Maximal Heart Rate Reserve Research Articles

Age-predicted maximal heart rate reserve as an alternative prognostic parameter in patients with heart failure with preserved ejection fraction -insights from PURSUIT-HFpEF registry-

Abstract Background Heart rate reserve (HRR), a measure of chronotropic response, is a prognostic parameter in patients with heart failure with preserved ejection fraction (HFpEF). However, exercise testing and measuring maximum heart rate (HR) are sometimes difficult in patients with heart failure with preserved ejection fraction (HFpEF). Assessing age-predicted maximal HRR (APHRR), defined as the difference between the resting HR and the age-predicted maximum HR (220 - age), would be a simple alternative to HRR. Purpose To assess the impact of APHRR at discharge on prognosis in patients with HFpEF. Methods An analysis was performed from a prospective multicenter observational registry for HFpEF (PURSUIT-HFpEF Registry) conducted in the Osaka region of Japan. A total of 1231 patients hospitalized for acute heart failure (diagnosed by using Framingham criteria) met the inclusion criteria: a left ventricular ejection fraction ≥50% and brain natriuretic peptide level ≥100 pg/ml. Excluding patients with permanent pacemakers, we enrolled 918 patients (age, 81 ± 9 years; men, 45%; atrial fibrillation, 38%) whose follow-up data after survival discharge were available. Results There was a moderate correlation between HR (median 69, interquartile range [IQR] 61-79 beats per minute [bpm]) and APHRR at discharge (71, 59-81 bpm) (r² = 0.68, p <0.001). During the median follow-up period of 23.8 months [IQR, 12.5-36.3] after discharge, 267 patients (15.4%) died, and the mortality rates incrementally decreased according to the APHRR quartiles (Q1, 44.6%; Q2, 26.6%; Q3, 26.2%; Q4, 18.4%; p <0.001). Cox regression analysis revealed that both the resting HR (hazard ratio per quartile increase, 1.16; 95% confidence interval, 1.04-1.30, p = 0.008) and APHRR (0.67; 0.60-0.75, p <0.001) were associated with mortality. However, the diagnostic accuracy was significantly superior in the APHRR than in resting HR (area under the curve; 0.628 vs. 0.552, p <0.001). Conclusions Assessment of the APHRR at discharge was a simple and useful method for risk stratification of patients with HFpEF. An incremental favorable prognosis indicated the prognostic importance of having a functional reserve during physiologic stress.

The Effects of L-Carnitine Supplementation During Concurrent Training on the Functional Capacities and Body Composition in Obese Men

Abstract Background Despite extensive research, the effects of L-carnitine supplementation in treating obesity are still unclear and equivocal. L-carnitine transports fatty acids into mitochondria for oxidation and is marketed as a weight loss supplement. The purpose of the present research is to investigate the efficacy of L-carnitine during concurrent training on the functional capacities and body composition in obese men. Methods Thirty nonactive, obese males (age = 37.2 ± 1.5 years; body mass index = 33.8 ± 2.5 kg/m2) participated in this research. The participants were randomly divided into three groups: experimental group 1 (EXP1)—concurrent training with L-carnitine supplementation; experimental group 2 (EXP2)—L-carnitine supplementation without training; and control group—without training or L-carnitine supplementation. Concurrent training was performed for 8 weeks, three sessions per week, with a training intensity ranging from 60 to 75% of the maximum heart rate reserve and one-repetition maximum. Both experimental groups were supplemented with 35 mg L-carnitine supplement per kilogram body weight. Various functional and body composition variables were collected at three time points (pre-test, mid-test, and post-test). Results A number of variables were significantly improved in EXP1 after 4 and 8 weeks (systolic blood pressure, maximal oxygen consumption, weight, body mass index, and one-repetition maximum) and only after 8-weeks (diastolic blood pressure, resting heart rate, percentage of body fat, and fat-free mass). No significant changes were observed for EXP2 and the control group. Conclusion L-carnitine supplementation, in conjunction with concurrent training, emerges as a highly effective approach for enhancing body composition and boosting functional capacities in obese adult men. Therefore, it is recommended that overweight male individuals integrate concurrent training into their regimen while taking L-carnitine.

Sprint Interval Training on Stationary Air Bike Elicits Cardiorespiratory Adaptations While Being Time-Efficient.

