Low heart rate variability (bad) is associated with low Vitamin D and COVID – many studies

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Many devices costing ~$100 measure HRV

• https://goiheart.com/ measures blood oxygen Aortic Pulse Wave Velocity, and now HRV with iPad $150
  • Note:The founder of VitaminDWiki has been using this device since about 2018
• https://www.makevisible.com/ Free smartphone app that works with Polar Verity Sense armband
  • In Beta-testing as of Nov 2022 description
• The 6 Best HRV Monitors Of 2022 To Optimize Your Days (& Nights) updated Nov 2022
• 11 Best Heart Rate Variability Biofeedback Monitors (2022 Review & Comparison) Used by Pros - Dec 2022
• [https://help.elitehrv.com/article/119-why-can-t-i-use-my-wrist-hr-monitor-or-led-pulse-oximetry-monitors-like-fitbit|Why Watches and Wrist HR Monitors Usually Don't Work For HRV
  • ""Examples of devices that do not measure HRV include the Fitbit Charge HR, Mio wrist devices, Polar wristwatches, etc."
  • "There is no affordable hardware or sensor on the market that can measure accurate HRV from the wrist, arm, or hand using optical sensors or PPG while you are moving"

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Those with long-COVID had lower HRV - pre-print Nov 2022

Cardiac Autonomic Function in Long COVID-19 Using Heart Rate Variability: An Observational Cross-Sectional Study
preprints.org > medicine & pharmacology > cardiology > doi: 10.20944/preprints202211.0361.v1
Antonio da Silva Menezes Junior., Aline Andressa Schröeder , Silvia Marçal Botelho , Aline Lazara Resende

Background: Heart rate variability is a non-invasive, measurable, and established autonomic nervous system test. Long-term COVID-19 sequelae are unclear; however, acute symptoms have been studied.

Objectives: To determine autonomic cardiac differences between long COVID-19 patients and heathy controls and evaluate associations among symptoms, comorbidities, and laboratory findings. Methods: This single-center study included long COVID-19 patients and healthy controls. The heart rate variability (HRV), a quantitative marker of autonomic activity, was monitored for 24 h using an ambulatory electrocardiogram system. HRV indices were compared between case and control groups. Symptom frequency and inflammatory markers were evaluated. The significance level of 5% (p-value 0.05) was adopted.

Results: A total of 47 long COVID-19 patients were compared to 42 healthy controls. Patients averaged 43.8 (SD14.8) years old, and 60.3% were female. In total, 52.5% of patients had moderate illness. Post-exercise dyspnea was most common (71.6%), and 53.2% lacked comorbidities. COVID-19 patients had 4 times more dyslipidemia. CNP, D-dimer, and CRP levels were elevated (p-values of 0.0098, 0.0023, and 0.0015, respectively). The control group had greater SDNN24 and SDANNI (OR = 0.98 (0.97 to 0.99; p = 0.01)). Increased low-frequency (LF) indices in COVID-19 patients (OR = 1.002 (1.0001 to 1.004; p = 0.030)) and high-frequency (HF) indices in the control group (OR = 0.987 (0.98 to 0.995; p = 0.001)) were also associated.

Conclusions: Patients with long COVID-19 had lower HF values than healthy individuals. These variations are associated with increased parasympathetic activity, which may be related to long COVID-19 symptoms and inflammatory laboratory findings.
 Download the PDF from VitaminDWiki

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Both Vitamin D and Vitamin B12 improve HRV - Jan 2022

Association between Micronutrients and Heart Rate Variability: A Review of Human Studies
Advances in Nutrition, Volume 11, Issue 3, May 2020, Pages 559–575, https://doi.org/10.1093/advances/nmz136
Adrian L Lopresti

Heart rate variability (HRV) is a measure of the variation between consecutive heartbeats. It provides a marker of the interplay between the parasympathetic and sympathetic nervous systems, and there is an increasing body of evidence confirming an increased HRV is associated with better mental and physical health. HRV may be a useful marker of stress as it represents the ability of the heart to respond to a variety of physiological and environmental stimuli. HRV tends to decrease as we age and is positively associated with physical activity, fitness, and healthier lifestyles. The relation between HRV and micronutrients (vitamins and minerals) has also received some attention in the research literature. In this review, cross-sectional and interventional studies on human populations examining the relation between HRV and micronutrients are appraised.
Micronutrients identified and examined in this review include

• vitamins D, B-12, C, and E; the
• minerals magnesium, iron, zinc, and
• coenzyme Q10; and a
• multivitamin-mineral formula.

