Hemodynamic and Lactate Response to Exhaustive Exercise with L-Arginine Supplementation

Introduction: To further understand the effects of L-arginine on both its ability to enhance lactate clearance and increase overall blood flow before, during, and after exhaustive anaerobic exercise. Methods: Twelve healthy male subjects between the ages of 18-25 first completed an initial visit where baseline data was recorded. Subjects completed three additional visits, in which they ingested either a placebo, two-gram or four-gram dose of L-arginine. Blood flow (BF) and lactate were recorded before ingestion of the treatment, 5 and 15-minutes post-ingestion prior to performing a push-up test to volitional fatigue. Immediately following the push-up test, BF and lactate were assessed and again 15-minutes post exercise. Results: Blood lactate did not differ across condition (p=0.569). Lactate clearance was not influenced by L-arginine when analyzing the Area Under Curve. Blood flow increased with ingestion of the four-gram dose while at rest (the 15-minute mark). Blood flow was also enhanced in the four-gram dose immediately after exercise at the 25-minute mark. Conclusions: The data suggests that a four-gram dose of L-arginine plays a more significant role in blood flow than the clearance of lactate after exercise compared to a two-gram dose or placebo.

Enhancing Performance and Health Outcomes with Optimal Exercise and Nutrition Programming

Exercise and nutrition, when used as a mode to improve health outcomes is well-researched and accepted by researchers and clinicians, alike. Numerous health organizations have developed general recommendations such as physical activity and exercise to inform the public how to improve health outcomes. More often than not, these guidelines are vague and do not suggest how to achieve optimal health via exercise and nutrition. These guidelines also fail to consider physiological and psychological variability for patients and individuals aiming to follow such guidelines. For example, current recommendations include exercise intensities based on low, moderate, and vigorous activity and many people may not understand the physiological cost of such exercise intensities. Presently, accessible consumer-grade technology allows for accurate measurements of relative heart rate, exercise time, distance, and estimated caloric expenditure which is presumed easy for any person to understand. Therefore, creating guidelines that target specific and measurable variables, such as relative heart rate may be more advantageous for individualized health optimization.

Effects of a Single Dose of BURN-XT™ on Resting Metabolic Rate, Substrate Oxidation, and Various Indices of Affect

Introduction: Many consumers use dietary supplements in the hopes of increasing energy and burning more calories, which if sustained over time may help accelerate weight loss. The purpose of this clinical trial was to investigate the effects of an over-the-counter thermogenic supplement called Burn-XT™ (BXT) on metabolic rate, substrate oxidation, and various psychometric indices of affect that impact weight management. Methods: Using a double-blind, placebo-controlled, cross-over design, 16 women and 10 men (29.3 ± 7.3 yr, 169.4 ± 8.6 cm, 75.5 ± 14.3 kg) underwent two testing sessions: placebo (PL) and BXT. Seated metabolic rate and substrate oxidation, vital signs, and anchored visual analogue scale (VAS) assessments of energy, mood, motivation, focus, fatigue, concentration, and appetite were made before supplementation and hourly for three hours post-ingestion. Two-factor (2x4) factorial ANOVAs and paired sample t-tests (corrected for multiple comparisons) were used for analyses. Results: Significant increases in metabolic rate (oxygen consumption) were noted at 60 minutes in BXT (+11.9 mL O2/min) vs. PL (-2.5 mL O2/min), p = 0.004, d = -0.74. Only BXT increased metabolic rate compared to baseline at 60 minutes (+11.9 mL O2/min, p = 0.021, d = -0.53) and 120 minutes (+12.1 mL O2/min, p = 0.019, d = -0.54). The AUC for resting energy expenditure increased more in BXT vs. PL (p = 0.007, d = -0.57). VAS detected significant improvements in energy, mood, focus, and concentration for BXT vs. PL at 120 and 180 minutes (all p < 0.05, d = -0.58 to -0.68). In all cases, within-group changes from baseline for these VAS parameters were significant (all p < 0.05, d = -0.76 to -1.38) in BXT but not in PL. No within or between group differences in appetite, substrate oxidation, or heart rate were noted. Small (~3-4 mm Hg), but statistically significant (p < 0.05, d = -0.51 to -0.69) increases in diastolic blood pressure were noted in BXT at 60, 120, and 180 min vs. PL; and in systolic blood pressure at 60 min vs. PL. In all cases, values remained within normal clinical hemodynamic ranges. Conclusions: A single dose of BXT safely increased metabolic rate, energy, mood, focus, and concentration. Given that these factors are known to favorably impact weight management, future studies should determine whether daily supplementation with BXT reduces body weight and improves body composition.