Moghaddam, M, Cervantes, M, Cheshier, B, and Jacobson, BH. Sprint interval training on stationary air bike elicits cardiorespiratory adaptations while being time-efficient. J Strength Cond Res 37(9): 1795-1801, 2023-Sprint interval training (SIT) refers to a set of brief intermittent exercises that are performed at maximal intensity. This study compared the effects of 2 SIT protocols (e.g., 10-5-SIT and 20-10-SIT) vs. moderate-intensity continuous training (MICT) on cardiovascular adaptations, using stationary air bikes. Thirty-two recreationally active individuals were randomly assigned to the 3 performance groups, such as 10-5-SIT (n = 11), 20-10-SIT (n = 10), and MICT (n = 11), to train 3 days per week for 4 weeks. Moderate-intensity continuous training included 30 minutes of cycling at 75% of maximal heart rate reserve, whereas the SIT protocols consisted of 3 sets of 8 intervals at all-out intensity. The 10-5-SIT and 20-10-SIT were performed with 10-second work:5-second rest and 20-second work:10-second rest, with 2.5- and 5-minute recovery periods between sets, respectively. A ramp protocol was used before and after the intervention via cycle ergometer to assess aerobic performance. Time to exhaustion (TTE), absolute V̇o2max (A-V̇o2max), relative V̇o2max (R-V̇o2max), and metabolic equivalents (METs) were measured and analyzed with 2-way mixed factorial analyses of variance (ANOVAs). In addition, total work (TW) during 12 sessions were recorded and analyzed with 1-way ANOVA. Significant (p < 0.05) differences were found for TW (10-5-SIT: 907.3 ± 332.0, 20-10-SIT: 1230.0 ± 188.1, and MICT: 2263.0 ± 896.9 calories) between groups. A significant main effect of time was observed for 10-5-SIT, 20-10-SIT, and MICT (p < 0.05) in TTE (increased by 7.3, 8.7, and 8.2%), A-V̇o2max (increased by 13.0, 11.8, and 13.6%), R-V̇o2max (increased by 12.6, 12.1, and 14.8%), and METs (increased by 12.7, 12.3, and 14.9%), respectively. Despite less volume and duration, both SIT protocols induced cardiorespiratory adaptations similar to MICT. These findings suggest that performing SIT on a stationary air bike is valuable because of time-efficiency and cardiorespiratory adaptations.

The Effect Of High-Intensity Exercise Training On Serum Calcium Of Female Combat Athletes

Purpose: Cell homeostasis is an essential factor in maintaining cellular health and intracellular mechanisms, which can also be associated with inflammatory factors and increased stress for muscle cell health. Calcium is also a necessary factor in cell health and is to establish homeostasis in the body. This study aimed to investigate the effect of high-intensity training on serum calcium levels in combat women. Method: For this purpose, 18 women karateka in the age range of 17 to 23 years were randomly divided into 2 groups: control (n=7) and exercise ((n=11). The exercise group performed proper exercises to improve karate and aerobic techniques for 6 weeks in the intensities of more than 80% of the maximum heart rate reserve. Physiological indices and blood samples were measured 24 hours before and 48 hours after the training protocol. To measure calcium cell biomarker, the Pars Azmoon calcium kit was used. Research data were analysed by covariance test at the significant level (P≤0.05) using SPSS software version 25. Results: After six weeks of high-intensity training, there was a significant difference in serum calcium levels in the exercise group compared to the control group (P = 0.002). Also, the results within the group showed a significant increase in serum calcium (P = 0.016) in the exercise group compared to baseline conditions. Conclusions: High intensity training seems to increase serum calcium in female athletes, and this can lead to precursors to cellular disorders, muscle damage and increase inflammatory factors and ultimately decrease the performance of female athletes. However, more research is essential in this regard.