Due to the paucity of research and significant heterogeneity in studies, definitive conclusions about the effects of these micronutrients on HRV cannot be made at this time.
However, there is accumulating evidence suggesting deficiencies in vitamins D and B-12 are associated with reduced HRV, and zinc supplementation during pregnancy can have positive effects on HRV in offspring up until the age of 5 y. To further elucidate the relation between micronutrients and HRV, additional robustly designed and adequately powered studies are required.
 Download the PDF from VitaminDWiki

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Heart Rate Variability Parameters Indicate Altered Autonomic Tone in Patients with COVID-19 - May 2022

https://doi.org/10.1096/fasebj.2022.36.S1.R5349
Gabriel Gruionu, Anita Gupta, Megan Rattin, Thomas V. Nowak, Matthew Ward, Thomas H. Everett

The COVID-19 disease induces long term heart health complications and may induce autonomic nervous system dysfunction. Heart Rate Variability (HRV) is a measure of sympathetic (SNS) and parasympathetic (PNS) control of heart function. Recently, studies have shown that HRV analysis may be used as a predictor of COVID-19 symptoms and correlates with progression of the disease. We aimed to uncover the interplay between SNS and PNS in hospitalized COVID-19 patients at the time of admission and compare it with similar measurements in healthy patients (no comorbidities) and patients with cardiovascular disease. We hypothesized that COVID-19 would induce autonomic dysfunction similar to patients with cardiovascular disease (CVD). ECG telemetry recordings of 30-60 minutes in duration were acquired from patients that were admitted to Indiana University Health system hospitals for either COVID-19 complications or for complications associated with cardiovascular disease (CVD) states (arrhythmia, heart failure, coronary artery disease). In addition, 20-minute ECG Lead I recordings were obtained from healthy volunteers with no associated comorbidities. HRV parameters were calculated during sinus rhythm in the time, frequency, and nonlinear domains from the ECG telemetry recordings. The patient population was composed of 50 COVID-19 patients (average age 63, range 26-94), 32 healthy (average age 32.7, range 17-69) and 49 patients with cardiovascular disease (average age 65.4, range 30-88) as control groups. The COVID-19 group had a higher percentage of patients with BMI>30 (obese) than the control groups (55% vs 36%). Also, the COVID-19 and CVD patients had significantly higher heart rate and time-domain HRV parameters (including SDRR, RMSSD, SDSD) and SD1 in the non-linear domain when compared to healthy patients (88.8±53.0 and 87.9±55.2 vs 49.5±31.3, p<0.01). In the frequency domain, the LF/HF ratio was significantly lower in the COVID and CVD groups compared to healthy controls (0.5±0.76 and 0.55±0.50 vs 1.05±0.96, p<0.01). COVID-19 patients have significant HRV alterations which suggest increased vagal tone than in healthy volunteers but similar to patients with severe cardiovascular disease comorbidities. Even though the COVID patients had an increased heart rate, the results of the HRV analysis indicate increased vagal tone which would support autonomic nervous system dysfunction in these patients.
 Download the PDF from VitaminDWiki

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Impaired heart rate variability one and six months post acute COVID-19 - Oct 2022

European Heart Journal, Volume 43, Issue Supplement_2, Oct 2022, ehac544.402, https://doi.org/10.1093/eurheartj/ehac544.402S Lampsas, E Oikonomou, N Souvaliotis, A Goliopoulou, G A Papamikroulis, A Anastasiou, P Theofilis, G Zakynthinos, I Gialamas, P Pantelidis .

