The effects of home-based progressive resistance training in chronic kidney disease patients

INTRODUCTION

Faced with lockdowns, it was mandatory the development of supervised home-based RT protocols to keep patients with chronic kidney disease engaged in programs. Nonetheless, there is a lack of scientific literature regarding its effects on patients.

PURPOSE

To investigate the effects of a supervised home-based progressive resistance training program on functional performance, bone mineral density, renal function, endothelial health, inflammation, glycemic homeostasis, metabolism, redox balance, and the modulation of exerkines in patients with CKD in stage 2.

METHODS

Patients (n = 31) were randomized and allocated into the control group (CTL; n = 15; 58.07 ± 5.22 yrs) or resistance training group (RT; n = 16; 57.94 ± 2.74 yrs). RT group performed 22 weeks of supervised progressive home-based resistance exercises. Bone mineral density, anthropometric measurements, and functional performance were assessed. Venous blood samples were collected at baseline and after the intervention for the analysis of markers of renal function, endothelial health, inflammation, glycemic homeostasis, metabolism, and redox balance.

RESULTS

Twenty-two weeks of home-based RT were effective in improving (P < 0.05) functional performance, bone mineral density, uremic profile, ADMA, inflammatory markers, the Klotho-FGF23 axis, glycemic homeostasis markers, and exerkines. These improvements were accompanied by higher concentrations of exerkines and anti-inflammatory cytokines. RT group displayed a decrease in cases of osteopenia after the intervention (RT: 50 % vs. CTL: 86.7 %; X² = 4.763; P = 0.029).

CONCLUSION

Results provide new evidence that supervised home-based progressive RT may be a relevant intervention to attenuate the progression of CKD and improve functional capacity, bone mineral density, and the immunometabolic profile. These improvements are associated with positive modulation of several exerkines.

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.

Are Physical Fitness and CRP Related to Framingham Risk Score in HIV+ Adults?

Background. People living with HIV (PLWH) have increased risk of cardiovascular disease (CVD). The Framingham Risk Score (FRS) predicts a 10-year CVD risk. Its relationships to physical fitness and C-reactive protein (CRP) are not well established. The current aim is to determine the links between FRS, physical fitness, and CRP in PLWH. Methods. Participants (n = 87) were assessed on multiple biomarkers. The FRS was calculated with the respective variables. Other variables that correlated significantly with FRS were entered into a regression equation to determine their relationship to FRS. Results. The FRS for men was more than twice that for women (12.8 vs 6.0, P < .001). Men were more fit than women, but most participants were not fit. Aerobic capacity was predictive of FRS in men, but not in women, and muscular strength was not predictive of FRS. Women had more than double the CRP compared with men (7.9 vs 3.5 mg/L, P < .01), and it was unrelated to FRS. Conclusions. In men, aerobic capacity was significantly predictive of FRS, but muscular strength and CRP were unrelated to FRS in both genders. These results do not conclusively demonstrate that physical fitness and CRP are related to FRS in PLWH.

Influence of Angiotensin Converting Enzyme I/D Polymorphism on Hemodynamic and Antioxidant Response to Long-Term Intradialytic Resistance Training in Patients With Chronic Kidney Disease: A Randomized Controlled Trial

ABSTRACT

Corrêa, HdL, Deus, LA, Neves, RVP, Reis, AL, de Freitas, GS, de Araújo, TB, da Silva Barbosa, JM, Prestes, J, Simões, HG, Amorim, CE, dos Santos, MAP, Haro, A, de Melo, GF, Gadelha, AB, Neto, LS, and Rosa, TdS. Influence of angiotensin converting enzyme I/D polymorphism on hemodynamic and antioxidant response to long-term intradialytic resistance training in patients with chronic kidney disease: a randomized controlled trial. J Strength Cond Res 35(10): 2902-2909, 2021-The aim of the study was to verify the influence of Angiotensin-converting enzyme (ACE) I/D genotype on blood pressure, muscle mass, and redox balance response to long-term resistance training (RT) in end-stage renal disease patients. Three hundred and twenty subjects were randomized into 4 groups: II + ID control (II + ID CTL, n = 80), II + ID RT (II + ID RT, n = 79), DD control (DD CTL n = 83), and DD RT (DD RT, n = 78). The RT lasted 24 weeks with a frequency of 3 times per week, on alternative days. Each section consisted of 3 sets of 8-12 repetitions in 11 exercises, with training loads at 6 point (somewhat hard) to 8 point (hard) based on OMNI-RES scale and was prescribed during dialysis (intradialytic). Statistical significance was accepted with p < 0.05. The most relevant benefits in blood pressure were found for DD homozygotes (p < 0.0001), whereas allele I carriers displayed a higher increase in muscle mass (p < 0.0001). Hemodialysis clinics that already use RT for their patients could include the genotyping of ACE to identify the predisposal of the patients to respond to RT and to counteract kidney disease-related comorbidities.

Telomere Length, SIRT1, and Insulin in Male Master Athletes: The Path to Healthy Longevity?

Lower SIRT1 and insulin resistance are associated with accelerated telomere shortening. This study investigated whether the lifestyle of master athletes can attenuate these age-related changes and thereby slow aging. We compared insulin, SIRT1, and telomere length in highly trained male master athletes (n=52; aged 49.9±7.2 yrs) and age-matched non-athletes (n=19; aged 47.3±8.9 yrs). This is a cross-sectional study, in which all data were collected in one visit. Overnight fasted SIRT1 and insulin levels in whole blood were assessed using commercial kits. Relative telomere length was determined in leukocytes through qPCR analyses. Master athletes had higher SIRT1, lower insulin, and longer telomere length than age-matched non-athletes (p<0.05 for all). Insulin was inversely associated with SIRT1 (r=-0.38; p=0.001). Telomere length correlated positively with SIRT1 (r=0.65; p=0.001), whereas telomere length and insulin were not correlated (r=0.03; p=0.87). In conclusion, master athletes have higher SIRT1, lower insulin, and longer telomeres than age-matched non-athletes. Furthermore, SIRT1 was negatively associated with insulin and positively associated with telomere length. These findings suggest that in this sample of middle-aged participants reduced insulin, increased SIRT1 activity, and attenuation of biological aging are connected.