CKD patients have augmented beat-to-beat BP variability that is not improved with 12 weeks of cycling exercise

Increased blood pressure (BP) variability is a powerful predictor of cardiovascular events and end-organ damage and is associated with sympathetic overactivity. Given the heightened cardiovascular (CV) risk in patients with chronic kidney disease (CKD), we hypothesized that patients with CKD would exhibit augmented resting beat-to-beat BP variability. Additionally, since aerobic exercise training exerts CV protective effects and has been shown to reduce resting sympathetic activity, we hypothesized that twelve weeks of aerobic exercise training would improve resting beat-to-beat BP variability in patients with CKD. In 25 sedentary patients with CKD stages III-IV [19 male/6 female, age: 62 ± 10 yr, 23 Black/2 White, systolic/diastolic BP: 130 ± 12/73 ± 9 mmHg, BMI: 31 ±7 kg/m 2 ] and 15 controls [11 male/4 female, age: 56 ± 11 yr, 13 Black/2 White, systolic/diastolic BP: 129 ± 12/83 ± 8 mmHg, BMI: 29 ± 3 kg/m 2 ], resting beat-to-beat blood pressure (finger photoplethysmography) was continuously measured for 5–10 min. Next, a subset of patients with CKD (n = 13) underwent 12 weeks of aerobic cycling exercise (spinning at 85% of maximal heart rate reserve). Exercise training was performed 45 minutes/session 3 days/week. All measurements were performed at baseline (n=40) and following the 12-week intervention (n=13). We calculated the standard deviation (SD), the coefficient of variation [CV (SD/mean)×100], and the average real variability (AVR) as indices of BP variability. Compared with controls, patients with CKD had significantly increased BP variability. The systolic SD BP (6.0 ± 2.1 vs. 3.9 ± 1.8 mmHg, P = 0.002) and the mean SD BP (3.9 ± 1 vs. 2.8 ± 1 mmHg, P = 0.006) were increased in CKD vs. Controls, but there were no differences in diastolic SD BP between groups (3.3 ± 1 vs. 2.6 ± 1 mmHg, P = 0.065). Similar results were found using AVR (Systolic AVR 2.0 ± 0.5 vs. 1.1 ± 0.5 mmHg, P &gt; 0.001 and, Mean AVR, 1.3 ± 0.5 vs. 1.0 ± 0.3 mmHg, P = 0.010 for patients with CKD and controls respectively). Contrary to our hypothesis, we observed no significant change in resting beat-to-beat BP variability after 12 weeks of exercise in patients with CKD (SD SBP 6.3 ± 2.1 vs. 5.7 ± 2.0 mmHg, P = 0.893 and, AVR 1.9 ± 0.5 vs. 1.9 ± 0.6 mmHg, P = 0.970). In summary, our data demonstrate that patients with CKD have augmented beat-to-beat BP variability, and 12 weeks of cycling exercise did not reduce resting beat-to-beat BP variability in CKD patients. This work was supported by National Institutes of Health Grants R01HL135183 and R61AT010457 (J.P). This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Prevalence and associated risk factors of musculoskeletal disorders (MSDs) and physiological stress among the female brick molders of West Bengal, India

Objective: Women play a significant role in the Indian economy and are regarded as the backbone of the brickfield industry where they face a variety of stressors that predispose them to increased risk of developing musculoskeletal disorders. The present study aimed to estimate the prevalence of upper limb musculoskeletal disorders and physiological stress compared to a control group. Methods: The Nordic Modified Questionnaire (NMQ) was completed by 85 women brick molders to assess feelings of discomfort (pain) in different parts of the body. Furthermore, the Rapid Upper Limb Assessment (RULA) posture analysis tool explored the risk of upper-limb musculoskeletal disorders (ULMSDs). Handgrip strength was also measured using a handgrip dynamometer, and cardiovascular stresses were assessed by measuring heart rate, blood pressure and lung function parameters. Results: The results of the study revealed that upper limb MSDs are a significant problem among women brick molders, primarily involving the hand (97.6%), shoulder (94.1%), wrist (72.9%) and fingers (56.5%). Subjective discomfort ratings among the brick molders indicated pain (96.5%), followed by tingling (90.6%), numbness (88.2%) and stiffness (61.2%) in their hands. The detailed analysis of the RULA score revealed that the upper arms, lower arms and wrists were high-risk areas for MSDs. Soon after completion of work, the participants experienced reductions in the hand-grip strength compared to the control group. Heart rate brick molders as higher in comparison to control group, just after the completion of work. However, there was no significant change in maximum Heart rate (HRmax) and Heart Rate Reserve (HRR) between the two groups, but significant associations were observed in net cardiac cost (NCC) and relative cardiac cost (RCC). Blood pressure measures were higher in the brick molders after work as well Conclusion: Women brick molders engaged continuously in highly repetitive hand-intensive jobs and suffered from discomfort in the upper extremities. The RULA posture analysis results indicated that the working posture of women brick molders were at high risk for MSDs, which requires changes immediately. Female brick molders also presented with reduced lung function values compared to the controls Findings of this study highlight the need for various ergonomic interventions that can be applied to improve the safety of the molders and workplace conditions of the brickfield during molding activities.

