Autonomic and Perceptual Responses to Induction of a Ketogenic Diet in Free-Living Endurance Athletes: A Randomized, Crossover Trial

2020 ◽  
pp. 1-7
Author(s):  
Ed Maunder ◽  
Deborah K. Dulson ◽  
David M. Shaw
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Exercise Capacity ◽  
Ketogenic Diet ◽  
Physiological Stress ◽  
Endurance Performance ◽  
Endurance Athletes ◽  
Recovery Stress ◽  
Individual Level ◽  
Dietary Shift

Purpose: Considerable interindividual heterogeneity has been observed in endurance performance responses following induction of a ketogenic diet (KD). It is plausible that a physiological stress response in the period following the dramatic dietary shift associated with transition to a KD may explain this heterogeneity. Methods: In a randomized, crossover study design, 8 trained male runners completed an incremental exercise test and ran to exhaustion at 70%VO2max before and after a 31-day rigorously controlled habitual diet or KD intervention, and recorded heart rate variability (root mean square of the sum of successive differences in R–R intervals [rMSSD]) upon waking each morning along with the recovery–stress questionnaire for athletes each week. Data were analyzed using linear mixed models. Results: A significant reduction in rMSSD was observed in the KD (−9.77 [4.03] ms, P = .02), along with an increase in day-to-day variability in rMSSD (2.1% [1.0%], P = .03). The reduction in rMSSD in the KD for the subgroup of individuals exhibiting impaired exercise capacity following induction of the KD approached significance (Δ −22 [15] ms, P = .06, N = 4); whereas no effect was observed in those who exhibited unchanged exercise capacity (Δ 5 [18] ms, P = .61, N = 4). No main effects were observed for recovery–stress questionnaire for athletes. Conclusions: Our data suggest those working with endurance athletes transitioning onto a KD may consider using noninvasive, inexpensive resting heart rate variability measures to gain individual-level insights into the likely short-term effects on exercise capacity.

scholarly journals Predictive Value of Subacute Heart Rate Variability for Determining Outcome Following Adolescent Concussion

2021 ◽  
Vol 10 (1) ◽  
pp. 161
Author(s):  
Colt A. Coffman ◽  
Jacob J. M. Kay ◽  
Kat M. Saba ◽  
Adam T. Harrison ◽  
Jeffrey P. Holloway ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Cognitive Performance ◽  
Predictive Value ◽  
System Integration ◽  
Sports Medicine ◽  
Clinical Symptoms ◽  
Physiological Stress ◽  
Neurological Dysfunction ◽  
Neurobehavioral Function

Objective assessments of concussion recovery are crucial for facilitating effective clinical management. However, predictive tools for determining adolescent concussion outcomes are currently limited. Research suggests that heart rate variability (HRV) represents an indirect and objective marker of central and peripheral nervous system integration. Therefore, it may effectively identify underlying deficits and reliably predict the symptomology following concussion. Thus, the present study sought to evaluate the relationship between HRV and adolescent concussion outcomes. Furthermore, we sought to examine its predictive value for assessing outcomes. Fifty-five concussed adolescents (12–17 years old) recruited from a local sports medicine clinic were assessed during the initial subacute evaluation (within 15 days postinjury) and instructed to follow up for a post-acute evaluation. Self-reported clinical and depressive symptoms, neurobehavioral function, and cognitive performance were collected at each timepoint. Short-term HRV metrics via photoplethysmography were obtained under resting conditions and physiological stress. Regression analyses demonstrated significant associations between HRV metrics, clinical symptoms, neurobehavioral function, and cognitive performance at the subacute evaluation. Importantly, the analyses illustrated that subacute HRV metrics significantly predicted diminished post-acute neurobehavioral function and cognitive performance. These findings indicate that subacute HRV metrics may serve as a viable predictive biomarker for identifying underlying neurological dysfunction following concussion and predict late cognitive outcomes.