Influence of Body Fat on Oxidative Stress and Telomere Length of Master Athletes

ABSTRACT

Aguiar, SS, Rosa, TS, Sousa, CV, Santos, PA, Barbosa, LP, Deus, LA, Rosa, EC, Andrade, RV, and Simões, HG. Influence of body fat on oxidative stress and telomere length of master athletes. J Strength Cond Res 35(6): 1693-1699, 2021-The present investigation analyzed the role of body fat and training history on biological aging of master athletes by comparing and verifying the relationships between markers of adiposity, oxidative balance, and telomere length (TL) in middle-aged runners and untrained individuals. Master athletes (sprinters and endurance runners, n = 21; 51.62 ± 8.19 years) and untrained age-matched controls (n = 11; 45.41 ± 10.34 years) had blood samples collected for biochemical and biomolecular analyzes. Pro-oxidant and antioxidant measures as well as DNA extraction were performed using commercial kits. Relative TL (T/S) was determined in leukocytes through quantitative polymerase chain reaction analyses. Master athletes had lower body fat and longer TL than untrained controls (body fat: 12.21 ± 4.14% vs. 26.03 ± 4.29%; TL: 1.10 ± 0.84 vs. 0.56 ± 0.56 T/S; p < 0.05). Furthermore, master athletes also showed a better oxidative balance than untrained controls (p < 0.05). A negative correlation was observed between TL and body fat (r = -0.471; p = 0.007), and conicity index (r = -0.407; p = 0.021), catalase activity (r = -0.569; p = 0.001), and CAT/TBARS ratio (r = -0.463; p = 0.008) for the whole sample. In conclusion, master athletes have longer TL, better oxidative profile, and lower body fat than untrained individuals. Moreover, for this middle-aged sample, body fat was inversely correlated with both TL and markers of oxidative balance, demonstrating the key role of adiposity in biological aging.

Master athletes have longer telomeres than age-matched non-athletes. A systematic review, meta-analysis and discussion of possible mechanisms

The aim of this systematic review and meta-analysis was 1) to assess whether master athletes have longer telomeres than age-matched non-athletes and 2) discuss possible underlying mechanisms underlying telomere length preservation in master athletes. A literature search was performed in PubMed, Web of Science, Scopus and SPORTDiscus up to August 2020. Only original articles published in peer-reviewed journals that compared telomere length between master athletes and aged-matched non-athletes were included. Eleven studies fulfilled eligibility criteria and were included in the final analysis. Overall, 240 master athletes (51.9±7.5 years) and 209 age-matched non-athletes (50.1±9.1 years) were analyzed. Master athletes had been participating in high-level competitions for approximately 16.6 years. Pooled analyses revealed that master athletes had longer telomeres than aged-matched non-athletes (SMD=0.89; 95% CI=0.45 to 1.33; p<0.001). Master athletes showed lower pro-oxidant damage (SMD=0.59; 95% CI=0.26 to 0.91; p<0.001) and higher antioxidant capacity (SMD=-0.46; 95% CI=-0.89 to -0.03; p=0.04) than age-matched non-athletes. Further, greater telomere length in master athletes is associated with lower oxidative stress and chronic inflammation, and enhanced shelterin protein expression and telomerase activity. In conclusion, 1) master athletes have longer telomeres than age-matched non-athletes, which may be the result of 2) lower levels of oxidative stress and chronic inflammation, and elevated shelterin expression and telomerase activity.

Dynamic not isometric training blunts osteo-renal disease and improves the sclerostin/FGF23/Klotho axis in maintenance hemodialysis patients: a randomized clinical trial

This study compared the effectiveness of dynamic resistance training (DRT) versus isometric RT (IRT) on osteogenesis and hormonal mechanisms involved in maintenance hemodialysis (MHD) patients. One hundred and ninety-three MHD patients were randomized into three groups: control (CTL) (n = 60), DRT (n = 66), and IRT (n = 67). A first visit was required for an anamnesis to evaluate the number of medications, biochemical, and anthropometric measurements (dialysis adequacy, creatinine, urea, body mass, height, and body mass index). Grip strength, bone mineral density (BMD), and renal-bone markers were assessed pre- and postprotocol. The DRT and IRT training was 6 mo with a frequency of three times per week, on alternate days. Each training session consisted of three sets of 8 to 12 repetitions at lower and moderate intensities. Both training sessions were prescribed approximately 1 h prior to dialysis. Statistical significances were adopted with P < 0.05. There was a greater dropout in the IRT group (24%) as compared with the DRT group (14%), which in turn had less adverse clinical effects (67%, 24%, and 61% for CTL, DRT, and IRT, respectively). DRT promoted gains in BMD in different body locations, in addition to increasing pro-osteogenic factors (Klotho and calcitriol) and reducing those related to bone loss, such as sclerostin, FGF23, and PTH. There was an improvement in Ca × PO₄³ for DRT, whereas these benefits did not occur in the IRT group (P < 0.05). These novel findings suggest that the DRT generates biopositive adaptations in bone tissue in MHD and can be used as a nonpharmacological strategy to improve BMD.NEW & NOTEWORTHY This study shows, for the first time, the effect of dynamic and isometric resistance training on bone mineral density in hemodialysis patients, providing a new understanding of the possible participation of the sclerostin/FGF23/Klotho axis, vitD, PTH, and calcium × phosphate product in this process. However, isometric resistance training may not be sufficient to induce these benefits. Therefore, this study supports the potential therapeutic role of dynamic resistance training counteracting chronic kidney disease-mineral and bone disorder.

Breaking the athletics world record in the 100 and 400 meters: an alternative method for assessment

BACKGROUND

The top 10 athletes in the International Association of Athletic Federations in 100-m and 400-m ranking for each sex were assessed for their history of race times before achieving their personal record (PR). The main goal of this study was to create a new method for optimal performance improvement rate assessment for coaches and athletes aiming the World Record.

METHODS

The difference between PR ('current' season) and the best race time in the last season was defined as the first season improvement rate (1-SIR), whereas the average improvement rate in the last and preceding seasons was the multi-season improvement rate (M-SIR). 1-SIR and M-SIR were calculated for each athlete.

RESULTS

The sex comparison for the 100 m event showed a significant difference in the M-SIR in favor of women. No statistical differences were identified for the 400 m event, with a trivial effect in both 1-SIR and M-SIR.

CONCLUSIONS

As a practical applicability, graph plots were designed to help verifying the improvement rate of athletes and to evaluate whether a long-term training strategy induced an acceptable performance improvement or whether some adjustments needed and check within the plots if the improvement rate is within the average of the top-10 athletes of their event.

Combined effects of very short "all out" efforts during sprint and resistance training on physical and physiological adaptations after 2 weeks of training

PURPOSE

The aim of this study was to compare the combined effects of resistance and sprint training, with very short efforts (5 s), on aerobic and anaerobic performances, and cardiometabolic health-related parameters in young healthy adults.