Study on neuropsychological and neurophysiological functions: acute effect of aerobic exercise training in sleep disturbed collegiates

This study aimed to investigate the acute effects of aerobic-exercise (AE) on neurophysiological-functions and neuropsychological-functions in sleep-disturbed collegiates. 32 eligible students were included in study. They completed 30 minutes of single bout of moderate AE (at 60–70% of maximal heart rate reserve). Pre and post training measures were tested for both, neurophysiological-functions by recording eventrelated- potential-P300 [P300-amplitude and P300-latency], and for neuropsychological-functions by administering neuropsychological-test-battery [Attention, Working-memory, Sensorimotor-speed and Executive-function (EF)]. In experimental group, statistically significant improvements were observed when analyzed for all 3 (group-by-time interaction, main-time, and main-group) effects in neurophysiological-functions. However, results were not significant for all neuropsychological-functions measures except for EF. Correlation-analysis demonstrated no association between neurophysiologicalfunctions and neuropsychological-functions except for post-intervention (p300-latency and attention). It is therefore can be concluded that acute bout of AE may be a promising approach to improve cognitivefunctions in sleep-disturbed collegiates, however long-lasting effects are still unclear.

Cost-Effectiveness of High-intensity Training vs Conventional Therapy for Individuals With Subacute Stroke

ObjectiveThis investigation estimated the incremental cost-effectiveness of high-intensity training (HIT) compared with conventional physical therapy in individuals with subacute stroke, based on the additional personnel required to deliver the therapy. DesignSecondary analysis from a pilot study and subsequent randomized controlled trial. SettingOutpatient laboratory setting. ParticipantsData were collected from individuals with locomotor impairments 1-6 months poststroke (N=44) who participated in HIT (n=27) or conventional physical therapy (n=17). InterventionsIndividuals performing HIT practiced walking tasks in variable contexts (stairs, overground, treadmill) while targeting up to 80% maximum heart rate reserve. Individuals performing conventional therapy practiced impairment-based and functional tasks at lower intensities (<40% heart rate reserve). Main Outcome MeasuresCosts were assessed based on personnel use with availability of similar equipment. Incremental cost-effectiveness ratios (ICERs) and cost-effectiveness acceptability curves were calculated for quality-adjusted life years (QALYs) derived from the Medical Outcomes Short Form-36 questionnaire and gains in self-selected speeds (SSSs). ResultsPersonnel costs were higher after HIT (mean, $1420±234) vs conventional therapy (mean, $1111±219), although between-group differences in QALYs (0.05 QALYs; 95% confidence interval [CI], 0.0-0.10 QALYs) and SSS (0.20 m/s; 95% CI, 0.05-0.35 m/s) favored HIT. ICERs were $6180 (95% CI, −$96,364 to $123,211) per QALY and $155 (95% CI, 38-242) for a 0.1 m/s gain in SSS. ConclusionsAdditional personnel to support HIT are relatively inexpensive but can add substantial effectiveness to subacute rehabilitation. Future research should evaluate patient factors that increase the likelihood of improvement to maximize the cost-effectiveness of treatment post stroke.

The Effect of Water Treadmill Exercise on Children with Attention Deficit Hyperactivity Disorder

Background Attention deficit hyperactivity disorder (ADHD) is one of the prevalent disorders in child psychiatry with the potential of damage to mental talent evolution process and socio-emotional skills. This study aimed to determine the effect of Water treadmill exercise on children with Attention deficit hyperactivity disorder (ADHD). Materials and Methods: This was an experimental study with pretest, posttest design which was done in Gorgan. Participants were 46 children (mean age = 9.45 ±0.5, male = gender) who were identified and selected based on diagnostic criteria in two stages and were randomly divided into experimental and control groups (n=23). The experimental group performed running on a Water treadmill for eight weeks with three sessions each week (24 sessions in total) and each session for 30 minutes. The exercise intensity was for 10 minutes 40-45% and 20 minutes 55-65% of the maximum heart rate reserve. All sessions begin with a brief warm-up, including light aerobic activity and dynamic, static stretching, and end with a cool-down. Disorder Levels were measured using the Conners’ Parent Rating Scale-Revised (CPRS-R), and diagnostic interviews. Data were analyzed using SPSS software version 22. Results: The results showed that after controlling the pretest levels, behavior problems, social problems, anxiety-shyness, psychosomatic, and the overall score of attention deficit hyperactivity disorder in the experimental group were significantly lower the posttest than the control group (p <0.05). Conclusion Based on the results, exercise interventions with Water treadmill for eight weeks effectively reduce the symptoms of attention deficit hyperactivity disorder in children and can be used as an appropriate intervention.

