One minute of stair climbing and descending reduces postprandial insulin and glucose with 3-min improving insulin resistance following a mixed meal in young adults: A Randomized Controlled Crossover Trial.

Background: Glycemic markers, including postprandial glucose, insulin, and insulin resistance, are strong predictors of morbidity and mortality in individuals with and without diabetes. Stair-climbing and -descending (SCD) at a comfortable pace for 3 minutes after a sugary beverage (300 kilocalories; 100% carbohydrate) lowers insulin, with insulin sensitivity improving in 10 minutes. If similar benefits are seen following consumption of a mixed meal is unknown. We hypothesize SCD will improve these markers in a dose-response manner following a mixed meal. Methods: In a randomized, controlled, crossover trial, young adults (N = 31) performed SCD for 0 (seated control), 1, 3, and 10 minutes after a mixed meal (650 kilocalories; 53% carbohydrates, 33% fat, and 14% protein). Differences in glucose, insulin, and insulin sensitivity (ISI) from baseline to 30 min were analyzed using a mixed-effects ANOVA. Results: A significant fixed-effect was found for change in glucose [F(2.551,67.17) = 4.724,p = 0.007)], insulin [F(2.692,74.49) = 11.28,p < 0.001)], and ISI [F(2.127,56.00) = 5.848,p = 0.004)]. Compared to the seated control (0 minutes), changes in glucose were lower after 1 minute (-14.0 (-7.2)mg/dL,p < 0.001), 3 minutes (-18.4 (-7.0)mg/dL,p = 0.0007), and 10 minutes (-10.0 (-8.1)mg/dL,p = 0.039); changes in insulin were lower after 1 minute (-1.8 (-0.9)µIU/mL,p = 0.0011), 3 minutes (-2.8 (-0.9)µIU/mL,p < 0.001), and 10 minutes (-1.1 (-0.9)µIU/mL,p = 0.033); and changes in ISI were significantly higher after 3 minutes (2.4 (1.5),p < 0.001) and 10 minutes (1.3 (1.6),p = 0.014) but not 1 minute (1.2 (1.5),p = 0.059). Conclusion: Postprandial glucose and insulin improved with 1 minute, and insulin resistance improved with 3 minutes, of SCD at a self-selected, comfortable pace, after consumption of a mixed meal in apparently healthy young adults. Protocol: Trial registration: ClinicalTrials.gov Identifier: NCT04232475.

Skeletal muscle quality, measured via phase angle, and cardiorespiratory fitness in patients with obesity and heart failure with preserved ejection fraction.

OBJECTIVES: Cardiorespiratory fitness (CRF) is influenced by body composition quantity and quality in heart failure with preserved ejection fraction (HFpEF) and obesity. Bioelectrical impedance analysis (BIA) provides a noninvasive quantitative and qualitative body composition assessment. The aim of this study was to determine the role of phase angle (PhA), a BIA-measure of skeletal muscle quality and body cell mass, on CRF in patients with obesity and HFpEF. METHODS: Fifty-nine consecutive outpatients with HFpEF underwent cardiopulmonary exercise testing to measure CRF. Single-frequency segmental BIA was used to measure PhA and body composition quantity. Resting Doppler echocardiography and biomarkers were measured to assess cardiac function and systemic inflammation. RESULTS: Compared with patients with lower PhA, patients with higher PhA (above mean 5.8°) presented a greater absolute peak oxygen consumption (VO2; 1.83 [1.3-2.1] versus 1.39 [1.1-1.6] L/min, P = 0.003), VO2 peak adjusted for body weight (17.5 [12.3-18.1] versus 13.3 [12.7-15.2] mL/kg/min, P = 0.040), and a lower edema index (48.7 [2.9] versus 51.4% [2.7], P < 0.001) and N-terminal pro-B-type natriuretic peptide (NT-proBNP; 64 [50-121] versus 183 [68-343.5] pg/dL, P < 0.001). In the overall sample, PhA was correlated with absolute VO2 peak (r = 0.468, P < 0.001), VO2 peak adjusted for body weight (r = 0.368, P = 0.004), VO2 peak adjusted for fat-free mass (r = 0.315, P = 0.015), edema index (r = -0.508, P < 0.001), and NT-proBNP (r = -0.579, P < 0.001). PhA remained a significant predictor for CRF even after adjustment for potential confounders and HFpEF severity. CONCLUSION: In patients with obesity and HFpEF, a greater PhA is an independent predictor for favorable CRF.

Systematic Review of the Frequency of Registered Dietitian-Nutritionist Intervention in the Primary Care Setting for Diabetes Self-Management Education for Patients with Type II Diabetes.

