Andrew A. Flatt

Andrew A. Flatt
Georgia Southern University | GSU ·  Department of Health and Kinesiology

PhD

About

105
Publications
51,111
Reads
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1,594
Citations
Introduction
Andrew A. Flatt currently works at the Department of Health Sciences and Kinesiology, Georgia Southern University. Their current project is 'Heart Rate Variability and External Training Load Monitoring in Elite American Football Players Throughout a Preparatory and Competitive Season '.
Additional affiliations
August 2014 - present
University of Alabama
Position
  • Graduate Teaching and Research Assistant
April 2013 - August 2014
Auburn University in Montgomery
Position
  • Visiting Researcher and Adjunct Faculty

Publications

Publications (105)
Article
Full-text available
This case report demonstrates the effects of sport-related concussion (SRC) on heart rate variability (HRV) in an American college football player. Daily measures of resting, ultra-short natural logarithm of the root mean square of successive differences (LnRMSSD), subjective wellbeing, and Player Load were obtained each training day throughout a 4...
Article
We aimed to characterize cardiac-autonomic responses to a 13-day preseason camp in the heat among an American college football team. Players were categorized as linemen (n=10) and non-linemen (n=18). RHR, natural logarithm of the root-mean square of successive differences multiplied by twenty (LnRMSSD), and subjective wellbeing (LnWellness) were ac...
Article
Interindividual differences in training history may be a determinant of heart rate variability (HRV) profiles in collegiate sprint-swimmers and may account for differences observed between elite and subelite athletes. We therefore compared HRV profiles among national-level and conference-level sprint-swimmers while accounting for individual swim-tr...
Article
Full-text available
Purpose: To track cardiac-autonomic functioning, indexed by heart-rate variability, in American college football players throughout a competitive period. Methods: Resting heart rate (RHR) and the natural logarithm root mean square of successive differences (LnRMSSD) were obtained throughout preseason and ∼3 times weekly leading up to the nationa...
Article
Full-text available
Purpose: To report the impact of long-haul travel and the Olympic tournament on heart-rate variability and subjective well-being in a rugby sevens team. Methods: Players (N = 12 men) recorded daily root mean square of successive differences (LnRMSSD) and brief subjective well-being assessments before and throughout the Olympic tournament. Follow...
Article
In America, Black adults are 30% more likely to die from cardiovascular disease (CVD) compared to White adults, and more than half of this racial disparity in CVD-related mortality may be attributed to the substantially greater prevalence of high blood pressure (BP) in Black adults. Furthermore, compared to White adults with hypertension, Black adu...
Article
Stimuli that evoke pain stimulate the sympathetic nervous system leading to downstream vascular and hemodynamic adjustments. In clinical populations and older individuals, the perception of pain is associated with cardiovascular responses (e.g., heart rate, blood pressure, and arterial stiffness). However, there are extensive inter-individual diffe...
Article
Insufficiency or irregularity in sleep is associated with high blood pressure (BP) and aortic stiffness, both of which are independent predictors of all-cause and cardiovascular mortality. The cardiovascular ramifications of short and irregular sleep are well documented in shift workers, but the health implications of possible differences between s...
Article
Exercise-based cardiac rehabilitation may be an effective non-pharmacological intervention for improving endothelial function in coronary artery disease patients. Therefore, this systematic review with meta-analysis aimed to (a) estimate the training-induced effect on endothelial and vascular smooth muscle function, assessed by flow-mediated dilati...
Article
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El objetivo de este estudio fue analizar las oscilaciones de la actividad cardíaca parasimpática (ACP) en un mesociclo de una atleta keniata. La variabilidad de la frecuencia cardiaca (VFC) se midió durante tres semanas. En la primera semana (W1) el volumen de entrenamiento fue 120,55 km, en la segunda (W2) 96,71 km y en la tercera (W3) 79,45 km. S...