Background
Long COVID-19 syndrome is an increasingly recognized problem. Post-infectious cardiac autonomic dysfunction is commonly reported. This study aims to evaluate autonomic dysfunction by means of Heart rate variability (HRV) on post-COVID-19 patients.
Methods
Hospitalized patients for COVID-19 (either at the medical ward or Intensive Care Unit (ICU)) were followed up at 1 and 6 months after hospital discharge. Medical history and clinical information were collected. HRV was assessed by 24-hour ambulatory electrocardiography Holter, with the measure of the standard deviation of normal RR intervals in 24 h, ms (SDNN). The comparison was conducted with age and sex-matched non-COVID-19 controls.
Results
Thirty-four patients hospitalized with COVID-19 (20.6% admitted in ICU) were examined 1-month and 6-months post-hospital discharge. SDNN was significantly (p<0.001) reduced in the COVID-19 group (111±23 ms) compared to the control subjects (152±24 ms) 1-month after discharge. Subgroup analysis between COVID-19 group revealed that ICU subjects presented significantly (p<0.001) reduced SDNN compared to the medical ward, respectively (83±20 ms vs. 118±17 ms). At 6-months, an improvement was noted at SDNN 24h (6-month: 133±24 vs. control: 151±24 ms, p=0.004; 1-month: 111±23 ms vs. 6-month: 133±24 ms, p<0.001). Also at 6-months, ICU subjects noted significantly (p=0.003) reduced SDNN 24h compared to medical ward subjects (107±17 ms vs. 140±20 ms). On the 6-months follow-up, 32% of the subjects had “long-COVID-19” symptoms. Subjects with long COVID-19 symptoms had low SDNN values (“long-COVID-19”: 112±17 ms vs. non-“long-COVID-19”: 142±20 ms, p=0.001)
Conclusion
Patients hospitalized for COVID-19 have reduced SDNN, at one month post-hospital discharge which is improved at the six months follow-up. These findings emphasize the increased sympathetic drive activity in the post-acute COVID-19 phase and imply a link between autonomic dysfunction and long COVID-19.
 Download the PDF from VitaminDWiki

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HRV, COVID-19 and AI - March 2022

Heart rate variability as a marker of cardiovascular dysautonomia in post-COVID-19 syndrome using artificial intelligence
Indian Pacing and Electrophysiology J. vol 22, Issue 2, March–April 2022, pg 70-76 https://doi.org/10.1016/j.ipej.2022.01.004

Introduction
Cardiovascular dysautonomia comprising postural orthostatic tachycardia syndrome (POTS) and orthostatic hypotension (OH) is one of the presentations in COVID-19 recovered subjects. We aim to determine the prevalence of cardiovascular dysautonomia in post COVID-19 patients and to evaluate an Artificial Intelligence (AI) model to identify time domain heart rate variability (HRV) measures most suitable for short term ECG in these subjects.
Methods
This observational study enrolled 92 recently COVID-19 recovered subjects who underwent measurement of heart rate and blood pressure response to standing up from supine position and a 12-lead ECG recording for 60 s period during supine paced breathing. Using feature extraction, ECG features including those of HRV (RMSSD and SDNN) were obtained. An AI model was constructed with ShAP AI interpretability to determine time domain HRV features representing post COVID-19 recovered state. In addition, 120 healthy volunteers were enrolled as controls.
Results
Cardiovascular dysautonomia was present in 15.21% (OH:13.04%; POTS:2.17%). Patients with OH had significantly lower HRV and higher inflammatory markers. HRV (RMSSD) was significantly lower in post COVID-19 patients compared to healthy controls (13.9 ± 11.8 ms vs 19.9 ± 19.5 ms; P = 0.01) with inverse correlation between HRV and inflammatory markers. Multiple perceptron was best performing AI model with HRV(RMSSD) being the top time domain HRV feature distinguishing between COVID-19 recovered patients and healthy controls.
Conclusion
Present study showed that cardiovascular dysautonomia is common in COVID-19 recovered subjects with a significantly lower HRV compared to healthy controls. The AI model was able to distinguish between COVID-19 recovered patients and healthy controls.
 Download the PDF from VitaminDWiki

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Low HRV in hospital predicted 2X more likely to die of COVID - Oct 2021

Heart-rate-variability (HRV), predicts outcomes in COVID-19
PLOS x October 28, 2021 https://doi.org/10.1371/journal.pone.0258841
Maartje B. A. Mol , Maud T. A. Strous , Frits H. M. van Osch, F. Jeroen Vogelaar, Dennis G. Barten, Moshe Farchi, Norbert A. Foudraine, Yori Gidron

Background
Patients with COVID-19 present with a variety of clinical manifestations, ranging from mild or asymptomatic disease to severe illness and death. Whilst previous studies have clarified these and several other aspects of COVID-19, one of the ongoing challenges regarding COVID-19 is to determine which patients are at risk of adverse outcomes of COVID-19 infection. It is hypothesized that this is the result of insufficient inhibition of the immune response, with the vagus nerve being an important neuro-immuno-modulator of inflammation. Vagus nerve activity can be non-invasively indexed by heart-rate-variability (HRV). Therefore, we aimed to assess the prognostic value of HRV, as a surrogate marker for vagus nerve activity, in predicting mortality and intensive care unit (ICU) referral, in patients hospitalized with COVID-19.