METHODS

Thirty young physically active individuals were randomly allocated into four groups: resistance training (RTG), sprint interval training (SITG), concurrent training (CTG), and control (CONG). Participants trained 3 days/week for 2 weeks in the high-intensity interventions that consisted of 6-12 "all out" efforts of 5 s separated by 24 s of recovery, totalizing ~ 13 min per session, with 48-72 h of recovery between sessions. Body composition, vertical jump, lower body strength, aerobic and anaerobic performances, heart rate variability (HRV), and redox status were evaluated before and after training. Total work (TW), rating of perceived exertion (CR-10 RPE) and mean HR (HR_mean) were monitored during sessions. Incidental physical activity (PA), dietary intake and perceived stress were also controlled.

RESULTS

Maximum oxygen consumption (VO_2max) significantly increased in SITG and CTG (P < 0.05). Lower body strength improved in RTG and CTG (P < 0.05), while countermovement jump (CMJ) was improved in RTG (P = 0.04) only. Redox status improved after all interventions (P < 0.05). No differences were found in TW, PA, dietary intake, and psychological stress between groups (P > 0.05).

CONCLUSIONS

RT and SIT protocols with very short "all out" efforts, either performed in isolation, or combined, demonstrated improvement in several physical fitness- and health-related parameters. However, CT was the most efficient exercise intervention with improvement observed in the majority of the parameters.

Psychophysiological characterization of different capoeira performances in experienced individuals: A randomized controlled trial

The aim of this study was to characterize the psychophysiological demand in different capoeira performances. Eleven experienced capoeira practitioners underwent the following procedures in different days: 1) anamnesis and anthropometric measurements; 2) aerobic performance assessment; 3 to 5) performances of 90 seconds in three capoeira styles (Angola, Benguela and São Bento), which were performed in randomized controlled cross-over design. The psychophysiological demand was assessed through the heart rate (HR), R-R interval (RRi), blood pressure (BP), blood lactate ([Lac]), blood glucose ([Gluc]), rating perceived effort (RPE), feeling scale (FS) and perceived activation (PA). Descriptive statistics with mean and standard deviation was performed. A two-way repeated measures ANOVA with Bonferroni post-hoc test was used. The Angola demand was between 56–71% maximal HR with [Lac]_PEAK: 6.9±2.9 mM, RPE_PEAK: 10.0±2.2 pts and FS: 2.7±1.7 pts, while in the Benguela participants reached 64–85% maximal HR with [Lac]_PEAK: 9.5±3.0 mM, RPE_PEAK: 11.0±2.8 pts and FS: 2.1±1.6 pts and for São Bento between 69–102% maximal HR with [Lac]_PEAK: 15.7±2.6 mM, RPE_PEAK: 15.5±4.1 pts and FS: -0.8±3.0 pts. Interaction time*performance occurred to [Lac] (F = 42.157; p<0.001), HR (F = 12.154; p<0.001), RRi (F = 4.774; p<0.001), parasympathetic modulation-rMSSD (F = 3.189; p<0.01), [Gluc] (F = 2.152; p<0.05), RPE (F = 5.855; p<0.01), FS (F = 2.448; p<0.05) and PA (F = 3.893; p<0.05). We concluded that São Bento rhythm resulted in a greater physiological demand according to the HR, [Lac] and cardiac autonomic indicators, with the Benguela rhythm being intermediate while the Angola rhythm presented a reduced demand. The [Gluc] increased after the São Bento rhythm when compared to the other rhythms. The perceptual demand presented increased in terms of RPE and PA variables and decreased in terms of FS when the São Bento performance was analyzed in comparison to the Angola and/or Benguela in capoeira.

Double-blind, randomized crossover study of intravenous infusion of magnesium sulfate versus 5% dextrose on depressive symptoms in adults with treatment-resistant depression

AIM

Treatment-resistant depression patients are more likely to suffer from comorbid physical and mental disorders, experience marked and protracted functional impairment, and incur higher health-care costs than non-affected individuals. Magnesium sulfate is a treatment option that may offer great potential for patients with treatment-resistant depression based on prior work in animals and humans.

METHODS

Twelve subjects with mild or moderate treatment-resistant depression were randomized into a double-blind crossover trial to receive an infusion of 4 g of magnesium sulfate in 5% dextrose or placebo infusion of 5% dextrose with a 5-day washout in between the 8-day intervention period. Subjects were assessed before and after the intervention for serum and urine magnesium, lipid panel, the Hamilton Rating Scale for Depression, and the Patient Health Questionnaire-9.

RESULTS

We found a difference in serum magnesium from day 2 to 8 (pre-infusion) (P < 0.002) and from baseline to day 8 (P < 0.02). No changes were noted on the Hamilton Rating Scale for Depression or the Patient Health Questionnaire-9 24 h post-treatment, but as serum magnesium increased from baseline to day 7, the Patient Health Questionnaire-9 decreased from baseline to day 7 (P = 0.02).

CONCLUSION

Magnesium sulfate did not significantly affect depression 24 h post-infusion, but other results were consistent with the literature. The association between changes in serum magnesium and the Patient Health Questionnaire-9 supports the idea that magnesium sulfate may be used to address treatment-resistant depression, an ongoing medical challenge.

Heart Rate and Cardiovascular Responses to Commercial Flights: Relationships with Physical Fitness

The aim of this study was to examine the influence of physical fitness on cardiac autonomic control in passengers prior to, during and following commercial flights. Twenty-two, physically active men (36.4 ± 6.4 years) undertook assessments of physical fitness followed by recordings of 24-h heart rate (HR), heart rate variability (HRV), and blood pressure (BP) on a Control (no flight) and Experimental (flight) day. Recordings were analyzed using a two-way analysis of variance for repeated measures with relationships between variables examined via Pearson product-moment correlation coefficients. Compared to the Control day, 24-h HR was significantly greater (>7%) and HRV measures (5–39%) significantly lower on the Experimental day. During the 1-h flight, HR (24%), and BP (6%) were increased while measures of HRV (26–45%) were reduced. Absolute values of HRV during the Experimental day and relative changes in HRV measures (Control-Experimental) were significantly correlated with measures of aerobic fitness (r = 0.43 to 0.51; −0.53 to −0.52) and body composition (r = −0.63 to −0.43; 0.48–0.61). The current results demonstrated that short-term commercial flying significantly altered cardiovascular function including the reduction of parasympathetic modulations. Further, greater physical fitness and lower body fat composition were associated with greater cardiac autonomic control for passengers during flights. Enhanced physical fitness and leaner body composition may enable passengers to cope better with the cardiovascular stress and high allostatic load associated with air travel for enhanced passenger well-being.

