH could be attenuated in this context. Therefore, the aim of the present study was to investigate whether PEH remains constant after resistance exercise training. Fifteen hypertensive individuals (46 ± 8 years; 88 ± 16 kg; 30 ± 6% body fat; 150 ± 13/93 ± 5 mm Hg systolic/diastolic BP, SBP/DBP) were withdrawn from medication and performed 12 weeks of moderate-intensity resistance training. Parameters of cardiovascular function were evaluated before and after the training period. Before the training program, hypertensive volunteers showed significant PEH. After an acute moderate-intensity resistance exercise session with three sets of 12 repetitions (60% of one repetition maximum) and a total of seven exercises, BP was reduced post-exercise (45-60 min) by an average of aproximately -22 mm Hg for SBP, -8 mm Hg for DBP and -13 mm Hg for mean arterial pressure (P<0.05). However, this acute hypotensive effect did not occur after the 12 weeks of training (P>0.05). In conclusion, our data demonstrate that PEH, following an acute exercise session, can indeed be attenuated after 12 weeks of training in hypertensive stage 1 patients not using antihypertensive medication.

Haemophilia and exercise.

One of the most important objectives of intervention programs for persons with haemophilia (PWH) is to improve their quality of life. Regular physical activity has been recommended as an adjunct to conventional treatment, with positive results in the prevention of joint problems and bleeding, in addition to the improvement in cardiovascular function, muscle strength, and body composition. The objective of the present review was to present the benefits of aerobic and resistance training programs in PWH, as well to discuss the best exercise dose-response in the different levels of disease severity. We considered randomized controlled trials, study cases and literature reviews from MEDLINE and Highwire databases. After a detailed analysis of the studies involving exercise for PWH, it can be concluded that this intervention elicits some benefits for physical fitness and blood coagulation mechanisms, suggesting the application of physical training as a non pharmacological treatment in association with conventional treatment. Adequate and periodized resistance training considering the disease severity, accompanied by physical education professionals could improve muscle strength, balance and proprioception. In addition, aerobic training could reduce the risks of obesity and several metabolic and cardiovascular diseases. Exercise can improve several outcomes of quality in PWH.

Maximal lactate steady state is altered in the heat.

The aim of this study was to compare the maximal lactate steady state (MLSS) and ventilatory threshold (VT) under different environments (TEMP: 22°C; and HOT: 40°C; 50% RH). 8 male subjects (age 23.9±2.4 years, body mass 75.9±7.3 kg and VO2(max) 47.8±4.9 mL·kg(-1)·min(-1)) performed a series of tests to determine the peak workload (W(peak)), VT and MLSS on a cycle ergometer. W(peak) was higher in the TEMP as compared to the HOT condition (225±9 W vs. 195±8 W, respectively; p<0.05). The workload at MLSS was higher at 22°C (180±11 W) than 40°C (148±11 W; p<0.05), as well as VT at 22°C (156±9 W) was higher than 40°C (128±6 W). Likewise, the blood lactate concentration at MLSS was higher at 22°C (5.60±0.26 mM) than 40°C (4.22±0.48 mM; p<0.05). The mean of heart rate (HR) was not statistically different between TEMP (168±3 bpm) and HOT (173±3 bpm) at MLSS, despite being different at trials between the 25(th) and the 30(th) min of exercise. The HR at VT was significantly higher in HOT (153±4 bpm) as compared to the TEMP (145±2 bpm). Our results suggest that environmental conditions may influence the determination of MLSS and VT. Moreover, VT was appropriate for estimation of the workload at MLSS in the HOT.

Acute resistance exercise is more effective than aerobic exercise for 24h blood pressure control in type 2 diabetics.

