Heart rate variability—study in futsal athletes

Background The practice of high perfomance sports leads to alterations of the autonomic nervous system (ANS). The study of heart rate variability (HRV) resorting to the electrocardiogram (ECG) is a practical, efficient and non invasive tool that allows the monitorization of the cardiac-autonomic function in high perfomance athletes, exposing the physiological adaptations to repeated and intense physical exercise. To evaluate the resting heart rate variability of futsal players resorting to the electrocardiogram during the pre-season and competitive season. Methods The sample used in this study was composed of fifteen male futsal athletes, subjected to a resting electrocardiogram in supine position with the duration of 6 minutes, at two different moments. Results From the first to the second record heart rate variability, it was observed a significant decrease in heart rate from 66.53 ± 10.39 bpm to 61.50 ± 11.14 bpm (P < 0.05) and the indexes related to the activity of the parasympathetic nervous system (PNS), RMSSD, pNN50, HFnu did not present statistical significance (P > 0.05) despite the verified increased of absolute values from the first to the second evaluation. Conclusions We were able to observe a decrease in heart rate (HR), as well as, a tendency for elevated parasympathetic indexes and a vagal predominance from the first to the second moment of evaluation. The monitorization of heart rate variability can be useful to identify adaptations to competitive loads and, thus, planning adequate training loads for each athlete, avoiding the occurrence of lesions and fatigue and allowing an improvement in performance.

An Attempt to Predict Changes in Heart Rate Variability in the Training Intensification Process among Cyclists

Individual changes in resting heart rate variability (HRV) parameters were assessed in seven Polish cyclists during a training process consisting of: a six-week period (P1) of predominantly low- and moderate-intensity training (L-MIT) and a six-week period (P2) where the proportion of high-intensity interval training (HIT) increased. Daily recorded HRV parameters included high-frequency spectral power (HF), square root of the mean squared difference between successive normal-to-normal RR intervals (RMSSD), and standard deviation of normal-to-normal RR intervals (SDNN). In each training microcycle, the average values of HFav, RMSSDav, and SDNNav were calculated individually for each participant. In three cyclists, HF was higher in P2 compared to P1, whereas in one cyclist, HF was higher in P1 than in P2. Each of these four cyclists presented an individual correlation between the average daily duration HIT effort in training microcycles (HITav) and HFav. Cyclists with low baseline values of HRV parameters showed increased activity of the parasympathetic nervous system, while in the cyclist with high baseline values of HRV parameters, an opposite change was observed. In conclusion, changes in resting HRV parameters between period P1 and P2 can be individualised. In the investigated group, it was possible to predict how HRV would change as a result of training intensification on the basis of HRV baseline values.

Autonomic activity, posttraumatic and nontraumatic nightmares, and PTSD after trauma exposure

Background Nightmares are a hallmark symptom of posttraumatic stress disorder (PTSD). This strong association may reflect a shared pathophysiology in the form of altered autonomic activity and increased reactivity. Using an acoustic startle paradigm, we investigated the interrelationships of psychophysiological measures during wakefulness and PTSD diagnosis, posttraumatic nightmares, and nontraumatic nightmares. Methods A community sample of 122 trauma survivors were presented with a series of brief loud tones, while heart rate (HRR), skin conductance (SCR), and orbicularis oculi electromyogram (EMGR) responses were measured. Prior to the tone presentations, resting heart rate variability (HRV) was assessed. Nightmares were measured using nightmare logs. Three dichotomous groupings of participants were compared: (1) current PTSD diagnosis (n = 59), no PTSD diagnosis (n = 63), (2) those with (n = 26) or without (n = 96) frequent posttraumatic nightmares, and (3) those with (n = 22) or without (n = 100) frequent nontraumatic nightmares. Results PTSD diagnosis was associated with posttraumatic but not with nontraumatic nightmares. Both PTSD and posttraumatic nightmares were associated with a larger mean HRR to loud tones, whereas nontraumatic nightmare frequency was associated with a larger SCR. EMGR and resting HRV were not associated with PTSD diagnosis or nightmares. Conclusions Our findings suggest a shared pathophysiology between PTSD and posttraumatic nightmares in the form of increased HR reactivity to startling tones, which might reflect reduced parasympathetic tone. This shared pathophysiology could explain why PTSD is more strongly related to posttraumatic than nontraumatic nightmares, which could have important clinical implications.