Does Peripheral Lower Body Blood Flow Restriction Training Effect Aerobic Adaptations in Recreationally Active Adults? A Case Series

Introduction: Blood flow restriction (BFR) training is a novel training method that has been shown to promote positive aerobic and anaerobic adaptations under low intensity exercise by inhibiting blood flow to target tissue resulting in hypoxia and metabolic byproduct accumulation. This has been shown to have a direct positive effect on aerobic performance adaptation. The purpose was to explore the effect of BFR training on aerobic performance. Methods: Seven recreationally active adults were randomly assigned to either the BFR group (n=4, BFR) or non-BFR group (n=3, CON). Three testing sessions were conducted throughout the study (Pre-Test, Mid-Test, Post-Test) which consisted of a graded cycle ergometer maximum oxygen consumption (VO2max) test using COSMED-K5 indirect calorimetry. Eleven BFR training sessions were performed consisting of 20-min of cycling at 35-45% of heart rate reserve (HRR) with at 60% (BFR) or 5% (CON) arterial occlusion pressure (AOP) on the BFR cuffs. Results: Absolute VO2max, Relative VO2max, respiratory exchange ratio (RER), maximum heart rate (HRmax), and maximum rate of perceived exertion (RPEmax) reported no significant difference between BFR and CON. There was a significant difference (p < 0.05) found in time to reach VO2max and maximum watts (Wmax) reached which declined over the course of the training intervention. Conclusions: Bilateral lower limb aerobic BFR training resulted in no change in VO2max over seven weeks.

Remotely Supervised Home-Based Resistance Training and Orthostatic Tolerance in Young Physically Inactive Women During COVID-19

Introduction: Orthostatic intolerance (OI) is the inability of the cardiovascular system to adequately adjust to gravity upon standing, resulting in lightheadedness or syncope. OI can be characteristic of pathology (e.g. postural orthostatic tachycardia syndrome), which disproportionately affect women, and is compounded by inactivity. Thus, we tested the effects of remotely supervised home-based, 4-week resistance training (RT) program vs. control on the orthostatic stress response of previously inactive young females using the NASA Lean Test (NLT). Methods: Systolic (SBP) and diastolic (DBP) blood pressures, and heart rate (HR) were assessed during the NLT, pre- and post-training, along with fitness and body composition in females randomized to RT or control (n=7). Results: RT improved fitness (group*intervention, p=0.047) and fat-mass (-3.4±2.9 vs. +0.3±0.7Δlbs, p=0.037) over control. The NLT significantly altered SBP, DBP, and HR (all, p<0.01). For SBP, the interaction of group*intervention approached significance (p=0.071), lowering SBP in the RT group with the intervention. In DBP, the group*intervention was not significant (p=0.558). For HR, the group*intervention interaction approached significance (p=0.066). Conclusions: In the current study, short-term remotely-supervised RT using bands tended to decrease SBP and HR during orthostatic stress in young, otherwise healthy, previously inactive females, suggesting improved health but perhaps not orthostatic tolerance.

The Effects of Different Exercise Intensities and Modalities on Cortisol Production in Healthy Individuals: A Review

Cortisol is a hormone that is secreted in response to physiological stress. Exercise contributes significantly to changes in circulating cortisol concentrations. With exercise, there is increased activation of the sympathetic system to stimulate the release of adrenocorticotropic hormone, which releases cortisol into the blood. Current research has predominately studied the effects that aerobic exercise and resistance training have on cortisol production. Prolonged aerobic exercise, especially at higher intensities, significantly elevates cortisol concentrations when compared to similar duration and intensities of resistance exercise. Age, gender, physical fitness level, exercise intensity, training status, and modality are all variables that influence the production of cortisol. Elevated cortisol concentrations are highly indicative of muscle catabolism, increasing the loss of lean muscle tissue. This is a significant health concern for the growing elderly population. The rate of cortisol production changes as an individual ages and has been observed to have differing responses to exercise intensities in males and females. Cortisol production is correlated with exercise intensity and duration but does not increase the same across all exercise intensities. Higher exercise intensities and duration appear to be the main contributing factors that influence the production of cortisol, increasing the potential for muscle catabolism and muscle loss.

