Percent Change In Time Research Articles

Effects of exercise anticipation on cardiorespiratory responses before and after start of dynamic exercise at various intensities

The purpose of this study was to examine the effects of exercise anticipation on time-dependent cardiorespiratory response preceding and after onset of dynamic exercise at various intensities. Experiments were conducted by two different groups of subjects; one group (N=11) for the experiment to test preparatory cardiorespiratory responses to exercise intensity (Exp.1), and the other group (N=15) for the experiment to test the effect of unexpected timing of high intensity exercise on the cardiorespiratory function (Exp.2). In Exp.1, the quantitative and temporal changes in cardiorespiratory and metabolic responses during pre-exercise resting periods changed over time, depending on the subsequent exercise intensity. In Exp.2, The initial increases in cardiorespiratory and metabolic responses after the onset of exercise under anticipation condition were significantly different from those under non-anticipation condition, and the difference in heart rate (HR) responses between the 2 conditions varied in a time-dependent manner. The time to exhaustion and initial HR increase after the start of high-intensity exercise under anticipation condition were higher than those under non-anticipation condition. A significant correlation was observed between percent change in time to exhaustion and percent change in HR in the anticipation condition versus the non-anticipation condition in each time before and after the start of exercise. Anticipatory control mechanisms of the cardiorespiratory system via the higher brain preceding exercise initiation may plays an important role in minimizing the time delay of circulatory response and metabolic cost after the onset of dynamic exercise, thereby enhancing physiological efficiency and maximal exercise performance during high-intensity exercise.

Real-World Efficacy of the Hybrid Closed-Loop System.

Hybrid closed-loop (HCL) insulin pump therapy (Medtronic 670G) is an emerging technology that is growing in use worldwide. Initial clinical trials demonstrated the effectiveness of HCL in reducing hypoglycemia and improving glucose control; however, these subjects were intensely monitored and supervised. There has been concern regarding the ability of patients to remain in auto mode. We aimed to assess HCL when used in a typical outpatient endocrine clinic. We initially analyzed data from 80 individuals with type 1 diabetes managed in an endocrine clinic by a single certified diabetes educator (CDE). We then included our other providers and had 230 subjects by the end of the study. Patients were either transitioned from traditional insulin pump or multiple daily insulin injection therapy (MDI) to HCL. Patients initiated to HCL pump therapy from July 2017 through February 2020 were studied. Endpoints of change in time in hypoglycemic/hyperglycemic range and time in target range were analyzed. The primary outcome was a change in percent time in the target range during manual mode compared with auto mode. There was an 18.2% increase in average time in target range when comparing manual mode to auto mode (59.3% vs 70.1%, P < .0001). Average time in hyperglycemic range was significantly reduced by 26.7% (39.0% vs 28.6%, P < .0001) but without increasing average time in hypoglycemic range (1.7% vs 1.3%, P = 0.95). HCL was effective in reducing hyperglycemia and increasing time in the target range but did not increase hypoglycemia. These data suggest HCL will improve the metrics of glucose control.

Glycemic Outcomes in Adults With Type 2 Diabetes Participating in a Continuous Glucose Monitor-Driven Virtual Diabetes Clinic: Prospective Trial.