The effect of one bout submaximal endurance exercise on the innate and adaptive immune responses of hypertensive patients.

Changes in some of the immune system factors are associated with a risk of cardiovascular disease. Therefore, the purpose of this study was to investigate the effect of one-bout submaximal endurance exercise (OBSEE) on the innate and adaptive responses of hypertensive patients. From among 70 men with hypertension, 20 men (mean age: 60.25±4.59 years, Body Mass Index [BMI]: 29.57±3.68 kg/m2, and the maximal oxygen uptake [VO<inf>2max</inf>] 34.83±2.11 mL/kg/min) were chosen. The statistical sample performed OBSEE for 30 minutes and at 60-65% of the maximum heart rate reserve (MHRR). Blood sampling was performed to measure the response of immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin M (IgM), white blood cells (WBCs), neutrophil (NEUT), basophil (BASO), eosinophil (EO), monocyte (MONO) and lymphocyte (LYMPH) of hypertensive patients before and immediately after exercise. Plasma volume changes (PVCs) were also calculated in order to find out accurate effectiveness of exercise. Shapiro-Wilk test was used to normalize the research data. To analyze the data, paired sample t-test was used at significant level (P≤0.05). The hypothesis test was performed using SPSS software v. 19. The results after adjusting for PVCs showed that OBSEE significantly increased WBCs (P=0.001) in hypertensive patients. On the other hand, a significant decrease was observed in EO (P=0.001) and MONO (P=0.001) levels after OBSEE. Significant changes were not found in NEUT (P=0.072), BASO (P=0.106), LYMPH (P=0.440), IgA (P=0.382), IgG (P=0.245) and IgM (P=0.081) levels. It seems that OBSEE can reduce the risk of hypertension caused by elevated EO and MONO in hypertensive patients.

Vagal Threshold Determination during Incremental Stepwise Exercise in Normoxia and Normobaric Hypoxia.

This study focuses on the determination of the vagal threshold (Tva) during exercise with increasing intensity in normoxia and normobaric hypoxia. The experimental protocol was performed by 28 healthy men aged 20 to 30 years. It included three stages of exercise on a bicycle ergometer with a fraction of inspired oxygen (FiO2) 20.9% (normoxia), 17.3% (simulated altitude ~1500 m), and 15.3% (~2500 m) at intensity associated with 20% to 70% of the maximal heart rate reserve (MHRR) set in normoxia. Tva level in normoxia was determined at exercise intensity corresponding with (M ± SD) 45.0 ± 5.6% of MHRR. Power output at Tva (POth), representing threshold exercise intensity, decreased with increasing degree of hypoxia (normoxia: 114 ± 29 W; FiO2 = 17.3%: 110 ± 27 W; FiO2 = 15.3%: 96 ± 32 W). Significant changes in POth were observed with FiO2 = 15.3% compared to normoxia (p = 0.007) and FiO2 = 17.3% (p = 0.001). Consequentially, normoxic %MHRR adjusted for hypoxia with FiO2 = 15.3% was reduced to 39.9 ± 5.5%. Considering the convenient altitude for exercise in hypoxia, POth did not differ excessively between normoxic conditions and the simulated altitude of ~1500 m, while more substantial decline of POth occurred at the simulated altitude of ~2500 m compared to the other two conditions.