Article
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Background and purpose: Most studies on heart rate variability (HRV) in professional athletes concerned linear, time- and frequency-domain indices and there is lack of studies on nonlinear parameters in this group. The study aimed to determine the inter-day reliability, and group-related and individual changes of short-term symbolic dynamics (SymDy...
Article
Purpose: We compared physiological and perceptual responses to submaximal, moderate-vigorous, heart rate-based cycle ergometry with and without a fan. Methods: Sixteen recreationally active adults (25 ± 3 years; 8 men and 8 women) participated in the study. After an initial visit to assess cardiorespiratory fitness, each participant performed two 4...
Article
Background: The prevalence of mental health disorders is rising globally. Despite the popularity of exercise as a strategy to improve mental health in individuals with anxiety or depression, there is a paucity of literature on this topic in apparently healthy young individuals who are free from mental illness. Methods: We characterized relations...
Article
Full-text available
Purpose: This systematic review with meta-analysis was conducted to establish whether heart rate variability (HRV)-guided training enhances cardiac-vagal modulation, aerobic fitness, or endurance performance to a greater extent than predefined training while accounting for methodological factors. Methods: We searched Web of Science Core Collecti...
Article
Abstract We aimed to examine changes in resting heart rate variability, submaximal exercising heart rate (HRex), countermovement-jump height (CMJ), perceptual wellbeing, and internal load throughout preparatory training in elite women’s volleyball players. We also aimed to determine which HRV measurement position (supine vs. seated) provided greate...
Article
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Investigations into the sensitivity of heart rate‐ (HR) derived indices for tracking parasympathetic nervous system (PNS) changes in functionally overreached (F‐OR) endurance‐trained athletes have produced equivocal findings. Lack of clarity may be a result of methodological inconsistencies. Therefore, the aims of this systematic review and meta‐an...
Article
Introduction Insufficient sleep is an emerging risk factor for cardiovascular disease. To evaluate the hypothesis that decrements in vascular function, due to poor sleep, may serve as a mechanistic link between sleep and cardiovascular disease, we explored relationships of actigraphy-derived sleep metrics with central hemodynamics and arterial stif...
Article
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Background: Foam rolling (FR) is a self-myofascial release technique with unclear effects on autonomic functioning, indexed by heart rate variability (HRV). FR can be perceived as painful or relaxing, which may explain interindividual HRV responses. Purpose: To determine if acute FR alters resting HRV. A secondary aim was to determine if perceiv...
Article
Full-text available
Hydration practices may confound heart rate variability (HRV) measurements when collected in the pre-training period. We aimed to determine the effects of ingesting a hypertonic, sugar-sweetened sports beverage on HRV and hemodynamic parameters in physically active young men. Fifteen subjects consumed 591 mL of Gatorade (6% carbohydrate, ∼330 mOsmo...
Article
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Background: The association between heart rate variability (HRV), training load (TL), and performance is poorly understood. Methods: A middle-aged recreational female runner was monitored during a competitive 20-wk macrocycle divided into first (M1) and second mesocycle (M2) in which best performances over 10 km and 21 km were recorded. Volume (km)...
Article
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Purpose: To assess heart rate (HR) variability responses to various markers of training load, quantify associations between HR variability and fitness, and compare responses and associations between 1-minute ultrashort and 5-minute criterion measures among a girls' field hockey team. Methods: A total of 11 players (16.8 [1.1] y) recorded the log...
Article
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This study aimed to develop a predictive explanatory model for the 1,000-m time-trial (TT) performance in young national-level kayakers, from biomechanical and physiological parameters assessed in a maximal graded exercise test (GXT). Twelve young male flat-water kayakers (age 16.1 ± 1.1 years) participated in the study. The design consisted of 2 e...
Article
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Monitoring of markers reflecting cardiac autonomic activity before and during stressful situations may be useful for identifying the physiological state of an athlete and may have medical or performance implications. The study aimed to determine group and individual changes in short-term (5 min) and ultra-short-term (1 min) heart rate (HR), respira...