Severe Obesity Shifts Metabolic Thresholds but Does Not Attenuate Aerobic Training Adaptations in Zucker Rats

Severe obesity affects metabolism with potential to influence the lactate and glycemic response to different exercise intensities in untrained and trained rats. Here we evaluated metabolic thresholds and maximal aerobic capacity in rats with severe obesity and lean counterparts at pre- and post-training. Zucker rats (obese: n = 10, lean: n = 10) were submitted to constant treadmill bouts, to determine the maximal lactate steady state, and an incremental treadmill test, to determine the lactate threshold, glycemic threshold and maximal velocity at pre and post 8 weeks of treadmill training. Velocities of the lactate threshold and glycemic threshold agreed with the maximal lactate steady state velocity on most comparisons. The maximal lactate steady state velocity occurred at higher percentage of the maximal velocity in Zucker rats at pre-training than the percentage commonly reported and used for training prescription for other rat strains (i.e., 60%) (obese = 78 ± 9% and lean = 68 ± 5%, P < 0.05 vs. 60%). The maximal lactate steady state velocity and maximal velocity were lower in the obese group at pre-training (P < 0.05 vs. lean), increased in both groups at post-training (P < 0.05 vs. pre), but were still lower in the obese group at post-training (P < 0.05 vs. lean). Training-induced increase in maximal lactate steady state, lactate threshold and glycemic threshold velocities was similar between groups (P > 0.05), whereas increase in maximal velocity was greater in the obese group (P < 0.05 vs. lean). In conclusion, lactate threshold, glycemic threshold and maximal lactate steady state occurred at similar exercise intensity in Zucker rats at pre- and post-training. Severe obesity shifted metabolic thresholds to higher exercise intensity at pre-training, but did not attenuate submaximal and maximal aerobic training adaptations.

Ten weeks of capoeira progressive training improved cardiovascular parameters in male practitioners

BACKGROUND

The present study analyzed the effects of ten weeks of Capoeira progressive training program on the cardiovascular parameters of male practitioners.

METHODS

Participants were assigned into two groups (capoeira, N.=10; 25.4±3.3 years; 24.2±2.2 kg.m2(-1) and Control, N.=08; 29.6±6.3 years; 26.4±4.4 kg.m2(-1)). The Capoeira group performed ten weeks of Capoeira progressive training program, being one session per week lasting 90 minutes each. The control group was instructed to avoid any exercise training program or intense physical activities during the experimental period. The blood pressure (BP), heart rate (HR), and rate pressure product (RPP), as well as HR variability (HRV) indicators were evaluated on resting, before and after intervention.

RESULTS

A two-way ANOVA revealed a main effect of group by time interaction to HR (F=6.649, η2=0.379; P=0.02), and HRV indicators (RRi: F=5.752, η2=0.313; rMSSD: F=4.652, η2=0.283; SD1: F=4.694, η2=0.409, and pNN50: F=5.561, η2=0.360; P<0.05). A main effect of time condition was verified for capoeira group (P<0.05) on HR (∆=-6.6±6.0 bpm), RRi (∆=80.1±65.4 ms), rMSSD (∆=14.1±11.6 ms), SD1 (∆=10.0±8.2 ms), and pNN50 (∆=11.3±9.7%). The between groups analysis identified significant differences (P<0.05) for the HR after intervention (capoeira: -8.6±6.9% vs.

CONTROL

-0.7±3.9%). The comparison between capoeira vs. control for HRV indicators (RRi: ∆=10.1±8.5% vs. 0.9±7.6%; rMSSD: ∆=37.8±32.9% vs. 2.9±31.3%; pNN50: ∆=96.2±78.7% vs. 0.3±54.1%; and SD1: ∆=37.7±32.9% vs. 6.5±24.4%; respectively) differed to each other (P<0.05).

CONCLUSIONS

Our findings showed that ten weeks of capoeira progressive training program improves both autonomic and cardiovascular parameters in male practitioners.

The effect of exercise training on disease progression, fitness, quality of life, and mental health in people living with HIV on antiretroviral therapy: a systematic review

BACKGROUND

Exercise has been associated with improvements in adverse physiological and psychological effects of long-term antiretroviral therapy (ART) in people living with HIV (PLWH).

AIM

To summarizes the findings on the effects of aerobic or resistance training alone or combined aerobic and resistance exercise training (CARET) on disease progression, fitness, physical functioning, mental health, and quality of life (QOL) in PLWH receiving ART. A systematic search of articles was performed in several databases, and 20 articles that met inclusion criteria were summarized.

RELEVANCE FOR PATIENTS

Aerobic exercise was associated with improvements in aerobic capacity, QOL, and depressive symptoms, while resistance training improved strength. CARET was related to improved aerobic fitness, strength, physical functioning, QOL, and self-efficacy. At least one of the exercise interventions resulted in improvements in CD4+ cell count and HIV RNA viral load. Moreover, another study showed that HIV-specific biomarkers remained unchanged in the exercise intervention group, while they significantly worsened in the non-exercise group. In general, in spite of their well-known benefits, exercise programs have not been extensively utilized or widely recognized as viable therapeutic treatment options for this patient population. Knowing the possible health benefits of increasing physical activity level is important to better recommend exercise programs. However, the prescription must be done carefully and on an individual basis. Additional studies investigating the efficiency and effectiveness of different exercise training regimens for PLWH are needed.

Does whole-body cryotherapy improve vertical jump recovery following a high-intensity exercise bout?

Whole-body cryotherapy (WBC) has been used as a recovery strategy following different sports activities. Thus, the aim of the study reported here was to examine the effect of WBC on vertical jump recovery following a high-intensity exercise (HIE) bout. Twelve trained men (mean ± standard deviation age = 23.9±5.9 years) were randomly exposed to two different conditions separated by 7 days: 1) WBC (3 minutes of WBC at -110°C immediately after the HIE) and 2) control (CON; no WBC after the HIE). The HIE consisted of six sets of ten repetitions of knee extensions at 60° · s(-1) concentric and 180° · s(-1) eccentric on an isokinetic dynamometer. The vertical jump test was used to evaluate the influence of HIE on lower extremity muscular performance. The vertical jump was performed on a force platform before HIE (T1) and 30 minutes after (T2) the WBC and CON conditions. As a result of HIE, jump height, muscle power, and maximal velocity (Vmax) had significant decreases between T1 and T2, however no significance was found between the WBC and CON conditions. The results indicate that one session of WBC had no effect on vertical jump following an HIE compared with a CON condition. WBC may not improve muscle-function (dependent on stretch-shortening cycle) recovery in very short periods (ie, 30 minutes) following HIE.