Methods
A retrospective cohort study including all consecutive patients (n = 271) diagnosed and hospitalized with COVID-19 between March 2020 and May 2020, without a history of cardiac arrhythmias (including atrial and ventricular premature contractions), pacemaker, or current bradycardia (heart rate <50 bpm) or tachycardia (heart rate >110 bpm). HRV was based on one 10s ECG recorded at admission. 3-week survival and ICU referral were examined.

Results
HRV indexed as standard deviation of normal to normal heartbeat intervals (SDNN) predicted survival (H.R. = 0.53 95%CI: 0.31–0.92). This protective role was observed only in patients aged 70 years and older, not in younger patients. HRV below median value also predicted ICU referral within the first week of hospitalization (H.R = 0.51, 95%CI: 0.29–0.90, P = 0.021).

Conclusion
Higher HRV predicts greater chances of survival, especially in patients aged 70 years and older with COVID-19, independent of major prognostic factors. Low HRV predicts ICU indication and admission in the first week after hospitalization.
 Download the PDF from VitaminDWiki

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Low HRV may predict stroke and poor stroke outcome - June 2018

Heart Rate Variability as a Biomarker for Predicting Stroke, Post-stroke Complications and Functionality
https://doi.org/10.1177/1177271918786931
Ty Lees, Fatima Shad-Kaneez, …, and Sara Lal Sara.Lal at uts.edu.au+3View all authors and affiliations

Background:
Heart rate variability (HRV) is a non-invasive measure of the function of the autonomic nervous system, and its dynamic nature may provide a means through which stroke and its associated complications may be predicted, monitored, and managed.
Objective:
The objective of this review is to identify and provide a critique on the most recent uses of HRV in stroke diagnosis/management and highlight areas that warrant further research.
Methods:
The MEDLINE, CINAHL, and OVID MEDLINE databases were canvassed using a systematic search strategy, for articles investigating the use of HRV in stroke diagnosis and management. Initial paper selections were based on title alone, and final paper inclusion was informed by a full-text critical appraisal.
Results:
The systematic search returned 98 records, of which 51 were unique. Following screening, 22 records were included in the final systematic review. The included papers provided some information regarding predicting incident stroke, which largely seems to be best predicted by time- and frequency-domain HRV parameters. Furthermore, post-stroke complications and functionality are similarly predicted by time- and frequency-domain parameters, as well as non-linear parameters in some instances.
Conclusions:
Current research provides good evidence that HRV parameters may have utility as a biomarker for stroke and for post-stroke complications and/or functionality. Future research would benefit from the integration of non-linear, and novel parameters, the hybridisation of HRV parameters, and the expansion of the utilisation of predictive regression and hazard modelling.
 Download the PDF from VitaminDWiki

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HRV, autonomic dysfunction - Oct 2016

25-hydroxyvitamin d and its relationship with autonomic dysfunction using time- and frequency-domain parameters of heart rate variability in korean populations: a cross-sectional study.
Nutrients. 2014 Oct 16;6(10):4373-88. doi: 10.3390/nu6104373.
Tak YJ1, Lee JG2, Kim YJ3, Lee SY4, Cho BM5.

Previous studies have demonstrated that reduced heart rate variability (HRV) and hypovitaminosis D are associated with cardiovascular disease (CVD).
However, few reports have investigated the effects of vitamin D on HRV. This cross-sectional study analyzed serum 25-hydroxyvitamin D (25(OH)D) and HRV indices using 5-min R-R interval recordings with an automatic three-channel electrocardiography in healthy subjects (103 males and 73 females). Standard deviation of N-N interval (SDNN), square root of mean squared differences of successive N-N intervals (RMSSD), total power (TP), very low frequency (VLF), low frequency (LF), and high frequency (HF) were reported. The mean age of subjects was 55.3 ± 11.3 years and the mean 25(OH)D level was 21.2 ± 9.9 ng/mL. In a multiple linear regression model, 25(OH)D was positively correlated with SDNN (β = 0.240, p < 0.002), and LF (β = 0.144, p = 0.044).
Vitamin D deficiency (25(OH)D < 15 ng/mL) was associated with decreased SDNN (<30 m/s) (OR, 3.07; 95% confidence interval (CI), 1.32-7.14; p = 0.014) after adjusting for covariates. We found that lower 25(OH)D levels were associated with lower HRV, suggesting a possible explanation for the higher risk of CVD in populations with hypovitaminosis D.