PURPOSE: The purpose of this systematic review is to discuss the ideal frequency of Registered Dietitian-Nutritionist (RDN) contact required to improve glycemic control in patients with type 2 diabetes in the primary care setting. METHODS: Researchers completed a literature search between April 1 and June 30, 2020. Researchers identified 184 studies and included seven studies for full-text analysis. Eligible studies were required to occur in a primary care setting, use A1C as an outcome measure, and use some form of education or contact with an RDN. Study quality was assessed using the NIH Study Quality Assessment Tool. RESULTS: Compared to the usual care group of each study, increased contact with an RDN improved A1C lowering regardless of frequency (round-the-clock, monthly, biannually). The largest decreases occurred in the round-the-clockand quarterly touch groups. Studies varied in modality (inperson, telehealth, etc.) and type of intervention. The participants had A1Cs between 8.07% and 10.25% before intervention. With RDN contact of any frequency between provider visits and participants saw A1Cs decreased between 0.66% and 2.2%. CONCLUSION: Greater glycemic control in patients with type 2 diabetes in the primary care environment is linked to more frequent RDN contact than that advised by the American Diabetes Association Standards of Care.

Sex differences in the acute effect of stair-climbing on postprandial blood glucose levels: A randomized controlled trial.

Single, short stair climbing and descending (SCD) bouts of low to moderate intensity effectively lower postprandial blood glucose but previous reports have found conflicting results on interactions by sex during exercise. We hypothesize that SCD at a self-selected intensity will be equally effective at lowering postprandial blood glucose in males and females. Methods and Results: Thirty subjects (age: 23.8 (3.0) years) performed 0, 1, 3, and 10 min of SCD following consumption of a mixed meal. SCD was performed at a self-selected comfortable pace and all bouts ended at minute 28. Postprandial blood glucose was measured every 15 min for 1 h and analyzed as glucose over time, area under the curve (AUC), and incremental AUC (iAUC) using mixed-design ANOVAs with repeated measures. Although there was no interaction between sex and condition or time (p = .129 to .541) for glucose over time, AUC, or iAUC, there was a main effect for sex for glucose over time (p = .004) and AUC (p = .006), but not iAUC (p = .125). Females had higher blood glucose throughout each trial (22% (13 to 31%), p = .004) but both males' and females' postprandial blood glucose was lowered following 10 min of SCD relative to the seated control condition. Conclusions: Males and females benefited equally from single, short SCD bouts of low to moderate intensity despite females having higher blood glucose at all time points. Previous findings of sex differences in the attenuating effect of exercise on postprandial blood glucose are likely due to the use of absolute workloads leading to varying relative intensities.

A single one-minute, comfortable paced, stair-climbing bout reduces postprandial glucose following a mixed meal.

BACKGROUND AND AIMS: Postprandial blood glucose (PBG) is an independent predictor of disease and mortality risk. To date, the shortest, single, moderate-intensity exercise intervention to reduce PBG is a 1 min bout of stair stepping during an oral glucose tolerance test. Whether this effect translates to real meal consumption is unknown. METHODS AND RESULTS: Subjects (N = 30) participated in a randomized controlled crossover trial performing 0 min (seated control), 1 min, 3 min or 10 min of stair climbing and descending bouts (SCD) at a self-selected pace after consumption of a mixed meal on four separate visits. Compared to control, all SCD reduced PBG at least one timepoint: at 30-min the 3 min (-10.8 (-18.7 to -2.8) mg/dL, p = 0.010) and 10 min (-36.3 (-46.4 to -26.3) mg/dL), p < .001), and at 45-min the 1 min (-7.3 (-13.9 to -0.7) mg/dL, p = 0.030, 3 min (-8.7 (-13.9 to -3.6) mg/dL, p = 0.002 and 10 min SCD (-12.2 (-18.2 to -6.1)mg/dL, p < 0.000) reduced PBG. The area under the curve (AUC) for PBG was lower following the 3 min (-4.4% (-7.5 to -1.4%), p = 0.006) and 10 min (-8.9% (-12.4 to -5.3%), p < 0.001), while the incremental AUC (iAUC) was reduced only following the 10 min (-38.0% (-63.7 to -12.3%), p = 0.005) SCD. All SCD were rated by subjects as very light to light intensity. CONCLUSIONS: Single, subjectively "light" intensity stair climbing and descending bouts as short as 1 min in duration attenuate the postprandial glucose response in normal weight individuals following consumption of a mixed meal. More pronounced effects require longer bouts in a dose-dependent manner.

Dissociation from DNA of Type III Restriction-Modification enzymes during helicase-dependent motion and following endonuclease activity.

DNA cleavage by the Type III Restriction-Modification (RM) enzymes requires the binding of a pair of RM enzymes at two distant, inversely orientated recognition sequences followed by helicase-catalysed ATP hydrolysis and long-range communication. Here we addressed the dissociation from DNA of these enzymes at two stages: during long-range communication and following DNA cleavage. First, we demonstrated that a communicating species can be trapped in a DNA domain without a recognition site, with a non-specific DNA association lifetime of ∼ 200 s. If free DNA ends were present the lifetime became too short to measure, confirming that ends accelerate dissociation. Secondly, we observed that Type III RM enzymes can dissociate upon DNA cleavage and go on to cleave further DNA molecules (they can 'turnover', albeit inefficiently). The relationship between the observed cleavage rate and enzyme concentration indicated independent binding of each site and a requirement for simultaneous interaction of at least two enzymes per DNA to achieve cleavage. In light of various mechanisms for helicase-driven motion on DNA, we suggest these results are most consistent with a thermally driven random 1D search model (i.e. 'DNA sliding').