Traditional games resulted in post-exercise hypotension and a lower cardiovascular response to the cold pressor test in healthy children

The present study aimed to verify if blood pressure (BP) reactivity could be reduced through a previous single session of active playing when compared to sedentary leisure. Sixteen pre-pubertal healthy children participated in this study. After familiarization with procedures and anthropometric evaluation, participants performed three sessions in randomized order: (1) 30 min of traditional Brazilian games (PLAY); (2) 30 min of video game playing (DDR); and (3) 30 min of watching TV (TV). Each session lasted 80 min, being 10 min of rest; 30 min of intervention activity; and 40 min of recovery. After recovery, the Cold Pressor Test (CPT) was used for the assessment of acute cardiovascular reactivity. BP was recorded at 30 s and 1 min during the CPT. Analysis of variance showed post-exercise hypotension (PEH) only after PLAY, and that systolic and diastolic BP were significantly increased in all conditions during CPT. However, the magnitude of the CPT-induced BP response was significantly less in PLAY compared to DDR and TV. The PEH observed during recovery and the reduced BP response to CPT following playing traditional games may be due its higher cardiovascular and metabolic demand as was indicated by the increased heart rate, oxygen consumption, and BP. It was concluded that BP reactivity to stress may be reduced through a previous single session of traditional games and that PEH was recorded only after this exercise form. This benefit indicates a potential role of playing strategies for cardiovascular health in childhood.

Combined exercise circuit session acutely attenuates stress-induced blood pressure reactivity in healthy adults

Objective

To investigate the blood pressure (BP) responses to cardiovascular stress test after a combined exercise circuit session at moderate intensity.

Method

Twenty individuals (10 male/10 fem; 33.4± 6.9 years; 70.2± 15.8 kg; 170.4± 11.5 cm; 22.3± 6.8% body fat) were randomized in a different days to control session with no exercise or exercise session consisting of 3 laps of the following circuit: knee extension, bench press, knee flexion, rowing in the prone position, squats, shoulder press, and 5 min of aerobic exercise at 75-85% of age-predicted maximum heart rate and/or 13 on the Borg Rating of Perceived Exertion [scale of 6 to 20]. The sets of resistance exercise consisted of 15 repetitions at ~50% of the estimated 1 repetition maximum test. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured at rest and during 1h of recovery in both experimental sessions. After that, blood pressure reactivity (BP_R) was evaluated using the Cold Pressor Test.

Results

During 1h of exercise recovery, there was a reduction in SBP (3-6 mmHg) and DBP (2-5 mmHg) in relation to pre-session rest (p<0.01), while this reduction was not observed in the control session. A decline in BP_R (4-7 mmHg; p<0.01) was observed 1h post-exercise session, but not in the control session. Post-exercise reductions in SBP and DBP were significantly correlated with BP_R reductions (r=0.50-0.45; p<0.05).

Conclusion

A combined exercise circuit session at moderate intensity promoted subsequent post-exercise hypotension and acutely attenuated BP_R in response to a cardiovascular stress test. In addition, the post-exercise BP reduction was correlated with BP_R attenuation in healthy adults of both genders.

Effects of acute exercise over heart proteome from monogenic obese (ob/ob) mice

Exercise is recognized to prevent and attenuate several metabolic and cardiovascular disorders. Obesity is commonly related to cardiovascular diseases, frequently resulting in heart failure and death. To elucidate the effects of acute exercise in heart tissue from obese animals, 12-week-old C57BL6/J obese (ob/ob) and non-obese (ob/OB) mice were submitted to a single bout of swimming and had their hearts analyzed by proteomic techniques. Mice were divided into three groups: control (ob/ob, n = 3; ob/OB, n = 3); a moderate intensity consisting of 20 min of swimming around 90% of Maximal Lactate Steady State (ob/ob, n = 3; ob/OB, n = 3), and a high intensity exercise performed as an incremental overload test (ob/ob, n = 3; ob/OB, n = 3). Obesity modulations were analyzed by comparing ob/ob and ob/OB control groups. Differential 2-DE analysis revealed that single session of exercise was able to up-regulate: myoglobin (ob/ob), aspartate aminotransferase (ob/OB) and zinc finger protein (ob/OB) and down-regulate: nucleoside diphosphate kinase B (ob/OB), mitochondrial aconitase (ob/ob and ob/OB) and fatty acid binding protein (ob/ob). Zinc finger protein and α-actin were up-regulated by the effect of obesity on heart proteome. These data demonstrate the immediate response of metabolic and stress-related proteins after exercise so as contractile protein by obesity modulation on heart proteome.

Blood glucose control for individuals with type-2 diabetes: acute effects of resistance exercise of lower cardiovascular-metabolic stress

This study compared the effects of resistance exercise (RE) intensities on blood glucose (GLUC) of individuals without (ND) and with type-2 diabetes (T2D). Nine individuals with T2D and 10 ND performed: (a) RE circuit at 23% of 1 maximal repetition (1RM) (RE_L); (b) RE circuit at 43% 1RM (RE_M); and (c) control (CON) session. Blood lactate (LAC) and GLUC were measured before, during, and postinterventions. Double product (DP) and rate of perceived exertion (RPE) were recorded. The area under the curve (AUC) revealed the effects of RE circuits in reducing GLUC in individuals with T2D (RE_L: 12,556 ± 3,269 vs. RE_M: 13,433 ± 3,054 vs. CON: 14,576 ± 3,922 mg.dl(-1).145 minutes; p < 0.05) with a lower AUC of GLUC in RE_L in comparison to RE_M. Similarly, for ND the RE_L reduced the AUC of GLUC when compared with RE_M and CON (RE_L: 10,943 ± 956 vs. RE_M: 12,156 ± 1,062 vs. CON: 11,498 ± 882 mg.dl(-1).145 minutes; p < 0.05). The AUC of GLUC was higher for T2D compared with ND on CON condition (p = 0.02). However, after RE circuits the difference between groups for AUC of GLUC was abolished. The RE_M for T2D was more stressful when compared with RE_L for LAC (CON: 1.3 ± 0.5 vs. RE_L: 5.5 ± 1.5 vs. RE_M: 6.8 ± 1.3 mmol·L(-1); p < 0.05), DP (CON: 8,415 ± 1,223 vs. RE_L: 15,980 ± 2,007 vs. RE_M: 18,047 ± 3,693 mmHg.bpm(-1); p < 0.05), and RPE (RE_L: 11 ± 2 vs. RE_M: 13 ± 2 Borg Scale; p < 0.05). We concluded that RE_L and RE_M were effective in reducing GLUC for individuals with T2D, with lower cardiovascular-metabolic and perceptual stress being observed for RE_L. These data suggest that acute RE sessions at light or moderate intensities are effective for controlling GLUC in individuals with T2D.