Effect of aerobic training with silymarin consumption on glycemic indices and liver enzymes in men with type 2 diabetes

This study investigated the effect of eight weeks of aerobic training (AT) combined with silymarin (S)consumption on glycemic indices and liver enzymes in men with type 2 diabetes (T2D). In this clinical trial, 60 middle-aged male volunteers were randomly divided into 4 groups, including: (1) C + placebo(C) (2) AT + placebo (3), S and (4) AT + S. AT was performed for eight weeks, three sessions per week, each session for 20–45 minutes at an intensity of 60–85% of maximal heart rate reserve, and S receiving groups consumed 140 mg/kg S daily (in two servings). AT reduced glycemic indices and liver enzymes in men with T2D (p ≤ .05). S decreased blood glucose, insulin, HOMA-IR, AST, ALT and ALP in men with T2D (p ≤ .05). Exercise along with silymarin decreased blood glucose, insulin, HOMA-IR, AST, ALT and ALP. Also, reduction of AST and blood glucose in the AT + S group was more favourable than the effect of S alone (p ≤ .05). It seems that simultaneous AT and S has interactive effects on reducing glycemic indices and liver enzymes in men with T2D.

The effect of moderate-intensity aerobic training on pulmonary function and estrogen receptor-alpha gene in postmenopausal women with vitamin D deficiency: A randomized control trial

BackgroundThe impact of aerobic training on pulmonary function by modulating gene expression of estrogen receptor-alpha (ERα), sex hormones and 25-hydroxy vitamin D (Vit D) in postmenopausal women (PMW) with Vit D deficiency is uncertain. ObjectiveThe purpose of this study was to examine the effect of 12 weeks of moderate-intensity aerobic training on pulmonary function, ERα gene expression, serum levels of sex hormones and Vit D in PMW with Vit D deficiency. MethodsTwenty-nine sedentary PMW with Vit D deficiency (aged 45-65 yrs) were randomized to exercise (EX, n = 15) and control (C, n = 14) groups. The EX group performed moderate-intensity aerobic training for 12 weeks (50-60 min/day, 3 days/week at 65-70% of maximal heart rate reserve), but the C group participated in no intervention and maintain their normal lifestyle during 12 weeks. The pulmonary function parameters, ERα gene expression, serum levels of sex hormones and Vit D were measured at baseline and week-12. ResultsAfter 12 weeks of aerobic exercise intervention, the increase in lymphocyte ERα gene expression (p = 0.005, estimate of effect size/Eta = 32.8%) and serum Vit D (p = 0.001, Eta = 54.7%) were significantly higher in the EX group compared to the C group, whereas pulmonary function parameters and sex hormones (17β-estradiol and progesterone) were not significantly different (P > 0.05). ConclusionsThe results suggested that 12 weeks of moderate-intensity aerobic training increased lymphocyte ERα gene expression as well as serum Vit D in sedentary PMW with Vit D deficiency although pulmonary function was not improved.

Effect of postprandial moderate-intensity walking for 15-min on glucose homeostasis in type 2 diabetes mellitus patients.

Diabetes patients usually have a low activity level and complain about lack of time. Therefore, we investigated the effect of short time, postprandial moderate-intensity exercise on glucose homeostasis in type 2 diabetes patients. Eleven patients with type 2 diabetes were recruited. Patients spent the first day of the study without exercise (non-exercise day; NE day). In the second day, they walked at moderate-intensity (40% of the maximum heart rate reserve) for 15min, 30min after each meal (exercise day; E day). Glucose homeostasis was estimated by a continuous glucose monitor (CGM). All meals during the study were of standard composition. We compared NE day and E day concerning 24-h glucose homeostasis and 3h postprandial glucose levels by the incremental area under the curve (iAUC) method. Medications were not changed during the study. The number of patients under basal supported oral therapy, intensive insulin therapy and oral hypoglycemic agents (OHA) were 5, 4 and 2, respectively. The blood glucose standard deviation over 24h and the iAUC for the 24-h glycemic variability (NE day vs. E day; 34,765 [21,424-56,014] vs. 23,205 [15,323-39,779]) were smaller in E day than in NE day. These results suggest that postprandial moderate-intensity walking, easily performable in daily life activities, was effective for improving glucose homeostasis. Further study should be performed to clarify the relationship between postprandial walk and drug therapy (insulin and OHA), including insulin secretory ability.

