Does Interrupting Prolonged Sitting With 10- or 20-Min Standing Attenuate Postprandial Glycemia and Blood Pressure in Middle-Aged and Older Adults With Type 2 Diabetes?

We carried out three types of 2-hr experimental sessions with middle-aged and older adults with Type 2 diabetes in order to examine the acute effect of interrupting prolonged sitting with varying periods of standing on postprandial glycemia and blood pressure (BP): (a) prolonged sitting after breakfast; (b) standing for 10 min, 30 min after breakfast; and (c) standing for 20 min, 30 min after breakfast. Glucose and BP were assessed before and after breakfast. A generalized linear model revealed no significant differences for the incremental area under the curve of glucose between standing for 10 min, 30 min after breakfast, versus prolonged sitting after breakfast (ß = -4.5 mg/dl/2 hr, 95% CI [-17.3, 8.4]) and standing for 20 min, 30 min after breakfast, versus prolonged sitting after breakfast (ß = 0.9 mg/dl/2 hr, 95% CI [-11.9, 13.7]). There was no difference in area under the curve of systolic and diastolic BP among the sessions. Interrupting prolonged sitting time with 10 or 20 min of standing 30 min after breakfast does not attenuate postprandial glycemia or BP in middle-aged and older adults with Type 2 diabetes.

Physical Activity Counseling for Adults with Hypertension: A Randomized Controlled Pilot Trial.

The effect of physical activity counseling (PAC) in hypertensive adults is unclear. This study investigated the effect of PAC on blood pressure (BP), physical activity level, sitting time, metabolic profile, and body composition in hypertensive adults. Twenty-two hypertensive adults (48.8 ± 7.3 years) participated in this pilot trial. The 12-week PAC was based on the 5 A's model considering the FITT principle (Frequency, Intensity, Time, and Type) of physical activity. The control group received instructions about FITT in one face-to-face meeting at baseline. Pedometer-measured physical activity, sitting time, resting and ambulatory BP, metabolic profile (cholesterol, triglycerides, fasting glucose), and body composition (fat mass, abdominal fat, fat free mass) were assessed. The PAC group showed higher steps per day (5839 ± 992 vs. 5028 ± 902; p = 0.044) and a trend for lower sitting time (5.6 ± 1.3 vs. 8.0 ± 4.0 h/day; p = 0.059) than the control group. No changes were observed in BP, metabolic profile, and body composition (p > 0.05). In conclusion, 12 weeks of a PAC program based on the 5 A's model resulted in a modest increase of ~800 steps per day and a trend to decrease ~2 h/day in sitting time, but there were no associated reduction in BP and improvements in metabolic and body composition.

Physical activity level and perceived exertion predict in-task affective valence to low-volume high-intensity interval exercise in adult males.

Previous results reveal a decline in affective valence in response to progressive exercise in adults. However, this similar decline is not universally observed in response to high intensity interval exercise (HIIE), which may be due to its intermittent nature. The aim of the current study was to examine potential predictors of the in-task affective valence to low-volume HIIE (LV-HIIE; 10 × 60 s high-intensity intervals at 90% of maximal treadmill velocity interspersed by 60 s at 30% of maximal treadmill velocity). We analyzed data from 76 males (age and body mass index = 26.5 ±â€¯4.4 yr and 27.3 ±â€¯5.4 kg/m2) who had participated in previous investigations in our lab. Throughout each session, affective valence (Feeling Scale; + 5 to -5), rating of perceived exertion (RPE; Borg scale 6 to 20), and heart rate (HR) were measured. The predictors of in-task affective valence were analyzed during different phases of the LV-HIIE session (i.e. beginning, average of high-intensity intervals 1-3; middle, average of high-intensity intervals 4-7; and end, average of high-intensity intervals 8-10). Results showed a significant decline in affective valence (p < 0.001), increase in RPE (p < 0.001) and HR (p < 0.001) in response to LV-HIIE. Primary predictors of in-task affective valence to LV-HIIE were physical activity level and RPE (beginning, R2 = 0.511, p < 0.001; middle, R2 = 0.681, p < 0.001; end, R2 = 0.742, p = 0.008). In conclusion, physical activity level and perceived exertion significantly predict the in-task affective valence to LV-HIIE in adult males.