Physiological and perceived exertion responses at intermittent critical power and intermittent maximal lactate steady state

The aim of this study was to compare the power outputs of the intermittent critical power (CPi) with the intermittent maximal lactate steady state (MLSSi) and to compare the physiological and perceptual responses exercising at CPi and MLSSi. Ten subjects performed intermittent trials on a cycle ergometer to determine CPi and MLSSi using 30:30 seconds of effort and pause. The oxygen uptake (&OV0312;o2), heart rate (HR), blood lactate concentration ([Lac]), and rating of perceived exertion (RPE) responses were compared during 30-minute cycling at CPi and MLSSi. The CPi (267 ± 45 W) was similar to MLSSi (254 ± 39 W), and they were correlated (r = 0.88; p < 0.05). The &OV0312;o2 and HR responses stabilized throughout exercising at CPi (2.52 ± 0.52 L·min; 156 ± 8 b·min) and MLSSi (2.41 ± 0.32 L·min; 152 ± 10 b·min). These physiological variables were similar between conditions. However, the [Lac] and RPE were higher from the middle to the end of exercise duration at CPi ([Lac] = 6.9 ± 2.6 mM; RPE = 17.1 ± 2.1 a.u.) compared to MLSSi ([Lac] = 5.1 ± 0.9 mM; RPE = 15.7 ± 1.8 a.u.). Therefore, CPi intensity determined from 30:30 seconds of effort and rest periods on a cycle ergometer is equivalent to the MLSSi, and there is a physiological steady state throughout both exercise intensities, although the [Lac] and RPE responses at CPi are higher than at MLSSi. Thus, the CPi and MLSSi may be used as tools for intermittent training evaluation and prescription.

Noninvasive method to estimate anaerobic threshold in individuals with type 2 diabetes

BACKGROUND

While several studies have identified the anaerobic threshold (AT) through the responses of blood lactate, ventilation and blood glucose others have suggested the response of the heart rate variability (HRV) as a method to identify the AT in young healthy individuals. However, the validity of HRV in estimating the lactate threshold (LT) and ventilatory threshold (VT) for individuals with type 2 diabetes (T2D) has not been investigated yet.

AIM

To analyze the possibility of identifying the heart rate variability threshold (HRVT) by considering the responses of parasympathetic indicators during incremental exercise test in type 2 diabetics subjects (T2D) and non diabetics individuals (ND).

METHODS

Nine T2D (55.6 ± 5.7 years, 83.4 ± 26.6 kg, 30.9 ± 5.2 kg.m2(-1)) and ten ND (50.8 ± 5.1 years, 76.2 ± 14.3 kg, 26.5 ± 3.8 kg.m2(-1)) underwent to an incremental exercise test (IT) on a cycle ergometer. Heart rate (HR), rate of perceived exertion (RPE), blood lactate and expired gas concentrations were measured at the end of each stage. HRVT was identified through the responses of root mean square successive difference between adjacent R-R intervals (RMSSD) and standard deviation of instantaneous beat-to-beat R-R interval variability (SD1) by considering the last 60 s of each incremental stage, and were known as HRVT by RMSSD and SD1 (HRVT-RMSSD and HRVT-SD1), respectively.

RESULTS

No differences were observed within groups for the exercise intensities corresponding to LT, VT, HRVT-RMSSD and HHVT-SD1. Furthermore, a strong relationship were verified among the studied parameters both for T2D (r = 0.68 to 0.87) and ND (r = 0.91 to 0.98) and the Bland & Altman technique confirmed the agreement among them.

CONCLUSION

The HRVT identification by the proposed autonomic indicators (SD1 and RMSSD) were demonstrated to be valid to estimate the LT and VT for both T2D and ND.

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.

Physiological responses to a tap dance choreography: comparisons with graded exercise test and prescription recommendations

The aim of this study was to analyze the physiological responses to a tap dance choreography and to compare with those observed during a maximal treadmill exercise test, in tap dancers. Eight women (19.6 +/- 2.4 years; 162.3 +/- 4.4 cm; 54.0 +/- 2.3 kg; 20.5 +/- 1.4 kg.m; and 5.1 +/- 2.6 years of tap dance training) were submitted to the following procedures: (a) graded exercise test (GXT) on a treadmill until volitional exhaustion with 0.8 km.h of increment at each 3 and 1 minute of interval between stages and (b) tap dance choreography (TAP)-"The Shim Sham Shimmy"-consisting of 9 stages of 3 minutes with 1-minute rest between stages. Expired gas analyses were performed in all experimental sessions, providing breath-by-breath values for respiratory exchange rate (RER), oxygen uptake (VO(2)), and carbon dioxide production (CO2). Heart rate (HR) and rate of perceived exertion (RPE) were also measured. During the rest period between stages, blood samples (25 microl) were collected from the ear lobe for lactate threshold (LT) determination. It was observed that at the end of the TAP, subjects achieved an average of 83.8 +/- 6.2% of the HRmax and 68.9 +/- 11.3% of the VO(2)max, both previously identified in the GXT. The choreography demanded 204.7 +/- 31.3 kcal, an average RER of 0.88 +/- 0.05 and mean RPE of 13 +/- 2. The VO(2), HR, and RPE values did not significantly differ from those at the LT intensity identified during the GTX. Based on the present results, it was concluded that the TAP performance in the "The Shim Sham Shimmy" choreography elicited acute physiologic responses similar to those observed at the LT intensity, thus suggesting that Tap Dance constitutes a useful exercise modality for aerobic fitness and cardiovascular health improvements.

[Methods to identify the anaerobic threshold for type-2 diabetic and non-diabetic subjects]

BACKGROUND

In spite of Anaerobic Threshold (AT) to be widely used on exercise evaluation for different populations, there are few studies comparing methods to identify AT for individuals with type-2 diabetes.

OBJECTIVE

To compare methods of AT determination on type-2 diabetics (T2D) and non-diabetic (ND) subjects and verify the acid-base balance as related to AT intensity.

METHODS

T2D (n=10; 54.5+/-9.5 yr; 30.1+/-5.0 kg/m(2)) and younger ND (n=10; 36.6+/-12.8 yr; 23.9+/-5.0 kg/m(2)) performed an incremental test (IT) on a cycle ergometer. The over-proportional increase in VE/VO2 and blood lactate ([lac]) identified the ventilatory (VT) and lactate thresholds (LT) respectively. The workload corresponding to the lower blood glucose ([gluc]) during test identified the individual glucose threshold (IGT). The AT was also determined by polynomial adjustment of the VE/Workload and [lac]/Workload responses to identify exercise intensities above which an over-proportional increase in VE and [lac] did occur and were named VT VE/W and LT[lac]/W.