Differences in Energy Expenditure and Typing Speed While Sitting, Standing, and Walking in College Students

Introduction: The purpose of this study was to determine if caloric expenditure and typing speed differed among three positions (sitting, standing, walking). Methods: Participants included 40 college students (18-22 years, 30 males and 10 females) on either the baseball or track and field teams. Each participant was tested for 5 minutes in three different positions. Caloric expenditure was measured via indirect calorimetry and typing productivity via a 3-minute typing test. Repeated measures ANOVAs and T-Tests were performed to determine statistical differences for caloric expenditure and typing speed. Results: Caloric expenditure (calories per 5 minutes) was significantly higher for walking (16.4 ± 3.1) than for sitting (9.0 ± 2.4, p <0.0001) and standing (9.4 ± 2.0, p <0.0001). For typing productivity, standing resulted in faster typing speed than walking (37.4 ± 10.2 vs. 34.7 ± 10.7 wpm, p = 0096). Conclusions: Using a standup walking desk to type while working expends significantly more calories than typing while sitting or standing at a desk. However, typing speed was significantly higher while standing at a desk than while walking at a desk.

Iron Status and Dietary Patterns of Collegiate Female Distance Runners

Introduction: Iron is in oxygen transport which is important for athletic performance. Many female distance runners struggle to maintain adequate iron status through diet alone and rely on iron supplementation. Methods: Interviews were conducted with eight members of the Women’s Cross Country team at a Division I university to assess dietary patterns and behaviors related to iron status. This information, along with food records and serum ferritin levels, were analyzed qualitatively for trends with a focus on iron intake, total energy intake, and food components that enhance and inhibit iron absorption. Results: All participants took an iron supplement at the time of the study. All but one had experienced poor iron status currently or in the past. Most participants did not meet dietary iron, Vitamin E, or estimated energy requirements. Half of the participants expressed an attempt to increase iron intake in response to higher training loads. Half attempted to increase intake in response to a low ferritin result or iron deficiency symptoms. Conclusions: Consistently low energy and iron intake among participants indicated the likelihood of a relationship with poor iron status and/or reliance on supplementation. The most common motivation for increasing iron intake was the prevention of symptoms.

Comparison of Peak Aerobic Capacity Between the Treadmill and a Skiing Ergometer

Introduction: The Concept2 SkiErg is increasing in popularity and is widely used to provide a low impact total body workout. Because of these benefits, the SkiErg could be an ideal tool for fitness testing. Therefore, the purpose of this study was to compare VO2peak values elicited from a treadmill (TM) and SkiErg (SE) graded exercise test (GXT). Methods: Twenty-two averagely fit females completed 2 GXT protocols to volitional exhaustion on a TM and SE. Peak VO2, HR, VE, TTE, and RER were compared using paired-samples t-tests with significant differences at p≤0.05. Max RPE was compared using a Wilcoxon Signed Rank Test. Results: TM was significantly greater than SE for VO2peak (43.82±1.07 vs 33.97±5.01 ml/kg/min, p<0.01), HR (189±8 vs 182±11 bpm, p<0.01), RPE (18.91+1.11vs 17.26+2.03, p=0.02), VE (95.44±11.26 vs 86.21±2.90 L/min, p=0.015), and TTE (550.16+137.56 vs 391.86±81.20 sec, p<0.01). RER was significantly greater on the SE (1.16±0.08 vs 1.12±0.06, p=0.024). Conclusion: Results suggest that TM elicits higher max values for VO2, HR, TTE, VE, and RPE compared to SE, while SE elicits a higher RER in the current population. SE could be used as an alternative mode of testing in averagely-fit females but does not directly compare to TM values.

Highly Branched Cyclic Dextrin and its Ergogenic Effects in Athletes: A Brief Review

Highly branched cyclic dextrin (HBCD) is a relatively new carbohydrate source that has gained much popularity in sports nutrition supplements, quickly becoming one of the most popular sports and fitness supplements globally. Due to its high molecular weight and low osmolality, HBCD is thought to provide an ergogenic advantage over other carbohydrate sources via faster gastric emptying and faster absorption. The purpose of this brief review is to explore performance claims and implications of HBCD use. We provide rationale for recommended use based on results of scientific studies conducted in both animals and humans.