249 Overnight heart rate variability depends on age, gender, and day of the week: a field observation using a smart bed platform

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A100-A101
Author(s):  
Shawn Barr ◽  
Kwanghyun Sohn ◽  
Gary Garcia
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Physiological Stress ◽  
Large Population ◽  
Population Level ◽  
Large Set ◽  
Sleep State ◽  
Cross Sectional ◽  
Day Of The Week ◽  
Broad Interest

Abstract Introduction Heart rate variability (HRV) is commonly used to assess the activity of the autonomic nervous system (ANS). ANS function changes, reflected in HRV, result from factors including lifestyle, aging, cardiorespiratory illnesses, sleep state, and physiological stress. Despite broad interest in HRV, few studies have established normative overnight HRV values for a large population. To better understand population level HRV changes, ecologically-valid, overnight sleep SDNN (standard deviation of all normal heartbeat intervals, lower HRV is reflected by lower SDNN) values have been analyzed for a large sample of Sleep Number 360 smart bed users. Methods Overnight SDNN values were obtained over the course of 18.2M sleep sessions from 379,225 sleepers (48 ± 14.7 sessions/user). 50.9 percent of sleepers were female. The age was normally distributed with mean ± SD of 52.8 ± 12.7 years (range 21 to 84). Heartbeat intervals used to compute SDNN were extracted from a ballistocardiogram (BCG). BCG-based HRV estimation during sleep has previously been validated against ECG-based HRV with an R-square of 0.5. Results Using a Generalized Linear Model, significant cross-sectional associations with SDNN were observed for three variables of interest: age, gender, and day-of-the-week. For sleepers under 50, SDNN declined at a rate of about 2.1 ms/year, then leveled off for sleepers aged 50-65, and increased slightly thereafter. Women under 50 displayed lower, more slowly declining, SDNN values than men, but this trend reversed for sleepers over 50. Throughout the week, SDNN values followed a U-shaped (women) or L-shaped (men) pattern, where values were highest during the weekend and lowest at mid-week. Conclusion Using a smart bed to unobtrusively measure overnight SDNN values for a large set of sleepers in an ecologically valid environment, reveals significant effects of age, gender, and day of the week on overnight SDNN. Support (if any):

Heart rate variability in middle-aged sprint and endurance athletes

2019 ◽  
Vol 205 ◽  
pp. 39-43 ◽  
Author(s):  
Lysleine Alves Deus ◽  
Caio Victor Sousa ◽  
Thiago Santos Rosa ◽  
José Morais Souto Filho ◽  
Patrick Anderson Santos ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Endurance Athletes ◽  
Middle Aged

scholarly journals Relationship Between Morning Heart Rate Variability and Creatine Kinase Response During Intensified Training in Recreational Endurance Athletes

2018 ◽  
Vol 9 ◽  
Author(s):  
Matthias Weippert ◽  
Martin Behrens ◽  
Anett Mau-Moeller ◽  
Sven Bruhn ◽  
Kristin Behrens
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Creatine Kinase ◽  
Endurance Athletes

Heat Stress Training Camps for Endurance Sport: A Descriptive Case Study of Successful Monitoring in 2 Ironman Triathletes

2020 ◽  
Vol 15 (1) ◽  
pp. 146-150
Author(s):  
Ed Maunder ◽  
Andrew E. Kilding ◽  
Christopher J. Stevens ◽  
Daniel J. Plews
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Heat Stress ◽  
Well Being ◽  
Self Report ◽  
Endurance Athletes ◽  
Resting Heart Rate ◽  
Resting Heart Rate Variability ◽  
Stress Training

A common practice among endurance athletes is to purposefully train in hot environments during a “heat stress camp.” However, combined exercise-heat stress poses threats to athlete well-being, and therefore, heat stress training has the potential to induce maladaptation. This case study describes the monitoring strategies used in a successful 3-week heat stress camp undertaken by 2 elite Ironman triathletes, namely resting heart rate variability, self-report well-being, and careful prescription of training based on previously collected physiological data. Despite the added heat stress, training volume very likely increased in both athletes, and training load very likely increased in one of the athletes, while resting heart rate variability and self-report well-being were maintained. There was also some evidence of favorable metabolic changes during routine laboratory testing following the camp. The authors therefore recommend that practitioners working with endurance athletes embarking on a heat stress training camp consider using the simple strategies employed in the present case study to reduce the risk of maladaptation and nonfunctional overreaching.

Classification of Individuals Based on Autonomic Response to Virtual Gaming

2020 ◽  
Vol 17 (9) ◽  
pp. 4385-4393
Author(s):  
S. Chandana ◽  
B. R. Purnima ◽  
Prabhu Ravikala Vittal
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Physiological Stress ◽  
Rio Grande ◽  
The Body ◽  
Autonomic Response ◽  
Autonomic Nervous ◽  
Non Invasive