Short-Term Resistance Training Improves Cardiac Autonomic Modulation and Blood Pressure in Hypertensive Older Women: A Randomized Controlled Trial.

Oliveira-Dantas, FF, Brasileiro-Santos, MdS, Thomas, SG, Silva, AS, Silva, DC, Browne, RAV, Farias-Junior, LF, Costa, EC, and Santos, AdC. Short-term resistance training improves cardiac autonomic modulation and blood pressure in hypertensive older women: a randomized controlled trial. J Strength Cond Res 34(1): 37-45, 2020-This randomized controlled trial investigated the efficacy of short-term resistance training (RT) on cardiac autonomic modulation and peripheral hemodynamic parameters in hypertensive older women. Twenty-five hypertensive older women who were insufficiently active (64.7 ± 4.7 years) participated in this study. Subjects were randomly allocated to a 10-week RT program (2 d·wk in the first 5 weeks; 3 d·wk in the last 5 weeks) or a nonexercise control group. Linear reverse periodization was used for the RT program. Cardiac autonomic modulation, mean blood pressure (MBP), peripheral vascular resistance (PVR), and resting heart rate (RHR) were measured before and after 10 weeks. The RT group reduced cardiac sympathetic modulation (0V%; B = -6.6; 95% confidence interval [CI]: -12.9 to -0.2; p = 0.045; Cohen's d = 0.88) and showed a trend for increased parasympathetic modulation (2V%; B = 12.5; 95% CI: 0-25; p = 0.050; Cohen's d = 0.87) compared with the control group. The RT group reduced MBP (B = -8.5 mm Hg; 95% CI: -13.6 to -3.4; p = 0.001; Cohen's d = 1.27), PVR (B = -14.1 units; 95% CI: -19.9 to -8.4; p < 0.001; Cohen's d = 1.86), and RHR (B = -8.8 b·min; 95% CI: -14.3 to -3.3; p = 0.002; Cohen's d = 1.20) compared with the control group. In the RT group, the changes in 2V% patterns and low-frequency components showed a correlation with changes in MBP (r = -0.60; p = 0.032) and RHR (r = 0.75; p = 0.0003). In conclusion, 10 weeks of RT improved cardiac autonomic modulation and reduced MBP and PVR in hypertensive older women. These results reinforce the importance of RT for this population.

Effects of High-Intensity Interval and Moderate-Intensity Continuous Exercise on Physical Activity and Sedentary Behavior Levels in Inactive Obese Males: A Crossover Trial.

A total of 17 participants (30.2 ± 4.8 years; 35.4 ± 4 kg/m2; 38.2 ± 3.6 % body fat) were enrolled in this randomized crossover trial to analyze the effects of a single session of high-intensity interval (HIIE) and moderate-intensity continuous exercise (MICE) on the physical activity and sedentary behavior levels in inactive obese males. The participants performed two exercise sessions and one control session (no exercise): i) low-volume HIIE (10 x 60 s at 90% of maximal aerobic velocity [MAV] interspaced by 60 s at 30% of MAV); ii) MICE (20 min at 70% of maximum heart rate); and iii) control (25 min in a seated position). After all sessions, the physical activity and sedentary behavior levels were monitored by accelerometer over seven consecutive days. No differences in the physical activity (activity counts, and time spent at light, moderate, and vigorous intensities) and sedentary behavior (time spent at sedentary behavior, breaks, and bouts) levels were found among the sessions (HIIE, MICE and control) (p > 0.05). In summary, a single session of HIIE and MICE does not change the physical activity and sedentary behavior levels in inactive obese males. Therefore, low-volume of both high- and moderate-intensity exercise should be considered for inactive obese males given that it does not reduce the physical activity level or increase the time spent at sedentary behavior.

Effect of Acute Dietary Nitrate Supplementation on the Post-Exercise Ambulatory Blood Pressure in Obese Males: A Randomized, Controlled, Crossover Trial.