BackgroundThe Onduo virtual diabetes clinic (VDC) for people with type 2 diabetes (T2D) combines a mobile app, remote personalized lifestyle coaching, connected devices, and live video consultations with board-certified endocrinologists for medication management and prescription of real-time continuous glucose monitoring (RT-CGM) devices for intermittent use.ObjectiveThis prospective single-arm study evaluated glycemic outcomes associated with participation in the Onduo VDC for 4 months.MethodsAdults aged ≥18 years with T2D and a baseline glycated hemoglobin (HbA1c) of ≥8% to ≤12% were enrolled from 2 primary care centers from February 2019 to October 2019. Participants were asked to engage at ≥1 time per week with their care team and to participate in a telemedicine consultation with a clinic endocrinologist for diabetes medication review. Participants were asked to use a RT-CGM device and wear six 10-day sensors (total 60 days of sensor wear) intermittently over the course of 4 months. The primary outcome was change in HbA1c at 4 months from baseline. Other endpoints included change in weight and in RT-CGM glycemic metrics, including percent time <70, 70-180, 181-250, and >250 mg/dL. Changes in blood pressure and serum lipids at 4 months were also evaluated.ResultsParticipants (n=55) were 57.3 (SD 11.6) years of age, body mass index 33.7 (SD 7.2), and 40% (22/55) female. HbA1c decreased significantly by 1.6% (SD 1%; P<.001). When stratified by baseline HbA1c of 8.0% to 9.0% (n=36) and >9.0% (n=19), HbA1c decreased by 1.2% (SD 0.6%; P<.001) and 2.4% (SD 1.3%; P<.001), respectively. Continuous glucose monitoring–measured (n=43) percent time in range (TIR) 70-180 mg/dL increased by 10.2% (SD 20.5%; P=.002), from 65.4% (SD 23.2%) to 75.5% (SD 22.7%), which was equivalent to a mean increase of 2.4 hours TIR per day. Percent time 181-250 mg/dL and >250 mg/dL decreased by 7.2% (SD 15.4; P=.005) and 3.0% (SD 9.4; P=.01), respectively. There was no change in percent time <70 mg/dL. Mean weight decreased by 9.0 lb (SD 10.4; P<.001). Significant improvements were also observed in systolic blood pressure, total cholesterol, low-density lipoprotein cholesterol, and triglycerides (P=.04 to P=<.001).ConclusionsParticipants in the Onduo VDC experienced significant improvement in HbA1c, increased TIR, decreased time in hyperglycemia, and no increase in hypoglycemia at 4 months. Improvements in other metabolic health parameters including weight and blood pressure were also observed. In conclusion, the Onduo VDC has potential to support people with T2D and their clinicians between office visits by increasing access to specialty care and advanced diabetes technology including RT-CGM.Trial RegistrationClinicalTrials.gov NCT03865381; https://clinicaltrials.gov/ct2/show/NCT03865381

Repeated-Sprint Ability in Division I Collegiate Male Soccer Players: Positional Differences and Relationships With Performance Tests

Lockie, RG, Moreno, MR, Orjalo, AJ, Stage, AA, Liu, TM, Birmingham-Babauta, SA, Hurley, JM, Torne, IA, Beiley, MD, Risso, FG, Davis, DL, Lazar, A, Stokes, JJ, and Giuliano, DV. Repeated-sprint ability in Division I collegiate male soccer players: positional differences and relationships with performance tests. J Strength Cond Res 33(5): 1362-1370, 2019-Repeated-sprint ability (RSA) in essential for soccer. Important considerations when assessing RSA is whether there are differences between positions (defenders, midfielders, and forwards), and what physiological characteristics may contribute to RSA. This has not been assessed in collegiate male players. Eighteen Division I male field players from one school performed several performance tests. The RSA test involved 7 × 30-m sprints completed on 20-second cycles. Measurements included total time (TT), and performance decrement (percent change in time from the first to last sprint; PD). Subjects also completed tests of lower-body power (vertical [VJ] and standing broad jump [SBJ]); linear (30-m sprint; 0-5 m, 0-10 m, 0-30 m intervals) and change-of-direction (505) speed; and soccer-specific endurance (Yo-Yo Intermittent Recovery Test Level 2; YYIRT2). A one-way analysis of variance (p < 0.05) determined between-position differences, and effect sizes were calculated. Pearson's correlations (p < 0.05) calculated relationships between RSA TT and PD with the other tests. There were no significant between-position differences for any test. There were large effects for the faster right-leg 505 and greater YYIRT2 distance for midfielders compared with defenders and forwards. Nonetheless, no between-position differences in RSA TT and PD were documented. There were relationships between RSA TT and the VJ (r = -0.59), SBJ (r = -0.61), 0-10 m (r = 0.64) and 0-30-m (r = 0.83) sprint intervals. There were no significant correlations for RSA PD. Male field players from one collegiate soccer team can demonstrate similar RSA across different positions. Greater lower-body power and sprinting speed could augment RSA.