The effects of short-term moderate intensity aerobic exercise and long-term detraining on electrocardiogram indices and cardiac biomarkers in postmenopausal women

ObjectiveThe purpose of this study was to investigate the effects of 12-week of moderate-intensity aerobic exercise and 5-month detraining on electrocardiogram (ECG) indices and serum levels of 25-hydroxivitamin D (Vit D), parathyroid hormone (PTH), calcium (Ca2+), and phosphorus (P) in postmenopausal women (PMWs). Materials and methodsThirty-one PMWs (aged 50–70 yrs) were randomized to exercise (EX, n = 16) and control (C, n = 15) groups. EX group performed of 12-week of warm up- walking/jogging moderate intensity aerobic exercise training program- recovery (60 min/day, 3 days/week at 70% of maximal heart rate reserve), and then 5-month detraining remained. C group maintain their normal lifestyle during 8 months. The ECG indices and cardiac serum levels were measured at baseline, after 12-week exercise, and after 5-month detraining. ResultsAfter 12-week exercise intervention, P-R interval, serum PTH and serum Vit D were significantly increased in the EX group compared to the C group (P = 0.020, P = 0.001 and P = 0.001, respectively). After 5-month detraining, P-R segment and S-T interval were significantly decreased (P = 0.042 and P = 0.001, respectively) while serum Vit D was significantly increased (P = 0.014) in the EX group compared to the C group. ConclusionsThe results suggested that 12-week of moderate intensity aerobic exercise increased the P-R interval, PTH and Vit D, as severe Vit D deficiency status (below 10 ng/ml) improved to Vit D deficiency status (between 10 and 20 ng/ml) in PMWs. Also, long-term positive adaptations to aerobic exercise such as increased Vit D were observed even after 5-month detraining. In addition, P-R segment and S-T interval decreased after 5-month detraining in sedentary PMWs, which may be a sign of atrial positive adaptations to aerobic exercise.

Application of spiroergometry to determine work metabolism related strain in the course of cable work with a mini forestry crawler

ABSTRACT Winching is a common practice for extracting logs in forest operations; however, it requires significant physical effort by humans to pull-out the cable to the felling site. The aim of this study was to quantify the intensity of this activity by measuring human effort parameters during different winching operations under experimental conditions with a mini forestry crawler. Internal energy provision was determined by a portable spiroergometric device which was linked to beat-to-beat heart rate measurement. These data as well as the pulling force were assigned to the respective distance markers. After a small decrease over the first few meters, the pulling force increased as the pull-out distance increased. A maximum heart rate reserve of 67.3% and a metabolic equivalent (MET) of 11.6 were reached at the choking point in the flat winching direction. When winching was simulated uphill, peak values between 6.6 and 9.1 METs were reached at the end of the winching process. Winching with a remote-controlled mini forestry crawler over a distance of 50 m was rated as vigorous work, since METs of 6.0 for the entire work cycle were frequently exceeded. Thus, winching distances should be kept shorter in order to reduce metabolic strain. Moreover, winching teams should take active breaks and rotate work tasks during the working day to enable the necessary recovery.

398 Rate Pressure Product, Age-Predicted Maximum Heart Rate and Heart Rate Reserve: Which One Will Reign Supreme as a Predictor of Cardiovascular Events following Exercise Treadmill Testing?

398 Rate Pressure Product, Age-Predicted Maximum Heart Rate and Heart Rate Reserve: Which One Will Reign Supreme as a Predictor of Cardiovascular Events following Exercise Treadmill Testing?

Heart rate response during exercise predicts exercise tolerance in adults with transposition of the great arteries and atrial switch operation

BackgroundTo assess the relationship between heart rate response and exercise tolerance in adults with systemic right ventricle (sRV) after atrial switch repair for Transposition of the Great Artery (TGA) in addition to other physiological parameters. MethodsAll patients with a sRV after atrial switch repair for TGA followed in our institution between June 2015 and April 2018 who underwent cardiopulmonary exercise testing (CPET) were analyzed. Cardiac imaging performed within a six-month time period of the CPET were also collected. Chronotropic incompetence was defined as the inability to achieve 80% of age-predicted maximal heart rate reserve (HRR) and <62% on a beta-blocker regimen. Patient characteristics were assessed according to tertiles of the percentage of predicted pVO2 (%ppVO2). ResultsWe studied 70 patients (mean of age 32.4 ± 7.6 years old, 51 males). Mean peak oxygen uptake was 21.5 ± 5.8 mL/kg/min, corresponding to a %ppVO2 of 57 ± 14.1% while mean VE/VCO2 slope was 37.1 ± 8.2. There was a trend toward more exaggerated hyperventilation in patient with lower pVO2. Mean age-adjusted HRR was 68.5 ± 19%. Chronotropic incompetence was observed in 65.7% and was correlated with %ppVO2 (r = 0.482; p < 0.001) as physical training evaluated with Ventilatory Anaerobic threshold (r = 0.571; p < 0.001), while no difference was found based on respiratory parameters. No echocardiographic or Magnetic Resonance Imaging parameters assessing sRV systolic function at rest were correlated with %ppVO2. ConclusionsExercise limitation is related to the inability to increase cardiac output during exercise and is notably due to the degree of chronotropic incompetence.