AIM: The study aimed to analyze blood pressure (BP) responses in individuals with type 2 diabetes (T2D) over a 24h period following resistance (RES) and aerobic (AER) exercise. METHODS: Ten adults with T2D (age: 55.8 ± 7.7 years; weight: 79.4 ± 14.0 kg; fasting glucose: 133.0 ± 36.7 mg.dL⁻¹) underwent: (1) AER: 20 min of cycling at 90% lactate threshold (90% LT); (2) RES: three laps of a circuit of six exercises with eight repetitions at 70% 1-RM and 40s of recovery; and (3) a control session of no exercise. Heart rate (HR), and systolic (SBP), diastolic (DBP), mean arterial (MAP) and pulse (PP) BP, as well as lactataemia (Lac), VO(2), respiratory exchange ratio (RER) and rate of perceived exertion (RPE) were measured at rest, during exercise and control (CON) periods, and 60min after interventions. After each session, BP was also monitored over a 24h period. RESULTS: Peak Lac (RES: 6.4 ± 1.4mM; AER: 3.8 ± 1.2mM), RER (RES: 1.1 ± 0.1; AER: 0.9 ± 0.1) and RPE (RES: 14.0 ± 1.3; AER: 11.0 ± 2.3) were higher following the RES session (P < 0.05). Similar VO2 (~70% VO(2peak)) was reached during AER and RES sessions (14.0 ± 3.0 vs 14.3 ± 1.6 mL.kg.min⁻¹; P > 0.05). Compared with CON, only RES elicited post-exercise BP reduction that lasted 8h after exercise. Also, in comparison to pre-exercise rest, the BP dip during sleep was greater following RES (P < 0.05). CONCLUSION: A single exercise bout decreases BP in T2D patients over a 24h period, with RES being more effective than AER exercise for BP control.

Effect of type 2 diabetes on plasma kallikrein activity after physical exercise and its relationship to post-exercise hypotension.

AIM: The present study was undertaken to determine the effects of type 2 diabetes (T2D) on plasma kallikrein activity (PKA) and postexercise hypotension (PEH). METHODS: Ten T2D patients (age: 53.6±1.3 years; body mass index: 30.6±1.0kg/m(2); resting blood glucose: 157.8±40.2mgdL(-1)) and 10 non-diabetic (ND) volunteers (age: 47.5±1.0 years; body mass index: 28.3±0.9kg/m(2); resting blood glucose: 91.2±10.5mgdL(-1)) underwent two experimental sessions, consisting of 20min of rest plus 20min of exercise (EXE) at an intensity corresponding to 90% of their lactate threshold (90LT) and a non-exercise control (CON) session. Blood pressure (BP; Microlife BP 3AC1-1 monitor) and PKA were measured during rest and every 15min for 135min of the postexercise recovery period (RP). RESULTS: During the RP, the ND individuals presented with PEH at 30, 45 and 120min (P<0.05) while, in the T2D patients, PEH was not observed at any time. PKA increased at 15min postexercise in the ND (P<0.05), but not in the T2D patients. CONCLUSION: T2D individuals have a lower PKA response to exercise, which probably suppresses its hypotensive effect, thus reinforcing the possible role of PKA on PEH.

Blood glucose minimum predicts maximal lactate steady state on running.

This study analyzed if the running speed corresponding to glucose minimum (GM) could predict the maximal lactate steady state (MLSS). Thirteen physically active men (25.2+/-4.2 years, 73.4+/-8.0 kg, 180.0+/-1.0 cm) completed three running tests on different days: 1) a 1 600-m time trial to calculate the average speed; 2) after 10-min of recovery from a 150-m sprint to elevate [lac], participants performed 6 series of 800-m respectively at 78, 81, 84, 87, 90 and 93% of the 1 600-m speed to identify the lactate minimum (LM) and GM speeds and 3) 2-4 constant intensity exercise sessions for the MLSS. Repeated measures ANOVA showed no differences between running speeds associated to the GM (201.7+/-23.8 m.min (-1)), LM (200.0+/-23.9 m.min (-1)) and MLSS (201.5+/-23.1 m.min (-1)), with high correlation between GM vs. LM (r=0.984), GM vs. MLSS (r=0.947) and LM vs. MLSS (r=0.961) (P<0.01). Bland and Altman plots showed good agreement [Bias (+/-95% CI)] for MLSS and GM [0.2(15.3) m.min (-1)], MLSS and LM [-1.4(13.2) m.min (-1)], as well as for LM and GM [1.7(8.5) m.min (-1)]. These running speeds occurred at approximately 84.4% of 1 600-m speed, which would have practical applications for exercise prescription. We concluded that GM running speed is a good predictor of the MLSS for physically active individuals.