OR14-2 Liraglutide Treatment in Overweight and Obese Patients with Type 1 Diabetes: A 26 weeks Randomized Controlled Trial

We have previously demonstrated that a 12-week addition of liraglutide to insulin therapy in patients with type 1 diabetes (T1D) results in an improvement in glycemic control, weight loss and a reduction in systolic blood pressure (SBP). We have now conducted a 6 month randomized study investigating effects of liraglutide in overweight and obese patients with T1DM. All patients had T1D for at least one year, were on insulin therapy and had no detectable c-peptide in plasma (mean BMI: 31.2±1.1kg/m2, mean HbA1c: 7.85±0.19%, mean age: 46.1±1.7 years, mean age of T1D diagnosis: 18.5±2.2 years). Twenty seven and 37 patients (out of total of 85 randomized patients) who received placebo or 1.8mg Liraglutide, respectively, for 26 weeks completed the study. Continuous glucose monitoring (CGM) was performed for 2 weeks before and at end of treatment. At the end of 26 weeks treatment with liraglutide, HbA1c fell significantly by 0.41±0.18% (p=0.001 vs baseline) from 7.96±0.19 to 7.55±0.18%. Placebo adjusted fall in HbA1c was 0.34±0.14 (p= 0.037) at 12 weeks and 0.29±0.19% (p=0.1) at 26 weeks. Placebo adjusted weekly average blood glucose fell by 14±5mg/dl (p=0.069 vs placebo) from 182±7 to 166±6mg/dl (p=0.021 vs baseline) and fasting weekly glucose fell by 11±9mg/dl (p=0.086 vs placebo) from 175±8 to 159±11mg/dl (p=0.032 vs baseline). There was no significant change in percent time spent in hypoglycemic range while the percent time spent in normal range (70-160mg/dl) increased significantly by 7±2% (from 44±3% to 51±2%, p=0.015) and time spent in hyperglycemic range (>160mg/dl) decreased by 8±3% (from 52±4 to 44±4%, p=0.019). There was also a concurrent fall in total and bolus insulin doses. Weight fell by 4.6±0.8kg (placebo adjusted, p=0.001) in the liraglutide group mostly in the form of fat mass loss (3.2±0.6kg, p=0.01 vs placebo) with no change in lean mass as measured by DEXA. Placebo corrected SBP also fell following liraglutide treatment by 5±3mmHg (p=0.076) from 125±3 to 120±3mmHg (p=0.023 vs baseline) with no change in diastolic BP. We conclude that the addition of liraglutide to insulin treatment in obese and overweight patients with type 1 diabetes improves indices of glycemia, body weight and blood pressure without additional risk of hypoglycemia.

Liraglutide as an Additional Treatment to Insulin in Patients with Type 1 Diabetes Mellitus—A 52-Week Randomized Double-Blinded Placebo-Controlled Clinical Trial

We have previously demonstrated that a 12-week addition of liraglutide to insulin therapy in patients with type 1 diabetes (T1D) results in an improvement in glycemic control, weight loss and a reduction in systolic blood pressure (SBP). We have now conducted a 1 year randomized study investigating effects of liraglutide in patients with T1DM. All patients had T1D for at least one year, were on insulin therapy and had no detectable c-peptide in plasma (mean BMI: 28.9±1.4kg/m2, mean HbA1c: 7.82±0.16%, mean age: 46.7±1.9 years, mean age of T1D diagnosis: 22.3±1.7 years). They were randomized to receive placebo, (n=20) or 1.8mg Liraglutide (n= 26) daily for 52 weeks. Continues glucose monitoring (CGM) was performed for 4 weeks before and at end of treatment. At the end of 52 weeks treatment with liraglutide, placebo adjusted HbA1c fell significantly by 0.57±0.17% (p=0.006 vs. placebo) from 7.920.15± to 7.45±0.12% (p=0.009). Weekly placebo adjusted average blood glucose fell by 15±4mg/dl (p=0.014 vs. placebo) from 174±5 to 156±6mg/dl (p=0.021) and fasting weekly glucose fell by 8±7mg/dl (p=0.075 vs. placebo) from 165±7 to 153±9mg/dl (p=0.032). There was no change in reported incidences of hypoglycemia and no change in percent time spent below 70mg/dl based on CGM. Total insulin dose did not alter. There was a significant weight loss by 2.5±0.9kg (placebo adjusted, p=0.041 vs. placebo) from 83.6±4.1 to 80.5±4.0kg (p=0.01) in the liraglutide group. Placebo corrected SBP also fell following liraglutide treatment by 9±3mmHg (p=0.031) from 128±3 to 122±3 mmHg while placebo adjusted diastolic BP fell by 5±1mmHg from (79±2 to 75±2mmHg). We conclude that the addition of liraglutide to insulin treatment in type 1 diabetes significantly reduced HbA1c, mean and fasting blood glucose, blood pressure and body weight without significant increase in hypoglycemia. Disclosure P. Dandona: Advisory Panel; Self; AstraZeneca. Consultant; Self; AstraZeneca. Research Support; Self; AstraZeneca. H. Ghanim: None. N.D. Kuhadiya: Speaker's Bureau; Self; AstraZeneca, Novo Nordisk A/S, Janssen Scientific Affairs, LLC.. Advisory Panel; Self; AstraZeneca. Consultant; Self; Dexcom, Inc.. T. Shah: None. J.M. Hejna: None. A. Makdissi: Speaker's Bureau; Self; Eli Lilly and Company. M. Batra: Speaker's Bureau; Self; Eli Lilly and Company. A. Chaudhuri: Speaker's Bureau; Self; AstraZeneca, Eli Lilly and Company, Boehringer Ingelheim Pharmaceuticals, Inc., Merck &amp; Co., Inc., Novo Nordisk Inc..