RESULTS

The workload (Watts-W) corresponding to LT, VT, IGT, LT Lac/W and VT VE/W of diabetics (85.0+/-32.1; 88.0+/-31.7; 86.0+/-33.8; 82.0+/-20.9 and 90.2+/-22.2W) and non-diabetics (139.0+/-39.0; 133.0+/-42.7; 140.8+/-36.4; 122.7+/-44.3 and 133.0+/-39.1W) differed between groups (p<0.001), but not within groups. Thus it was evidenced an agreement among the studied methods. The pH and pCO2 were significantly decreased in parallel to the increase in [lac], pO2 and VE at supra AT intensities.

CONCLUSION

The AT intensities, as determined by different methods both for diabetics and non-diabetic individuals, were in agreement to each other and identified exercise intensities above which the acid-basic balance is disrupted.

Postresistance exercise blood pressure reduction is influenced by exercise intensity in type-2 diabetic and nondiabetic individuals

This study analyzed the postexercise blood pressure (BP) after resistance exercise (RE) on middle-aged type-2 diabetic (T2DM, n = 10, 46.6 +/- 13.1 years) and nondiabetic subjects (NDM, n = 10, 52.0 +/- 13.2 years). Participants performed (a) 1 repetition maximum (1RM) strength test; (b) 3 laps in an RE circuit of 6 exercises (16 repetitions at 43% 1RM); (c) 3 laps in an RE circuit (30 repetitions at 23% 1RM); and (d) a control session. The blood lactate concentration ([lac]) (YSI 2700S) and BP (Microlife BP3AC1-1) were measured pre-exercise, after exercise, and at each 15 minutes during the 120 minutes of recovery. Analysis of variance with Bonferroni as a post hoc evidenced that the 43% 1RM session elicited the highest [lac] response for both NDM (7.8 +/- 1.8 vs. 6.4 +/- 1.8 mmol x L(-1); p < 0.05) and T2DM (7.0 +/- 1.4 vs. 5.6 +/- 1.6 mmol x L(-1); p < 0.05). Also, the 43% 1RM session promoted a significant postexercise hypotension (PEH) of systolic blood pressure (SBP) and mean arterial pressure (MAP), whereas the 23% 1RM did not. The highest BP reductions for T2DM and NDM after 43% 1RM were, respectively, 9.5 +/- 11.1 and 11.0 +/- 7.1 mmHg for SBP and 6.4 +/- 7.8 and 7.7 +/- 7.9 mmHg for the MAP (p <or= 0.05). The PEH of SBP lasted longer (120 minutes) for NDM than for T2DM (90 minutes). The PEH may be associated with [lac] elevation, and the lower hypotensive effect presented by T2DM may be related to endothelial dysfunction usually observed in diabetic individuals. In conclusion, the RE of higher intensity, performed in approximately 25-minute duration, was more efficient at promoting PEH which, in turn, suggests its use on BP control for middle-aged T2DM and NDM subjects with characteristics similar to those of our participants.

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.

Estimating the perceived exertion threshold using the OMNI scale

This study aimed to determine if the OMNI scale with cycle ergometer pictorial format can be used to estimate perceived exertion threshold (PETOMNI) and nonexhaustive PET (PETOMNI5-8) and to compare and to correlate these PET estimates with PETBorg, PETBorg14-17, and critical power (CP). During different days, 13 men performed 4 different high-intensity constant-loads work bouts until exhaustion on a cycle ergometer using the Borg scale, whereas the OMNI scale was used during the other 4 work bouts using previous constant loads. The PET for both scales was determined by plotting the increasing rates of perceived exertion against power outputs, PET being the intersection point of the regression line. In addition, a hyperbolic relationship between power and time to exhaustion was used to determine CP. The PETOMNI (183+/-36 W) was similar to PETBorg (178+/-46 W), and they were also significantly correlated (r=0.77). The PETOMNI5-8 (175+/-36 W) was similar to PETBorg14-17 (181+/-38 W); however, they were not significantly correlated (r=0.36). All the PET estimates were similar to CPOMNI (167+/-36 W) and CPBorg (169+/-40 W) and also significantly correlated (r=0.79-0.94), excepting PETOMNI5-8 (r=0.46). In conclusion, OMNI cycling scale can be used to estimate PET and CP with high accuracy. However, the nonexhaustive PET derived from the 5-8 range in the OMNI scale did not provide a valid estimate of maximal sustainable power output because of the absence of correlation with PETBorg14-17 and with CP. Therefore, professionals and practitioners can assess the subjects' aerobic fitness through the PET estimation using the OMNI scale during exhaustive tests.

Effects of treadmill running and resistance exercises on lowering blood pressure during the daily work of hypertensive subjects

The purposes of this study were to compare the hypotensive effects of treadmill running (TR) and resistance exercise (RE) performed by hypertensive subjects and to verify if the hypotensive effects of these exercises are maintained during a regular white-collar workday. Fifteen white-collar workers (42.9 +/- 1.6 years), treated with antihypertensive medication, accomplished three different sessions: 20 minutes of TR (approximately 70-80% of heart rate reserve), 20 minutes of circuit training RE (20 repetitions at 40% of 1 repetition maximum), and a control session without exercise (CON). The systolic blood pressure (BP), diastolic BP, heart rate, and blood lactate were measured at resting (Rest) and after sessions at 15th (R15), 30th (R30), 45th (R45), and 60th (R60) min, as well as after lunch (AL), four (R4h) and seven (R7h) hours of recovery at the participants' workplace. In relation to rest, a higher decrease of systolic BP after TR (-11.1 +/- 7.6 mm Hg) and RE (-12.6 +/- 7.3 mm Hg) was observed respectively at the R30 and R45. For diastolic BP, the highest decreases after TR (-4.0 +/- 6.4 mm Hg) and RE (-9.0 +/- 7.0 mm Hg) were observed respectively at the R45 and R30. The systolic BP and mean BP after TR and RE differed significantly from CON session (p < 0.05), and lower post-exercise values could be observed over the workday. In conclusion, both 20 minutes of TR and RE resulted in postexercise hypotension, and were able to reduce BP throughout 7 hours after exercise, even throughout the subject's regular occupational activities. Also, the RE promoted higher cardiac protection and can be a useful model of physical exercise prescription for hypertension individuals.

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.