Acute exercise performed close to the anaerobic threshold improves cognitive performance in elderly females

The objective of the present study was to compare the effect of acute exercise performed at different intensities in relation to the anaerobic threshold (AT) on abilities requiring control of executive functions or alertness in physically active elderly females. Forty-eight physically active elderly females (63.8 ± 4.6 years old) were assigned to one of four groups by drawing lots: control group without exercise or trial groups with exercise performed at 60, 90, or 110 percent of AT (watts) and submitted to 5 cognitive tests before and after exercise. Following cognitive pretesting, an incremental cycle ergometer test was conducted to determine AT using a fixed blood lactate concentration of 3.5 mmol/L as cutoff. Acute exercise executed at 90 percent of AT resulted in significant (P < 0.05, ANOVA) improvement in the performance of executive functions when compared to control in 3 of 5 tests (verbal fluency, Tower of Hanoi test (number of movements), and Trail Making test B). Exercising at 60 percent of AT did not improve results of any tests for executive functions, whereas exercise executed at 110 percent of AT only improved the performance in one of these tests (verbal fluency) compared to control. Women from all trial groups exhibited a remarkable reduction in the Simple Response Time (alertness) test (P = 0.001). Thus, physical exercise performed close to AT is more effective to improve cognitive processing of older women even if conducted acutely, and using a customized exercise prescription based on the anaerobic threshold should optimize the beneficial effects.

Acute exercise performed close to the anaerobic threshold improves cognitive performance in elderly females.

The objective of the present study was to compare the effect of acute exercise performed at different intensities in relation to the anaerobic threshold (AT) on abilities requiring control of executive functions or alertness in physically active elderly females. Forty-eight physically active elderly females (63.8 +/- 4.6 years old) were assigned to one of four groups by drawing lots: control group without exercise or trial groups with exercise performed at 60, 90, or 110% of AT (watts) and submitted to 5 cognitive tests before and after exercise. Following cognitive pretesting, an incremental cycle ergometer test was conducted to determine AT using a fixed blood lactate concentration of 3.5 mmol/L as cutoff. Acute exercise executed at 90% of AT resulted in significant (P < 0.05, ANOVA) improvement in the performance of executive functions when compared to control in 3 of 5 tests (verbal fluency, Tower of Hanoi test (number of movements), and Trail Making test B). Exercising at 60% of AT did not improve results of any tests for executive functions, whereas exercise executed at 110% of AT only improved the performance in one of these tests (verbal fluency) compared to control. Women from all trial groups exhibited a remarkable reduction in the Simple Response Time (alertness) test (P = 0.001). Thus, physical exercise performed close to AT is more effective to improve cognitive processing of older women even if conducted acutely, and using a customized exercise prescription based on the anaerobic threshold should optimize the beneficial effects.

Polynomial modeling for the identification of lactate minimum velocity by different methods.