An external telemetry system for recording resting heart rate variability and heart rate in free-ranging large wild mammals

Measures of heart rate variability (and heart rate more generally) are providing powerful insights into the physiological drivers of behaviour. Resting heart rate variability (HRV) can be used as an indicator of individual differences in temperament and reactivity to physical and psychological stress. There is increasing interest in deriving such measures from free ranging wild animals, where individuals are exposed to the natural and anthropogenic stressors of life. We describe a robust, externally mounted heart rate monitor for use in wild mammals, deployed here on wild breeding adult female grey seals (Halichoerus grypus), that delivers millisecond precise measures of inter beat intervals (IBIs), allowing computation of resting HRV parameters. Based on Firstbeat™ heart rate belts, our system allows for remote, continuous recording of IBI data from over 30 individuals simultaneously at ranges of up to 200m. We assessed the accuracy of the IBI data provided by the Firstbeat™ system using concurrent IBI data derived from in-field electrocardiogram (ECG) recordings. Bland-Altmann analyses demonstrated high correspondence between the two sets of IBI data, with a mean difference of 0.87±0.16ms. We used generalized additive mixed-effects models to examine the impact of the default Firstbeat™ software artefact correction procedure upon the generation of anomalous data (flats and stairs). Artefact correction and individual activity were major causes of flats and stairs. We used simulations and models to assess the impact of these errors on estimates of resting HRV and to inform criteria for subsampling relatively error free IBI traces. These analyses allowed us to establish stringent filtering procedures to remove traces with excessive numbers of artefacts, including flats and stairs. Even with strict criteria for removing potentially erroneous data, the abundance of data yielded by the Firstbeat™ system provides the potential to extract robust estimates of resting HRV. We discuss the advantages and limitations of our system for applications beyond the study system described here.

290 Depression, anxiety, and resting heart rate variability during sleep in a sample of active duty service members

Introduction Depression and anxiety are among the most prevalent mental health outcomes in the military population with rates ranging between 11% and 15% in Army active duty service members (ADSMs). Oftentimes both maladies are comorbid with insomnia and other sleep-related disorders. We explored the association between self-reported depression and anxiety levels and resting heart rate variability (HRV) metrics during sleep using a wearable device, the Oura ring. Methods We conducted a longitudinal, naturalistic assessment of fit-for-duty ADSMs (N=44; 21-40 years of age, 38 males) attending the Naval Postgraduate School. Depression was assessed by the Beck Depression Inventory; anxiety was assessed by the State-Trait Anxiety Inventory. HRV (average nightly HRV and average nightly HRVmaximal during sleep) was assessed with the Oura devices during a period of MD=8 days (range 8–18). Results The median BDI score was 5.50 (IQR=9.50; range 0–23). Most participants had minimal depression (36, 81.8%) with seven (16.9%) having mild depression and one (2.27%) moderate depression. The median state anxiety score was 29.5 (IQR=16.8; range 20 – 56), whereas the median trait anxiety score was 31.0 (IQR=15.8; range 21–56). Correlation analysis (Spearman’s rho) showed that lower depression and anxiety scores were associated with higher nightly HRV during sleep. Specifically, average nightly HRV was correlated with BDI scores (rho=-0.384, p=0.010), state anxiety scores (rho=-0.343, p=0.023), and trait anxiety (rho=-0.356, p=0.018). Average nightly HRVmaximal was negatively correlated with BDI scores (rho=-0.435, p=0.003), state anxiety scores (rho=-0.339, p=0.024), and trait anxiety (rho=-0.339, p=0.025). Conclusion Our findings suggest that HRV during sleep is associated with self-reported depression and anxiety levels in this sample of ADSMs. Further research is needed to assess the utility and limitations of the Oura devices to collect data in field settings. Support (if any):