This study aimed to verify the effect of beetroot juice on post-exercise ambulatory blood pressure (BP) in obese individuals. Fourteen non-hypertensive obese males were randomly assigned to three experimental sessions: 1) Beetroot juice with exercise (BJE, 200ml with ≈ 800mg nitrate and 40 minutes of moderate-intensity aerobic exercise at an intensity of 50% of the heart rate reserve), 2) fruit soda with exercise (FSE, 200ml of a low-nitrate drink and the same exercise session) and 3) control (CON, 200ml of water, an insignificant nitrate drink without exercise). The concentration of total nitrites and nitrates in plasma (NOx) after the drinks and the 24-hour ambulatory BP were evaluated. A two-way (condition vs. time) ANOVA for repeated measures, with a Bonferroni post hoc was used to analyze variables. The plasma NOx concentration increased significantly after ingestion of beetroot juice (from 9.9 ± 8.4 µM to 47.0 ± 16.9 µM, p < 0.001) and remained elevated until 1 hour post-intervention (54.7 ± 10.1 µM, p < 0.001), while it did not change in FSE and CON groups. The BJE session decreased ambulatory systolic BP in 5.3 mmHg (IC95%, -10.1 to -0.6, p = 0.025) in the period of 1-6 h after the BJE session compared to the CON session and reduction of 3.8 mmHg (IC95%, -7.5 to -0.007, p = 0.05) compared to the FSE session. No significant changes were observed for ambulatory diastolic BP (p > 0.05). BJE enhanced the reduction of systolic ambulatory BP up to 6 hours following a moderate-intensity aerobic exercise in obese individuals with an elevated cardiovascular risk profile.

Effect of Low-Volume High-Intensity Interval Exercise and Continuous Exercise on Delayed-Onset Muscle Soreness in Untrained Healthy Males.

Farias Junior, LF, Browne, RAV, Frazão, DT, Dantas, TCB, Silva, PHM, Freitas, RPA, Aoki, MS, and Costa, EC. Effect of low-volume high-intensity interval exercise and continuous exercise on delayed-onset muscle soreness in untrained healthy males. J Strength Cond Res 33(3): 774-782, 2019-The aim of this study was to compare the effect of a single session of a low-volume high-intensity interval exercise (HIIE) and a continuous exercise (CE) on the magnitude of delayed-onset muscle soreness (DOMS) in untrained healthy males. Fifteen participants (25.1 ± 4.4 years) completed 2 experimental sessions in a randomized order: (a) low-volume HIIE: 10 × 60 seconds at 90% of maximal velocity (MV) interspersed with 60 seconds of active recovery at 30% of MV and (b) CE: 20 minutes at 60% of MV. Pressure-pain threshold (PPT), pressure-pain tolerance (PPTol), and perceived pain intensity (PPI) were assessed in the rectus femoris, biceps femoris, and gastrocnemius before and 24 hours after exercise. There was a decrease of PPT in the rectus femoris (-0.5 kg·cm) and PPTol in the gastrocnemius (-1.4 kg·cm) and an increase of PPI in the rectus femoris (14.4 mm) and in the biceps femoris (11.7 mm) 24 hours after the low-volume HIIE session (p ≤ 0.05). There was a decrease of PPT (rectus femoris: -0.8 kg·cm; biceps femoris: -0.5 kg·cm; gastrocnemius: -0.9 kg·cm) and PPTol (rectus femoris: -1.9 kg·cm; biceps femoris: -2.7 kg·cm; gastrocnemius: -1.6 kg·cm) and an increase of PPI (rectus femoris: 8.1 mm; biceps femoris: 10.3 mm; gastrocnemius: 17.5 mm) in all muscles 24 hours after the CE session (p ≤ 0.05). No difference was observed between HIIE and CE sessions in any DOMS-related parameter (p > 0.05). In conclusion, a single session of low-volume HIIE and CE elicited a similar mild DOMS 24 hours after exercise in untrained healthy males.

Short-Term Psychological and Physiological Effects of Varying the Volume of High-Intensity Interval Training in Healthy Men.