AIM: The lactate minimum (LM) protocol has been used to assess aerobic fitness and to predict exercise intensity associated with the maximal blood lactate steady state. The aim of this study was to compare different methods to identify the lactate minimum velocity (LMV) on cycling. METHODS: Fourteen male cyclists (26.8+/-4.5 years; 173.2+/-6.1 cm; 67.3+/-5.2 kg; 5,8+/-2.9 years of training) performed the LM test in a velodrome. The protocol consisted of an all out 2 km time trial to elevate blood lactate (bLAC), followed by 8 min of recovery and then 6 bouts of 2 km starting 5 kmxh(-1) below the individual mean velocity for the 6 km performance. The velocity was incremented by 1 kmxh(-1) at each bout with 25 microL of capillary blood being collected for bLAC measurements (YSI 2700 STAT). The LMV was identified visually (vLMV), and by applying a second grade polynomial function on 6 (pLMV(6)) and 3 (pLMV(3)) incremental bouts. Additionally, a method where the bLACx work velocity(-1) quotients (LMVQ) were plotted against the correspondent velocity during the incremental test, identified the LMV by considering 6 (LMVQ(6)) or 3 bouts (LMVQ(3)). RESULTS: ANOVA showed no differences between vLMV (33.1+/-2.5 kmxh(-1)), pLMV(6) (32.9+/-2.5 kmxh(-1)), pLMV(3) (33.2+/-2.3 kmxh(-1)), LMVQ(6) (32.8+/-2.5 kmxh(-1)) and LMVQ(3) (33.4+/-2.3 kmxh(-1)), with high correlation among them. CONCLUSIONS: It was possible to identify the LMV by the methods proposed in the present study, even when the results of only 3 bouts of the test were modeled by polynomial function. Such an approach enables a more practical and economical test in addition to minimizing the discomfort due to several blood collections.

Respostas cardiovasculares durante a postura sentada da Reeducação Postural Global (RPG) / Cardiovascular responses in the seated posture of the Global Postural Reeducation (GPR) method

OBJETIVO: Avaliar as respostas da freqüência cardíaca (FC), pressão arterial sistólica (PAS), diastólica (PAD), média (PAM) e duplo produto (DPr), durante a postura sentada do método de Reeducação Postural Global (RPG). MATERIAIS E MÉTODOS: Nove voluntárias saudáveis (23±2,1 anos, 56,4±7,8kg, 1,61±0,05m, 21,6±2,4kg.m2-1), inexperientes na prática do método RPG, foram submetidas a uma sessão de RPG na postura sentada, realizada em três fases: repouso pré-postura, execução da postura e recuperação pós-postura. No repouso e na recuperação, as voluntárias permaneceram sentadas por 20 minutos, sendo PA e FC verificadas a cada cinco minutos. A fase de execução da postura foi realizada em três séries e mantida por três minutos cada, com intervalo de um minuto entre elas. A verificação da PA e da FC foi realizada a cada um minuto e 30 segundos de execução da postura. RESULTADOS: Os valores de PAS, PAD, PAM e DPr foram significativamente maiores (p<0,05) do terceiro ao nono minuto da execução da postura (154±14, 107±11, 122±9mmHg e 16.478±2.802mmHg.min-1) quando comparados aos valores de repouso pré-postura (109±10, 74±7, 85±8mmHg e 9.374±1.687mmHg.min-1) e aos valores de recuperação pós-postura. Porém, estes valores retornaram aos valores de repouso nos primeiros cinco minutos de recuperação pós-postura. Durante a execução da postura, a FC não foi estatisticamente diferente da FC de repouso pré-postura. CONCLUSÕES: Elevações significativas da PAS, PAD, PAM e DPr foram observadas durante a execução da postura sentada da RPG empregada nesse estudo, mas retornaram aos valores de repouso nos primeiros cinco minutos de recuperação pós-postura.

