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Results: The area under the curve (AUC) evidenced a significant effect of RE on reducing GLUC (mg.dL-1x145min) for 23%1RM (T2D ±3268.9; NT2D - 10942.7±955.8) and 43%1RM (T2D - 13432.9±3054.4; NT2D -12156.2±1062.0) vs. Control (T2D - 14576.4±3922.2;
NT2D -11498.2±881.9), p0.05 for the intensities and among T2D e NT2D in control. Although that, the 43%1RM was more stressful than 23%1RM session (p0.05) in both groups for LAC (T2D - 542.2±143.5 vs. 432.8±126.2 and NT2D - 615.0±148.7 vs. 479.0±144.1), RPP (T2D ±302358.8 vs. 1582176.0±188382.5 and NT2D - 1625613.3±295464.4 vs. 1506175.6±239996.0) and RPE (T2D - 384.7±64.6 vs.
323.9±62.5 and NT2D - 419.8±56.8 vs. 338.9±23.3).
Discussion: Resistance training for T2D is important for improvement of glycemic control, insulin sensitivity and muscular strength (Gordon, 2009). And one single session can provide transient improvements in glucose capitation. Our findings suggest that resistance exercise sessions performed at light and moderate intensities were effective on reducing blood glucose for T2D, with the 23%1RM session presenting a lower metabolic, hemodynamic and perceptual stresses.
References Albright A, Franz M, Hornsby G, et al. (2000). Med Sci Sports Exerc 32(7), 1345-1360.
Gordon BA, Benson AC, Bird SR, Fraser SF. (2209). Diabetes Res Clin Pract 83 (2), 157-175.
INTRA-ARTERIAL BLOOD PRESSURE RESPONSE DURING RESISTANCE EXERCISE OF DIFFERENT INTENSITIES IN HYPERTENSIVES TREATED WITH ATENOLOLFORJAZ, C.L.M., GOMIDES, R.S., SOUZA, D.R., COSTA, L.A.R., ORTEGA, K.C., FERNANDES, J.R.C., TINUCCI, T., MION JR, D.
UNIVERSITY OF SÃO PAULOIntroduction: Dynamic resistance exercise is recommended in association to aerobic exercise for hypertensive patients. Blood pressure increase during this kind of exercise is mainly due to an increase in peripheral vascular resistance; however, an increase in cardiac output might also be involved. This blood pressure increase seems to be exacerbated in non-medicated hypertensives when compared with normotensives. Nevertheless, most of the hypertensives are taking medications, and some of them are receiving β-blockers, which decreases cardiac output by the inhibition of sympathetic-induced increase on heart rate and cardiac contractility. Thus, βblockers might decrease blood pressure rise during resistance exercise which, to our knowledge, has not been studied yet. Hence, the aim of this study was to verify the effects of the selective β-blocker atenolol on blood pressure increase during dynamic resistance exercise of different intensities.
Methods: Ten essential hypertensives with systolic/diastolic blood pressures under placebo condition maintained between 140 and 160 / 90 and 105 mmHg were recruited. These volunteers were studied after 6 weeks of placebo and atenolol treatment, and they were blinded for the medication used. In each phase, the volunteers executed, in a random order, 3 protocols of knee extension exercise until fatigue: a) 1 set at 100% of 1 repetition maximum (1RM); b) 3 sets at 40% of 1RM; and c) 3 sets at 80% of 1RM. Before, during and after the exercises, intra-arterial radial blood pressure was measured. Data were compared by paired student t-test and by two-way ANOVA for repeated measures. Newman-Keuls post-hoc test was applied when necessary. P≤0.05 was considered as significant.
Results: Atenolol decreased the absolute value achieved by systolic blood pressure during the exercise performed at the 3 intensities (maximum values: 100% = 186±4 vs. 215±7, 80%= 224±7 vs. 247±9 and 40% = 223±7 vs. 252±16, mmHg, P≤0.05). Moreover, atenolol also reduced systolic blood pressure increase in the first set of exercise at the 3 intensities (100% = +38±5 vs. +54±9; 80% = +68±11 vs. +84±13 and 40% = +69±7 vs. +84±14, mmHg, P≤0.05). In regard to diastolic blood pressure, atenolol decreased its
14 ANNUAL CONGRESS OF THE EUROPEAN COLLEGE OF SPORT SCIENCETH Wednesday, June 24th, 2009 absolute values and its increase during exercise performed at 100% of 1RM (126±6 vs. 145±6 and +41±6 vs. +52±6, mmHg, P≤0.05), but it did not change diastolic blood pressure response at the other exercise intensities.
Atenolol therapy was effective in reducing both systolic blood pressure absolute values and increase during resistance exercise of different intensities in hypertensive subjects; given them some cardiovascular protection. This result supports the hypothesis that cardiac output increase is important for blood pressure enhancement during this kind of exercise.