Effects of acute aerobic and resistance exercise on executive function: An ERP study

ObjectivesThis study addressed the effects of acute, moderate-intensity aerobic and resistance exercise on the shifting aspect of cognition following a 30-min recovery period. It also explored the neuro-electrical activation that underlies the relationship between acute exercise and cognitive function through the examination of P3b and N1 components of event-related potentials. DesignA counterbalanced, repeated-measures experimental design. MethodsThirty-five volunteer young adults completed two experimental sessions (i.e., acute aerobic exercise (AE) and resistance exercise (RE), matched in terms of intensity, and one reading session (control). The AE entailed cycling at 60–70% of maximal heart rate reserve for 30min. In the RE session, participants performed seven exercises with two sets of 8–12 repetitions at 70% of 10-repetition maximum. Each participant's neuro-electrical activation was recorded 30min after each session while s/he completed the task-switching test. ResultsAfter the 30-min recovery period, both AE and RE elicited shorter response times in global switching (ηp2=0.24) and local switching (ηp2=0.16) were observed when compared to control. Additionally, larger P3b amplitudes (but not N1 amplitudes) were evident in global switching (ηp2=0.15) and local switching (ηp2=0.16), regardless of exercise modality. ConclusionsThe present findings suggest that acute exercise has positive effects on cognitive function. Exercise-induced alterations during the later stages of mental processing might result in superior performance. There were significant selective benefits in terms of brain function regardless of exercise modality.

Genetic Variation and Mood Response to Exercise in the TIGER Study (OR08-08-19)

ObjectivesOur primary objective is to determine how mood response to exercise is influenced by genetic variation, controlling for exercise quantity and quality. MethodsThe Training Interventions and Genetics of Exercise Response (TIGER) Study is a prospective cohort study, in which sedentary subjects (18–35y, <30 min/wk for 30d prior to enrollment) participated in a 15-week program, exercising within a prescribed (65–85% maximum heart rate reserve) target heart rate zone for 3 d/wk. Before and after each exercise session, a subset of subjects (n = 247) completed a 10 cm visual analog scale (VAS: 0–100) for four mood states: fatigue, tension, depression, and hunger. Multiple linear regression was performed to examine the association between variation in DRD2, BDNF, and FTO genes and change in mood state following exercise, controlling for gender, exercise duration, and intensity. ResultsExercise was associated on average with reduced feelings of fatigue (−3.18 ± 16.37), tension (−3.85 ± 12.97), and depression (−5.12 ± 8.20), and increased feelings of hunger (6.06 ± 10.54). Carriers of the major allele (A) in rs1362570 for the FTO gene experienced greater reductions in tension following exercise (AA or AG: −5.19 ± 1.08 vs GG: −1.16 ± 1.24, P < 0.02, respectively). Homozygotes for the major allele (A) in rs1799978 for the DRD2 gene displayed reduced feelings of tension in response to exercise, while those with one or more minor alleles reported increased tension (AA: −4.69 ± 0.89 vs AG or GG: + 2.25 ± 2.16, P < 0.005). Homozygotes for the major alleles in rs151948, rs1362570, and rs1799978 (for BDNF, FTO, & DRD2 genes, respectively) served as strong predictors for changes in feelings of tension following exercise, controlling for gender and exercise parameters (P < 0.001). Subjects with one or more minor alleles (A) in rs1800498 for DRD2 gene displayed greater increases in hunger in response to exercise (AA or AG: 7.17 ± 0.85 vs GG: 3.96 ± 1.09, P < 0.03). ConclusionsSpecific gene polymorphisms, exercise intensity, duration, and gender may influence, in part, the variable mood response to exercise. Funding SourcesFunding for this research was provided by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health Grant.