Article
Full-text available
We aimed to (a) evaluate the agreement between ultra-short-term and criterion resting heart rate variability (HRV) measures in military trainees, and (b) compare associations between HRV recording lengths and body composition. HRV recordings were performed for 10 min in 27 military male students. Mean RR interval, the root-mean square of successive...
Article
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Purpose: We aimed to 1) explore associations between changes in supine and standing heart rate variability (HRV) and submaximal exercising HR (HRex) and post-exercise HR recovery (HRR) variables 1 day post-high intensity interval training (HIIT), and 2) determine how baseline characteristics (e.g., aerobic fitness, HRV, etc.) associate with HRV res...
Article
Full-text available
Introduction Insufficient sleep is associated with arterial stiffness and elevated cardiovascular disease risk. Central hemodynamics are influenced by arterial stiffness, yet independently predict cardiovascular risk. Relationships between sleep characteristics and central hemodynamic parameters are largely unexplored. We aimed to characterize the...
Article
Purpose With the increasing popularity of ultra-short heart rate variability (HRV) measurements being utilized with mobile devices outside of controlled, research settings, it is important to determine the proper methodology to ensure accuracy. Therefore, the purpose of this study was to examine the validity of ultra-short-term HRV metrics across t...
Article
Background Insufficient sleep is associated with arterial stiffness and elevated cardiovascular disease risk. Central hemodynamics are influenced by arterial stiffness, yet independently predict cardiovascular risk. Relationships between sleep characteristics and central hemodynamic parameters are largely unexplored. We aimed to characterize the re...
Article
Full-text available
The aim of this study was to investigate the effect of recreational aerobic physical activity (PA) type and volume on heart rate variability (HRV) in Arab men. This was a retrospective, cross-sectional study, and included men (n = 75, age = 37.6 ± 7.1 years, body mass index (BMI) = 26.7 ± 3.1 kg/m 2) who were members of a walking group, cycling gro...
Article
Objectives The microbiota-gut-brain axis is an intricate communication network that is emerging as a key modulator of psychological and physiological wellbeing. Recent pioneering work in the field has suggested a possible link between gut microbiome composition with sleep, an evolutionarily conserved behavior demonstrated to play a critical role in...
Article
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Research on reliability of heart rate variability (HRV) parameters in athletes has received increasing attention. The aims of this study were to examine the inter-day reliability of short-term (5 min) and ultra-short-term (1 min) heart rate (HR), respiratory rate (RespRate) and HRV parameters, agreement between short-term and ultra-short-term param...
Article
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We quantified associations between changes in heart rate variability (HRV), neuromuscular and perceptual recovery following intense resistance training (RT). Adult males (n = 10) with >1 year RT experience performed six sets to failure with 90% of 10 repetition maximum in the squat, bench press, and pull-down. Changes (∆) from pre- to immediately (...
Article
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Objective: In two independent study arms, we determine the effects of strength training (ST) and high-intensity interval training (HIIT) overload on cardiac autonomic modulation by measuring heart rate (HR) and vagal heart rate variability (HRV). Methods: In the study, 37 well-trained athletes (ST: 7 female, 12 male; HIIT: 9 female, 9 male) were su...
Data
The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fphys.2019.00582/full#supplementary-material | Table 1.xlsx. Supplementary Tables. | Data Sheet 1.xlsx. Data Sheet. | Data Sheet 2.zip. Data analysis and statistical analysis. | Data Sheet 3.docx. Instructions heart rate recordin...
Data
Supplementary Figure 1. Standardized mean differences (d-diff) ... | Supplementary Figure 2. Correlations between performance and heart rate (variability) measures ... Strength Training ... | Supplementary Figure 3. Correlations between performance and heart rate (variability) measures ... HIIT ... | Supplementary Figure 4. Individual responses ......
Article
Full-text available
The purpose of this study was to analyze heart rate variability (HRV) oscillations before and after a marathon which involved trans-meridian air travel and substantial time zone differences in a professional wheelchair athlete with Charcot-Marie-Tooth (CMT) disease. The natural logarithm of the root mean square difference between adjacent normal R-...