We assessed the short-term effects of varying the volume of high-intensity interval training (HIIT) on psychological and physiological responses of 23 healthy adult males ( M = 21 years; M peak oxygen uptake [VO2peak] = 47.2 ml·kg-1·min-1). Participants were randomly assigned to low- and very-low-volume HIIT groups and engaged in nine supervised exercise sessions over three weeks. The low-volume HIIT group performed 8-12 60-second work bouts on a cycle ergometer at the peak power output achieved during the incremental test, interspersed by 75 seconds of low-intensity active recovery. The very-low-volume HIIT performed 4-6 work bouts with the same intensity, duration, and rest intervals. During training, participants' ratings of perceived exertion (Borg Category Ratio-10 scale) and their affective responses (Feeling Scale -5/+5) during the last 15 seconds of each work bout were recorded. Physiological data were VO2peak, endurance, and anaerobic performance before and after the intervention. Throughout training, participants in the very-low-volume group (relative to the low-volume group) reported lower ratings of perceived exertion in Week 1 ( M = 4.1 vs. M = 6.3; p < .01) and Week 3 ( M = 4.0 vs. M = 6.2; p < .01), and higher affective response in these same two weeks (Week 1: M = 1.9 vs. M = 0.3; p = .04; Week 3: M = 2.1 vs. M = 0.9; p = .06). Regarding physical fitness, Wingate peak power increased significantly after training in the very-low-volume HIIT group ( M = 1,049 W vs. M = 1,222 W; p < .05), but not in the low-volume HIIT group ( M = 1,050 W vs. M = 1,076 W). No significant change was found after training in physiological variables of peak power output, VO2peak, and endurance performance. In summary, in this short-term training period, the very-low-volume HIIT enhanced anaerobic capacity and was perceived as less strenuous and more pleasurable than low-volume HIIT.

Reproducibility of ambulatory blood pressure after high-intensity interval training sessions in healthy individuals.

This study analyzed the reproducibility of ambulatory blood pressure (BP) after high-intensity interval training (HIIT) sessions. Seventeen normotensive men (23.5±2.4 years) underwent two HIIT and two control sessions separated by 7-10 days. Ambulatory BP monitoring devices were used for 20 h. The intraclass correlation coefficient of BP in the awake and asleep periods ranged from 0.836 to 0.942 in the HIIT (P<0.05) and from 0.777 to 0.974 in the control sessions (P<0.05). The bias, limits of agreement, and pattern of distribution of awake BP were similar between HIIT and control sessions. However, for asleep BP, the bias and limits of agreement were not similar between HIIT and control sessions. In conclusion, in physically active adults, ambulatory BP after HIIT sessions presented good reproducibility only in the awake period.

Carbohydrate Mouth Rinse and Hydration Strategies on Cycling Performance in 30 Km Time Trial: A Randomized, Crossover, Controlled Trial.

The aim of this study was to investigate whether carbohydrate mouth rinse (CMR) improves physical performance of cyclists during a 30-km time trial test and its influence on water balance compared to other strategies of fluid intake. Eleven recreationally trained male cyclists completed a 30 km time trial cycle ergometer under three experimental interventions: (a) CMR, (b) drinking to replace all weight loss (DWL), and (c) drinking "ad libitum" (DAL). Time to complete the 30 km time trial, heart rate, average power, velocity, weight loss, urine color, urine density and pH were evaluated. Statistical analysis was performed using repeated measures analysis of variance (RM-ANOVA) and generalized estimating equations (GEE) with Bonferroni adjustment (p < 0.05). Time to complete the 30 km time trial was similar among CMR 54.5 ± 2.9 min, DWL 53.6 ± 3.9 min and DAL 54.5 ± 2.5 min (p = 0.13). CMR (1.7 ± 0.4%) elicited similar water loss compared to the DAL (1.4 ± 0.6%) intervention, but it was higher than the DWL intervention (0.6 ± 0.6%) (p < 0.01). CMR did not improve the performance of recreationally trained cyclists in a 30 km time trial test compared to other fluid intake strategies. Furthermore, CMR causes higher water loss compared to DWL intervention.

The effect of carbohydrate mouth rinse on performance, biochemical and psychophysiological variables during a cycling time trial: a crossover randomized trial.