RESPONSE

Dear Editor-in-Chief: “Constants that vary” (1) elegantly summarizes the fact that parameters in any fixed-effects model are constants only in the sense of representing values of population means, because values of the parameters for individuals always vary from the mean. We ourselves pointed out how the mean value for a factor converting changes in time to exhaustion into changes in time-trial time provides only an approximation for individuals, and we explained how to use several times to exhaustion for more precise conversion (2). The approximation is not as bad as Atkinson and Nevill think. Consider a study in which a single time to exhaustion is used pre and post a treatment, and assume that the underlying mean change in power output is typical for interventions aimed at athletic performance, say 2.0%. The apparently large between-subject variation of 28% in the conversion factor produces an error of typically only 0.5% in an individual's 2.0% change. This error is small compared with the standard error of measurement of power output in time trials, which is approximately 2–3% (4); it may also be negligible compared with the variation arising from individual responses to the treatment. This insight helps explain why interventions producing small changes in power output have been studied successfully with times to exhaustion. Atkinson and Nevill requested analysis of reliability of time-trial times predicted from times to exhaustion “using estimates of model parameters specific to a particular subject at a specific time.” We reported such predictions and analyses in Figure 1 and Table 3 of our paper. The outcome—low within-runner variability—was our empirical evidence that times to exhaustion are inherently reliable. Atkinson and Nevill's concerns about pacing are addressed partly in our reply (3) to Jeukendrup and Currell (5). Their suggestion that boredom contributes to the large within-subject variability in time to exhaustion echoes that in a paper coauthored by one of us in 1998 (6). We now know that the variability is due mainly to the shape of the power–duration curve, but the extent to which boredom contributes for anyone making near-maximal effort in any kind of long endurance test is unclear. For this and other reasons, the best endurance test for elite athletes is still not known. Atkinson and Nevill's suggestion that measurement of physiological variables at set times could give clues to subjects about elapsed time in time-to-exhaustion tests is insightful, and measurement protocols need to be devised to avoid this potential problem. As with Jeukendrup and Currell, we are disappointed with Atkinson and Nevill's failure to recognize our achievements. The casual reader of these two letters and of our paper—like the authors of the letters themselves—may not appreciate that, among much else, we have derived factors that allow a quick and reasonably accurate conversion of a percent change in a time to exhaustion into a practical percent change in time-trial time. These factors, and those for longer tests (4), are particularly useful for interpreting outcomes in published studies where time to exhaustion is the outcome measure. Will G. Hopkins, Ph.D. Erica A. Hinckson, Ph.D. Division of Sport and Recreation Auckland University of Technology Auckland, New Zealand

Hypercapnia alters sleep state pattern.

Mild hypercapnia in the adult animal does not affect sleep pattern but more severe hypercapnia in the fetus increases the duration of REM sleep. Adult male rats were exposed daily for 2-3 h sessions at random to 6, 7, and 8% CO2 or room air. Breathing CO2 caused a 60% increase in sleep onset latency, a 28% decrease in sleep duration, but no change in percent time spent in REM. However, the duration of REM sleep episodes increased by 30%. Thus, in both fetal and adult animals severe hypercapnia appears to have a similar effect on sleep pattern.