OBJECTIVE: To evaluate heart rate (HR), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP) and double product (DP) responses in the seated posture of the Global Postural Reeducation (GPR) method. METHODS: Nine healthy female volunteers (23±2.1 years; 56.4±7.8kg; 1.61±0.05m, 21.6±2.4kg/m²), without experience of the GPR, method underwent a treatment session in the seated posture. It was a three-step experiment: pre-posture resting, posture maintenance and post-posture recovery. In both the resting and the recovery step, the volunteers remained seated for 20 minutes and arterial pressure and HR were measured every five minutes. The posture maintenance step lasted for three minutes and was implemented three times with one-minute intervals between implementations. Arterial pressure and HR were measured every 1.5 minutes, while the posture was being maintained. RESULTS: The SAP, DAP, MAP and DP values were significantly greater (p<0.05) from the third to the ninth minute of maintaining the posture (154±14, 107±11, 122±9mmHg and 16,478±2,802mmHg/min) in comparison with the pre-posture resting values (109±10, 74±7, 85±8mmHg and 9,374±1,687mmHg/min) and the post-posture recovery values. However, these values returned to the resting values within the first five minutes of post-posture recovery. The HR while maintaining the posture was not statistically different from the pre-posture resting HR. CONCLUSIONS: Significant increases in SAP, DAP, MAP and DP were observed while maintaining the seated posture of the GPR method that was used in this study, but these values returned to the resting values within the first five minutes of post-posture recovery.

Identificação do limiar anaeróbio em indivíduos com diabetes tipo-2 sedentários e fisicamente ativos / Identification of the anaerobic threshold in sedentary and physically active individuals with type 2 diabetes

OBJETIVO: Comparar intensidades de limiar anaeróbio (LA) obtidas a partir do lactato, ventilação e glicemia em diabéticos tipo-2 ativos (DA) e sedentários (DS) e não-diabéticos ativos (NDA), e correlacionar variáveis metabólicas, hemodinâmicas e de composição corporal com o LA. METODOLOGIA: Grupos de DS (n= 09, 56,7 ± 11,9 anos), DA (n= 09, 50,6 ± 12,7 anos) e NDA (n= 10, 48,1 ± 10,8 anos) foram submetidos a um teste em cicloergômetro com incrementos de 15W até a exaustão. Freqüência cardíaca, pressão arterial (PA), percepção de esforço, lactato, glicemia e variáveis ventilatórias foram mensuradas nos 20seg finais de cada estágio de 3min para determinação dos limiares de lactato, ventilatório e glicêmico. RESULTADOS: As intensidades associadas ao LA identificado pelos diferentes métodos não diferiram entre si (p> 0,05). As intensidades absolutas foram menores para o grupo DS em relação aos grupos ativos (p< 0,05), não sendo observadas diferenças entre os grupos para as intensidades relativas ao consumo máximo de oxigênio ( por centoVO2 pico) e potência máxima ( por centoPpico) de ocorrência do LA. Observou-se correlação significativa entre LA e o percentual de gordura (r= -0,52), com tendência à correlação entre o LA e a glicemia ambulatorial (r= -0,33). Variáveis hemodinâmicas e LA não demonstraram correlações. CONCLUSÃO: O LA foi identificado a partir das técnicas estudadas em diabéticos tipo-2 e não-diabéticos. Apesar das diferenças entre grupos para as intensidades absolutas (Watts), a patologia pareceu não influenciar as intensidades relativas em que o LA foi observado. O LA apresentou correlação com a composição corporal e tendência a se correlacionar com a glicemia ambulatorial, sugerindo-se, com isso, o LA como um parâmetro importante na avaliação clínica destes pacientes.

OBJECTIVE: To compare anaerobic threshold (AT) intensities determined from blood lactate, blood glucose and ventilatory responses among sedentary (SD) and physically active (AD) type-2 diabetics and active non-diabetics (AND), and to correlate metabolic, hemodynamic and body composition variables with the AT. METHOD: The SD (n= 9, 56.7 ± 11.9 years), AD (n= 9, 50.6 ± 12.7 years) and AND (n= 10, 48.1 ± 10.8 years) groups performed a cycle ergometer test with increases of 15 watts every three minutes until exhaustion. Heart rate, arterial pressure, perceived exertion, blood lactate, blood glucose and ventilatory variables were measured during the last 20 seconds of each incremental stage, to determine the lactate, ventilatory and glucose thresholds. RESULTS: The AT intensities identified by the different methods did not differ from each other (p> 0.05). However, the absolute intensities were lower for SD than for the active groups (p< 0.05). No differences in intensity were found between the groups in relation to maximum oxygen consumption ( percentVO2 peak) and maximum power ( percentPpeak) at which the AT was observed. There was a significant correlation between AT and percentage fat (r= -0.52), and there was a trend towards correlation between AT and ambulatory blood glucose (r= -0.33). The hemodynamic variables did not show any correlations with AT. CONCLUSION: The AT was identified by means of the techniques studied, among type 2 diabetics and non-diabetics. Despite the differences between the groups with regard to absolute intensities (watts), diabetes did not appear to influence the relative intensities at which the AT was observed. The AT presented a correlation with body composition and a trend towards correlation with ambulatory blood glucose, thus suggesting that the AT is an important parameter in clinical assessments for such patients.