Modern games consists of digital gaming consoles that involves interaction with a user and has an interface to generate visual feedback through 2D/3D monitor. These games have several psychological side effects like loss of spatial awareness, back pains, insomnia, addiction, aggression, stress, and hypertension. Virtual reality (VR) Gaming is one of the most emerging and novel technologies in the field of entertainment. Evaluation of this new technology has become important in order to analyze the effects of its predecessors (2D and 3D gaming). The main focus of this paper is on detection of stress levels in individuals due to VR gaming and classify them depending on their sympathetic and parasympathetic dominance. This is done through acquisition of electrocardiogram (ECG) and photo plethysmograph signals (PPG) signals and extracting their time domain and frequency domain features before, during and after gaming (Fatma Uysal and Mahmut Tokmakçi, 2018. Evaluation of stress parameters based on heart rate variability measurement. Department of Biomedical Engineering, Erciyes University, Kayseri, Turkey. [email protected], [email protected]., da Silva1, A.G.C.B., Arauj, D.N., et al, 2018. Increase in perceived stress is correlated to lower heart rate variability in healthy young subjects. Departamento de Fisioterapia, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil. s/n., 81531–980, Curitiba, Parana, Brazil. E-mail: [email protected].). The physiological signal variation is analyzed by performing Heart Rate Variability (HRV) analysis over ECG signals which is one of the fast emerging methods in non-invasive research and clinical tools for assessing autonomic nervous system function (Juan Sztajzel, 2004. Heart rate variability: Aa non-invasive electrocardiographic method to measure the autonomic nervous system. Cardiology Center and Medical Policlinics, University Hospital, Geneva, Switzerland, SWISS MED WKLY 2004;134:514–522. www.smw.ch). Pulse-transmissiontime-variability (PTTV), which is extracted, has high coherence with heart rate variability and is also used as an objective measure of stress. In this paper we obtain the response of an individual during VR gaming and correlate them with the HRV/PTT parameters. The game chosen for the data acquisition was ‘VR city view rope crossing-360 android VR,’ during which data recording is done. It was found that there was a quantitative increase in physiological stress when individuals were exposed to virtual high heights in comparison with time relative to unaltered viewing. Mean Heart rate showed a significant increase during gaming for both boys and girls which indicates that the body is under the influence of a sympathetic activity like a physical exercise.

Heart Rate Variability and Exercise Capacity in Diabetic and Non-Diabetic Kidney Transplant Recipients

2004 ◽  
Vol 36 (Supplement) ◽  
pp. S250-S251
Author(s):  
Patricia A. Cowan ◽  
Ann K. Cashion ◽  
Richard Kreider ◽  
A. Osama Gaber ◽  
Donna K. Hathaway
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Kidney Transplant ◽  
Exercise Capacity ◽  
Transplant Recipients ◽  
Kidney Transplant Recipients ◽  
Diabetic Kidney

scholarly journals Effects of HRV-Guided vs. Predetermined Block Training on Performance, HRV and Serum Hormones

2017 ◽  
Vol 38 (12) ◽  
pp. 909-920 ◽  
Author(s):  
Olli-Pekka Nuuttila ◽  
Aku Nikander ◽  
Dmitry Polomoshnov ◽  
Jari Laukkanen ◽  
Keijo Häkkinen
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Aerobic Training ◽  
Endurance Performance ◽  
Serum Testosterone ◽  
Countermovement Jump ◽  
Running Performance ◽  
Testosterone Levels ◽  
Neuromuscular Performance ◽  
Serum Hormone

AbstractThe aim of this study was to compare heart rate variability -guided (HRVG) and predetermined (PD) block periodization of high intensity aerobic training (HIT). Endurance performance, neuromuscular performance, heart rate variability (HRV) and serum hormone concentrations were measured before, in the middle and after the 8-week training period in 24 endurance trained males. Both groups improved significantly maximal treadmill velocity (Vmax) (p<0.001) and 3000 m running performance (HRVG; p<0.001 and PD; p=0.001). The relative changes in Vmax and countermovement jump were significantly greater in HRVG (p<0.05). Nocturnal heart rate decreased in both groups (p<0.01), but HRV (RMSSD, LF and TP) increased significantly only in HRVG (p<0.05). The significant increase in serum testosterone concentration was observed from mid to post in HRVG (p<0.05). Significant correlations were found between individual Vmax changes and absolute serum testosterone levels. Individual baseline level of HF correlated significantly with Vmax changes in PD. Block periodization of HIT seems to be an effective way to improve endurance and running performance in already endurance trained males. Based on training induced increases in endurance and neuromuscular performance combined with significant changes in HRV and serum testosterone levels observed in HRVG, individually HRV -guided block training may be more optimal compared to predetermined training.

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