Methods to identify the lactate and glucose thresholds during resistance exercise for individuals with type 2 diabetes

The purpose of this study was to compare different methods to identify the lactate threshold (LT) and glucose threshold (GT) on resistance exercise for individuals with type 2 diabetes. Nine men with type 2 diabetes (47.2 +/- 12.4 years, 87.6 +/- 20.0 kg, 174.9 +/- 5.9 cm, and 22.4 +/- 7.2% body fat) performed incremental tests (ITs) on the leg press (LP) and bench press (BP) at relative intensities of 10, 20, 25, 30, 35, 40, 50, 60, 70, 80, and 90% of one-repetition maximum (1RM) at each 1-minute stage. During the 2-minute interval between stages, 25 mul of capillary blood were collected from the earlobe for blood lactate [Lac] and blood glucose [Gluc] analysis (YSI 2700S). The LT in the LP and BP was identified at IT by the inflexion in [Lac] response as well as by an equation originated from a polynomial adjustment (LTp) of the [Lac]/% 1RM ratio responses. The lowest [Gluc] during the IT identified the GT. The analysis of variance did not show differences among the 1RM at the thresholds identified by different methods in the LP (LTLP = 31.0% +/- 5.3% 1RM; GTLP = 32.1% +/- 6.1% 1RM; LTpLP = 36.7% +/- 5.6% 1RM; p > 0.05) and BP (LTBP = 29.9% +/- 8.5% 1RM; GTBP = 32.1% +/- 8.5% 1RM; LTpBP = 31.8% +/- 6.7% 1RM; p > 0.05). It was concluded that it was possible to identify the LT and GT in resistance exercise by different methods for individuals with type 2 diabetes with no differences between them. The intensities (kg) corresponding to these thresholds were between 46% and 60% of the body weight on the LP and between 18% and 26% of the body weight on the BP, in which the exercise prescription would be done to this intensity in 3 sets of 20 to 30 repetitions each and 1 minute of rest while alternating the muscle groups for blood glucose control for individuals with characteristics similar to the participants.

Hypotensive effects of exercise performed around anaerobic threshold in type 2 diabetic patients

AIM

To verify the occurrence of post-exercise hypotension (PEH) in type 2 diabetics (DM(2)) and the effects of exercise intensity on post-exercise blood pressure (BP).

METHODS

Eleven men and women with DM(2) (58.5+/-10.2 years; 160+/-0.1cm; 80.6+/-13.5kg; 31.2+/-3.8kg/m(2), 19+/-3.2mLkgmin(-1) of VO(2max), 155.0+/-39.2mgdL(-1) of fasting blood glucose and 126+/-10/75+/-7mmHg of resting BP) performed an incremental test (IT) for cardiovascular evaluation and anaerobic threshold (AT) determination. Then, participants randomly underwent 2 exercise sessions (90% and 110% AT) and a control session (CON). In all sessions, BP was measured at resting, during 20min of exercise/control and at each 15min through 120min of post-exercise recovery (R15-R120).

RESULTS

The mean results of systolic BP (SBP)/diastolic BP (DBP) over the 120min of recovery were 125+/-16/76+/-7mmHg, 122+/-13/75+/-6mmHg and 129+/-16/78+/-7mmHg, respectively for 90%, 110% and CON. Significant reductions of SBP occurred after 90% (R15-R45) and 110% (R15-R90), while only after 110% there were reductions of DBP (R15, R45) and MAP (R15, R45, R75, R90, R105).

CONCLUSIONS

Both exercise intensities evoked reductions in SBP while DBP and MAP were reduced only after 110%. Despite the higher intensity exercise to be more effective in promoting BP reductions, we suggest caution while prescribing exercise for DM(2).

Predicting insulin resistance in children: anthropometric and metabolic indicators

OBJECTIVE

To predict insulin resistance in children based on anthropometric and metabolic indicators by analyzing the sensitivity and specificity of different cutoff points.

METHODS

A cross-sectional study was carried out of 109 children aged 7 to 11 years, 55 of whom were obese, 23 overweight and 31 well-nourished, classified by body mass index (BMI) for age. Measurements were taken to determine BMI, waist and hips circumferences, waist circumference/hip circumference ratio, conicity index and body fat percentage (dual emission X-ray absorptiometry). Fasting blood samples were taken to measure triglyceridemia, glycemia and insulinemia. Insulin resistance was evaluated by the glycemic homeostasis method, taking the 90th percentile as the cutoff point. Receiver operating characteristic curves were analyzed to a 95% confidence interval in order to identify predictors of glycemic homeostasis, and sensitivity and specificity were then calculated.

RESULTS

After analysis of the area under the receiver operating characteristic curve (confidence interval), indicators that demonstrated the power to predict insulin resistance were, in the following order: insulinemia = 0.99 (0.99-1.00), 18.7 microU mL(-1); body fat percentage = 0.88 (0.81-0.95), 41.3%; BMI = 0.90 (0.83-0.97), 23.69 kg m(2-(1)); waist circumference= 0.88 (0.79-0.96), 78.0 cm; glycemia = 0.71 (0.54-0.88), 88.0 mg dL(-1); triglyceridemia = 0.78 (0.66-0.90), 116.0 mg dL(-1) and conicity index = 0.69 (0.50-0.87), 1.23 for the whole sample; and were: insulinemia = 0.99 (0.98-1.00), 19.54 microU mL(-1); body fat percentage = 0.76 (0.64-0.89), 42.2%; BMI = 0.78 (0.64-0.92), 24.53 kg m(2-(1)); waist circumference = 0.77 (0.61-0.92), 79.0 cm and triglyceridemia = 0.72 (0.56-0.87), 127.0 mg dL(-1), for the obese subgroup.

CONCLUSIONS

Anthropometric and metabolic indicators appear to offer good predictive power for insulin resistance in children between 7 and 11 years old, employing the cutoff points with the best balance between sensitivity and specificity of the predictive technique.

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)<CV (292.1+/-17.5)=V10km (291.7+/-19.3)<V(HRd) (300.8+/-18.7)=V3000 (304+/-17.5) with high correlation among parameters (P<0.001). During ETVlm participants completed 30 min of running while on the ETV(HRd) they lasted only 12.5+/-8.2 min with increasing [lac].

CONCLUSIONS

We evidenced that CV and Vlm track-protocols are valid for running evaluation and performance prediction and the parameters studied have different significance. The V(lm) reflects the moderate-high intensity domain (below CV), can be sustained without [lac] accumulation and may be used for long-term exercise while the V(HRd)overestimates a running intensity that can be sustained for long-time. Additionally, V3000 and V(HRd) reflect the severe intensity domain (above CV).

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).