Relationships and significance of lactate minimum, critical velocity, heart rate deflection and 3 000 m track-tests for running.

AIM: The running velocities associated to lactate minimum (V(lm)), heart rate deflection (V(HRd)), critical velocity (CV), 3.000 m (V(3000)) and 10 000 m performance (V10km) were compared. Additionally the ability of V(lm) and V(HRd) on identifying sustainable velocities was investigated. METHODS: Twenty runners (28.5+/-5.9 y) performed 1) 3,000 m running test for V3000; 2) an all-out 500 m sprint followed by 6x800 m incremental bouts with blood lactate ([lac]) measurements for V(lm); 3) a continuous velocity-incremented test with heart rate measurements at each 200 m for V(HRd); 4) participants attempted to 30 min of endurance test both at V(lm)(ETV(lm)) and V(HRd)(ETV(HRd)). Additionally, the distance-time and velocity-1/time relationships produced CV by 2 (500 m and 3 000 m) or 3 predictive trials (500 m, 3,000 m and distance reached before exhaustion during ETV(HRd)), and a 10 km race was recorded for V10km. RESULTS: The CV identified by different methods did not differ to each other. The results (m.min(-1)) revealed that V(lm) (281+/-14.8)

Blood glucose responses in humans mirror lactate responses for individual anaerobic threshold and for lactate minimum in track tests.

The equilibrium point between blood lactate production and removal (La-(min)) and the individual anaerobic threshold (IAT) protocols have been used to evaluate exercise. During progressive exercise, blood lactate [La-]b, catecholamine and cortisol concentrations, show exponential increases at upper anaerobic threshold intensities. Since these hormones enhance blood glucose concentrations [Glc]b, this study investigated the [Glc] and [La-]b responses during incremental tests and the possibility of considering the individual glucose threshold (IGT) and glucose minimum (Glc(min)) in addition to IAT and La-(min) in evaluating exercise. A group of 15 male endurance runners ran in four tests on the track 3000 m run (v3km); IAT and IGT - 8 x 800 m runs at velocities between 84% and 102% of v3km; La-(min) and Glc(min) - after lactic acidosis induced by a 500-m sprint, the subjects ran 6 x 800 m at intensities between 87% and 97% of v3km; endurance test (ET) - 30 min at the velocity of IAT. Capillary blood (25 microl) was collected for [La-]b and [Glc]b measurements. The IAT and IGT were determined by [La-]b and [Glc]b kinetics during the second test. The La-(min) and Glc(min) were determined considering the lowest [La-] and [Glc]b during the third test. No differences were observed (P < 0.05) and high correlations were obtained between the velocities at IAT [283 (SD 19) and IGT 281 (SD 21) m. x min(-1); r = 0.096; P < 0.001] and between La-(min) [285 (SD 21)] and Glc(min) [287 (SD 20) m. x min(-1) r = 0.77; P < 0.05]. During ET, the [La-]b reached 5.0 (SD 1.1) and 5.3 (SD 1.0) mmol x l(-1) at 20 and 30 min, respectively (P > 0.05). We concluded that for these subjects it was possible to evaluate the aerobic capacity by IGT and Glc(min) as well as by IAT and La-(min).