Article
Objectives: The purpose of this study was to evaluate heart rate variability and athlete self-report measures of recovery status (ASRM) in response to consecutive domestic and international tournaments among an elite rugby sevens team. Design: Retrospective Methods: Olympic-level rugby sevens players (n = 10) recorded post-waking natural logarithm...
Article
Full-text available
Heart rate variability (HRV) is a physiological marker of training adaptation among athletes. However, HRV interpretation is challenging when assessed in isolation due to its sensitivity to various training and non-training-related factors. The purpose of this study was to determine the association between athlete-self report measures of recovery (...
Article
Objectives To evaluate weekly heart rate variability (HRV) responses to varying training load among an Olympic rugby sevens team and to assess whether HRV responses informed on training adaptation. Design Retrospective. Methods Natural logarithm of the root mean square of successive differences (LnRMSSD), psychometrics and training load from a ru...
Article
Full-text available
A systems modelling approach can be used to describe and optimise responses to training stimuli within individuals. However, the requirement for regular maximal performance testing has precluded the widespread implementation of such modelling approaches in team-sport settings. Heart rate variability (HRV) can be used to measure an athlete's adaptat...
Article
Full-text available
Sanz-Quinto, S, López-Grueso, R, Brizuela, G, Flatt, AA, and Moya-Ramón, M. Influence of training models at 3,900-m altitude on the physiological response and performance of a professional wheelchair athlete: A case study. J Strength Cond Res XX(X): 000-000, 2018-This case study compared the effects of two training camps using flexible planning (FP...
Article
Full-text available
Despite having to endure a rigorous in-season training schedule, research evaluating daily physiological recovery status markers among American football players is limited. The purpose of this study was to determine if recovery of cardiac-autonomic activity to resting values occurs between consecutive-day, in-season training sessions among college...
Article
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ABSTRACT Purpose: The primary purpose of this study was to determine the accuracy of the standard deviation of normal-to-normal intervals (SDNN) to root mean square of successive normal-to-normal interval differences (RMSSD) ratio from 1-minute recordings (SDNN:RMSSD1-min) compared to criterion recordings, as well as its relationship to low frequen...
Article
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The purpose of this study was to determine if recovery of cardiac-autonomic activity to baseline occurs between consecutive-day training sessions among positional groups of a collegiate football team during Spring camp. A secondary aim was to evaluate relationships between chronic (i.e., 4-week) HRV and training load parameters. Baseline HRV (lnRMS...
Poster
Full-text available
A hallmark sign of stress and inadequate recovery among athletes is an imbalance in autonomic nervous system activity, characterized by an elevated resting heart rate and reduced heart rate variability (HRV). Stress from training, competition, travel and academics can accumulate over the course of a football season, creating heightened potential fo...
Poster
Full-text available
Vagally-mediated heart rate variability (lnRMSSD) reflects cardiac-parasympathetic modulation and is commonly used as recovery status marker among athletes. Fitness level, body mass and physiological responses to training vary among positional groups in football. Thus, we hypothesize that lnRMSSD responses to training may also differ among position...
Article
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The purpose of this study was to determine the agreement between a smartphone pulse finger sensor (SPFS) and electrocardiography (ECG) for determining ultra-short-term heart rate variability in 3 different positions. Thirty college-aged men (n = 15) and women (n = 15) volunteered to participate in this study. Sixty-second heart rate measures were s...
Article
Full-text available
Heart rate variability has been widely used to monitor athletes’ cardiac autonomic control changes induced by training and competition, and recently shorter recording times have been sought to improve its practicality. The aim of this study was to test the agreement between the (ultra-short-term) natural log of the root-mean-square difference of su...
Article
Full-text available
Objectives: The purpose of this study was to evaluate cardiac-parasympathetic and psychometric responses to competition preparation in collegiate sprint-swimmers. Additionally, we aimed to determine the relationship between average vagal activity and its daily fluctuation during each training phase. Design: Observational. Methods: Ten Division-1...