Financial support: FAPESP
EFFECTS OF SHORT-TERM BODY-WEIGHT SUPPORTED TREADMILL TRAINING AND HEAD-UP TILT TRAINING ON HEART
RATE DYNAMICS IN INDIVIDUALS WITH SPINAL CORD INJURYMILLAR, P., RAKOBOWCHUK, M., ADAMS, M., HICKS, A., MCCARTNEY, N., MACDONALD, M.
MCMASTER UNIVERSITYIncreased risk of cardiovascular disease and autonomic disregulation are common health concerns in individuals with spinal cord injury (SCI) (Krassioukov and Claydon, 2006). Body-weight supported treadmill training (BWSTT) and head-up tilt training (HUTT) are two interventions that may help improve cardiovascular control in individuals with SCI. BWSTT has been shown to improve linear heart rate variability after 6 months of training in participants with SCI (Ditor et al., 2005), however, the effects of short-term training remain unknown. The purpose of this study was to compare the effects of short-term BWSTT and HUTT on neurocardiac regulation in SCI. Seven participants (6♂, 37.1 ± 7.7 yrs [mean ± SEM]) with SCI (lesion level: C5-T10, ASIA score: A-C; 5.0 ± 4.4 yrs post-injury) completed 4 wks of thriceweekly BWSTT and HUTT (i.e. 12 sessions each), applied in a randomized, cross-over design, and separated by a 4 wk detraining period.
Cardiac autonomic modulation was indirectly assessed at rest, before and after, each 4 wk training period using linear heart rate variability and non-linear (sample entropy and detrended fluctuation analysis (α1)) measures of heart rate dynamics. Participants completed equal amounts of BWSTT and HUTT (453.7 ± 27.3 min vs. 471.6 ± 19.7 min, p=0.24). There were no significant changes in any time or frequency indices of linear heart rate variability following either BWSTT or HUTT (p0.05). A significant interaction effect (group x time) was detected for sample entropy as values increased following BWSTT (1.05 ± 0.14 to 1.57 ± 0.13, p0.05) but not HUTT (1.36 ± 0.11 to 1.37 ± 0.17, p0.05). The short-term scaling exponent (α1) exhibited a significant main effect for time (1.32 ± 0.10 to 1.17 ± 0.09, p=0.02), demonstrating an overall reduction following all training interventions. Due to the potential bidirectional responses of α1 we calculated a distance score from the value 1, which reflects healthy heart rate dynamics (Heffernan et al., 2008), defined as│1 – α1│. Following this calculation, a significant interaction effect was detected as BWSTT reduced the distance score (0.54 ± 0.06 to 0.26 ± 0.05, p=0.001), while no change was found after HUTT (0.36 ± 0.08 to 0.39 ± 0.09, p0.05). In conclusion, 4 wks of BWSTT are sufficient to improve sample entropy and α1, but not traditional measures of linear heart rate variability. These improvements may reflect improved cardiac vagal modulation following short-term BWSTT. Further investigation is required to detail the potential effects of dynamic and passive training interventions on modulating non-linear heart rate dynamics in patients with SCI.
Ditor DS, Kamath MV, MacDonald MJ, Bugaresti J, McCartney N, Hicks AL (2005). J Appl Physiol 98, 1519-1525.
Heffernan KS, Sosnoff JJ, Fahs CA, Shinsako KK, Jae SY, Fernhall B. (2008). J Appl Physiol 105, 109-113.
Krassioukov AV, Claydon VE (2006). Prog Brain Res 152, 223–229.
13:00 - 14:00 Poster presentations PP-PH04 Physiology 4
DECREASE IN HEART RATE AFTER LONGITUDINAL PARTICIPATION IN THE GRONINGEN ACTIVE LIVING MODEL (GALM)
RECREATIONAL SPORTS PROGRAMDE JONG, J.
HANZE UNIVERSITY OF APPLIED SCIENCES GRONINGENObjective: To investigate changes in heart rate during submaximal exercise as an index of cardiovascular function in older adults participating in the GALM recreational sports program who were sedentary or underactive at baseline.
Methods: A repeated measurement design was conducted; 151 participants were included, providing 398 heart rate files over a period of 18 months of GALM. Multilevel analyses were conducted; growth and final models containing a time variable and the covariates of sex, BMI, energy expenditure for recreational sports activities (EErecsport) and leisure-time physical activities (EEltpa) were developed.
Results: Significant decreases in mean heart rate over time appeared for all walking speeds. The covariates of sex and BMI were significantly related to mean heart rate at each walking speed, except for BMI at 7 km/h. No significant relations between EErecsport, EEltpa and mean heart rate occurred, except for EEltpa at 7 km/h. From baseline to T4, decreases in predicted mean heart rate were 5.5, 6.0,
9.0 beats/min at 4-, 5-, 6- and 7 km/h walking speeds; relative decreases ranged from 5.1 to 7.4%.