BACKGROUND: The hypothesis of the central effect of carbohydrate mouth rinse (CMR) on performance improvement in a fed state has not been established, and its psychophysiological responses have not yet been described. The aim of this study was to evaluate the effect of CMR in athletes fed state on performance, biochemical and psychophysiological responses compared to ad libitum water intake. METHODS: Eleven trained male cyclists completed a randomized, crossover trial, which consisted of a 30 km cycle ergometer at self-selected intensity and in a fed state. Subjects were under random influence of the following interventions: CMR with a 6% unflavored maltodextrin solution; mouth rinsing with a placebo solution (PMR); drinking "ad libitum" (DAL). The time for completion of the test (min), heart rate (bpm) and power (watts), rating of perceived exertion (RPE), affective response, blood glucose (mg/dL) and lactate (mmol/DL), were evaluated before, during and immediately after the test, while insulin (uIL/mL), cortisol (µg/dL) and creatine kinase (U/L) levels were measured before, immediately after the test and 30 min after the test. RESULTS: Time for completion of the 30 km trial did not differ significantly among CMR, PMR and DAL interventions (means = 54.5 ± 2.9, 54.7 ± 2.9 and 54.5 ± 2.5 min, respectively; p = 0.82). RPE and affective response were higher in DAL intervention (p < 0.01). Glucose, insulin, cortisol and creatine kinase responses showed no significant difference among interventions. CONCLUSIONS: In a fed state, CMR has not caused metabolic changes, and it has not improved physical performance compared to ad libitum water intake, but demonstrated a possible central effect. ReBec registration number: RBR-4vpwkg. Available in http://www.ensaiosclinicos.gov.br/rg/?q=RBR-4vpwkg.

A Single Session of Low-Volume High-Intensity Interval Exercise Reduces Ambulatory Blood Pressure in Normotensive Men.

Dantas, TCB, Farias Junior, LF, Frazão, DT, Silva, PHM, Sousa Junior, AE, Costa, IBB, Ritti-Dias, RM, Forjaz, CLM, Duhamel, TA, and Costa, EC. A single session of low-volume high-intensity interval exercise reduces ambulatory blood pressure in normotensive men. J Strength Cond Res 31(8): 2263-2269, 2017-The magnitude and duration of postexercise hypotension (PEH) may provide valuable information on the efficacy of an exercise approach to blood pressure (BP) control. We investigated the acute effect of a time-efficient high-intensity interval exercise (HIIE) on ambulatory BP. Twenty-one normotensive men (23.6 ± 3.6 years) completed 2 experimental sessions in a randomized order: (a) control (no exercise) and (b) low-volume HIIE: 10 × 1 minute at 100% of maximal treadmill velocity interspersed with 1 minute of recovery. After each experimental session, an ambulatory BP monitoring was initiated. Paired sample t-test was used to compare BP averages for awake, asleep, and 20-hour periods between the control and the low-volume HIIE sessions. A 2-way repeated measures analysis of variance was used to analyze hourly BP after both experimental sessions. Blood pressure averages during the awake (systolic: 118 ± 6 vs. 122 ± 6 mm Hg; diastolic: 65 ± 7 vs. 67 ± 7 mm Hg) and 20-hour (systolic: 115 ± 7 vs. 118 ± 6 mm Hg; diastolic: 62 ± 7 vs. 64 ± 7 mm Hg) periods were lower after the low-volume HIIE compared with the control (p ≤ 0.05). Systolic and diastolic PEH presented medium (Cohen's d = 0.50-0.67) and small (Cohen's d = 0.29) effect sizes, respectively. Systolic PEH occurred in a greater magnitude during the first 5 hours (3-5 mm Hg). No changes were found in asleep BP (p > 0.05). In conclusion, a single session of low-volume HIIE reduced ambulatory BP in normotensive men. The PEH occurred mainly in systolic BP during the first 5 hours postexercise.

Slow Down and Enjoy: The Effects of Cycling Cadence on Pleasure.

Pleasure plays a key role in exercise behavior. However, the influence of cycling cadence needs to be elucidated. Here, we verified the effects of cycling cadence on affect, perceived exertion (ratings of perceived exertion), and physiological responses. In three sessions, 15 men performed a maximal cycling incremental test followed by two 30-min constant workload (50% of peak power) bouts at 60 and 100 r/min. The pleasure was higher when participants cycled at 60 r/min, whereas ratings of perceived exertion, heart rate, and oxygen uptake were lower ( p < .05). Additionally, the rate of decrease in pleasure and increase in ratings of perceived exertion was less steep at 60 r/min ( p < .01). Cycling at 60 r/min is more pleasant, and the perceived effort and physiological demand are lower than at 100 r/min.