Conclusions: Significant decreases found in heart rate during submaximal exercise reflected a potential increase in cardiovascular function after 18 months of participation in GALM.
EFFECT OF VIGOROUS PHYSICAL ACTIVITY ON ARTERIAL STIFFNESS IN HIGH SCHOOL BOYSMIURA, H.
LABORATORY FOR APPLIED PHYSIOLOGYIntroduction: Recently, the occurrence of life style-related such as hypertension, atherosclerosis, obesity, and hyperlipemia is increasing in young and old men. One of the reasons for this is lack of physical activity. Physical activity may play a pathophysiological role in the
development of atherosclerosis. Previous research reported that habitual exercise reduced arterial function in middle- to older aged men (Tanaka et al. 2000). However, few attempts have so far been made to identify the role of physical activity in arterial function on younger populations. Therefore, we tried to evaluate the influence of physical activity on arterial stiffness estimated by pulse wave velocity in high school students.
Methods: We studied 183 healthy high school boys aged 15 to 18 years (Height: 169.9±6.3cm; Weight: 63.1±10.2kg; %body fat:
14.6±5.8%). Subjects were divided into two groups: 83 were in the active group who participated in sports or athletic clubs in addition to physical education class and 100 were in the control group who were sedentary. The brachial systolic and diastolic blood pressure (SBP, DBP), and brachial to ankle pulse wave velocity (baPWV) were measured using a volume-plethymographic apparatus while in the supine position. In order to estimate the energy expenditure (EEA) during walking, moderate, and vigorous activities, the International Physical Activity Questionnaire with short format was adopted.
Results: In the active group, EEA during moderate and vigorous activities as well as the baPWV significantly differed from those in the control group (moderate-EEA: 87.3±94.1 vs. 37.5±38.2kcal/day; vigorous-EEA; 753.9±725.4 vs. 33.4±113.7kcal/day; baPWV: 1072.7±133.5 vs. 1150.6±162.7cm/sec, respectively). However, no significant differences of walking-EEA, of SBP, or of DBP were found between the active and control groups (walking-EEA: 5.4±9.5 vs. 8.9±13.9kcal/day; SBP: 124.7±10.2 vs. 124.7±10.1mmHg; DBP: 66.8±7.5 vs.
67.9±7.7mmHg, respectively). No significant correlation was found between all EEA and blood pressures. baPWV was significantly correlated to EEA during vigorous activity (r=-0.27, p0.05).
Discussion: Compared with non-active boys, active high school boys have slower baPWV without any changes in blood pressure. Regular exercise increases the production of nitric oxide more and decreases endotheline-1 less (Maeda et al. 2001). The present results imply that these suggested effects are produced by greater physical activity. The level of physical activity influenced on arterial function in teenagers, which is agreement with previous results in middle- to older aged men (Seals 2003). From these results, spending more time performing vigorous physical activity has a favorable effect on arterial stiffness in teenagers as well as the elderly.
References Maeda S et al. (2001), Life Sci, 69, 1005-1016.
Seals DR. (2003), Exerc Sport Sci Rev, 31, 68-72.
Tanaka H et al. (2000), Circulation, 102, 1270-1275.
VALIDITY OF A WRIST-WORN ACCELEROMETER IN CHILDRENEKBLOM, Ö., NYBERG, G., EKBLOM BAK, E., EKELUND, U., MARCUS, C.
SWEDISH SCHOOL OF SPORT AND HEALTH SCIENCES AND KAROLINSKA INSTITUTETIntroduction: Regular physical activity is a behaviour related to several positive health outcomes in children (Steele, RM, et al). However, the detailed relationships between activity and health outcomes have been hampered due to imprecise methodology, where intensity, type, frequency and duration of physical activity have been difficult to quantify. Furthermore, methodological shortcomings may have contributed to reduced contrast between physically “active” and “inactive” individuals and consequently an underestimation of the risks of physical inactivity. The aim of the present study was to assess the validity of a wrist worn accelerometer (Actiwatch) for estimating energy expenditure during various free-living activities and to determine cut-off values for light, moderate and vigorous intensity.
Methods: Twenty-two normal weight children (mean age [SD] 8.8 [0.9] years) performed eight different activities of different intensities.
Energy expenditure was assessed using indirect caloriometry (Douglas bag technique) during these activities. Additionally, resting metabolic rate was measured at a separate occasion. Actiwatch motion sensors (Cambridge Neurotechnology Ltd Papworth, UK) were worn on the wrist of the non-dominant arm. Epoch length was set to 15 s.