 Download the PDF from VitaminDWiki.

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Impaired Cardiac Autonomic Functions in Apparently Healthy Subjects with Vitamin D Deficiency - Nov 2014

Ann Noninvasive Electrocardiol. 2014 Nov 2. doi: 10.1111/anec.12233.
Canpolat U1, Ozcan F, Ozeke O, Turak O, Yayla C, Açıkgöz SK, Cay S, Topaloğlu S, Aras D, Aydoğdu S.

OBJECTIVES:
Vitamin D (VitD) deficiency affects the cardiovascular system via endocrine, paracrine, and autocrine pathways. Limited data are available regarding cardiac autonomic dysfunction in VitD deficiency. The aim of this study was to assess the cardiac autonomic functions by using heart rate recovery index (HRRI) and heart rate variability (HRV) in apparently healthy subjects with VitD deficiency.

METHODS:
A total of 24 VitD deficient and 50 age-, gender-, and body mass index-matched VitD sufficient healthy participants who admitted to outpatient clinics at a tertiary centre were enrolled. All study participants underwent Treadmill exercise test and 24-hour Holter recording to assess cardiac autonomic functions. HRRIs were calculated by subtracting first, second, and third minute heart rates during recovery period from maximal heart rate.

RESULTS:
Mean HRR1 (28.0 ± 8.3 vs 42.8 ± 6.4, P < 0.001), HRR2 (41.1 ± 11.2 vs 60.8 ± 10.4, P < 0.001), and HRR3 (44.9 ± 13.3 vs 65.9 ± 9.8, P < 0.001) were significantly higher in VitD sufficient group compared to VitD deficient group. HRV parameters as, SDNN (P = 0.040), SDANN (P < 0.001), RMSSD (P < 0.001), PNN50 (P < 0.001), and HF (P < 0.001) were significantly decreased in patients with VitD deficiency; but LF (P < 0.001) and LF/HF (P = 0.003) were significantly higher in VitD deficient group. Serum 25(OH)D level was positively correlated with HRRIs (P < 0.001), PNN50, RMSSD, SDANN, and HFnu; negatively correlated with LFnu and LF/HF (P < 0.05). Also, multivariate linear regression analysis showed that serum 25(OH)D level was significantly associated with HRRIs and HRV parameters (P < 0.001).

CONCLUSION:
Our study results suggest that cardiac autonomic functions are impaired in patients with VitD deficiency despite the absence of overt cardiac involvement and symptoms. Further studies are needed to elucidate the prognostic significance and clinical implications of impaired autonomic functions in patients with VitD deficiency.

This study is in VitaminDWiki: Salmon intervention (vitamin D and Omega-3) improved heart rate variability and reduced anxiety – Nov 2014

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3+ VitaminDWiki pages have HEART RATE VARIABILITY in the title

This list is automatically updated

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Perhaps should add low HRV as an indicator of poor health - Oct 2023

MD Edge

• 30+ million Americans now have devices that measure HRV
• "Normal values (reference ranges) for HRV begin at an average of 100 msec in the first decade of life and decline by approximately 10 msec per decade lived. At age 30-40, the average is 70 msec; age 60-70, it’s 40 msec; and at age 90-100, it’s 10 msec."
  • Note: many PubMed studies have found exercise training increases senior HRV

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See also Heart Rate Variability: PubMed

• Heart rate variability for determining autonomic nervous system effects of lifestyle behaviors in early life: A systematic review 2020 - https://doi.org/10.1016/j.physbeh.2020.112806
  • "Increased HRV was significantly associated with higher maternal zinc and omega-3 fatty acid intake, regular maternal aerobic exercise and a non-smoking environment. "
• The association between vitamin D levels and heart rate variability in patients with type 2 diabetes mellitus - 2022 Aug 26. doi: 10.1097/MD.0000000000030263 FREE PDF
• Impact of Vitamin D supplementation on Heart Rate Variability in Vitamin D deficient Asthma COPD Overlap Syndrome patients: A Randomized Controlled Trial - Dec 2020 FREE PDF
• Early predictors of cardiac dysfunction in Egyptian children with chronic kidney disease - Jan 2019 doi: 10.4103/apc.APC_12_18 FREE PDF8
• Sarcopenia and Cardiac Dysfunction - May 2020 DOI: https://doi.org/10.1097/CRD.0000000000000285
• Association between Micronutrients and Heart Rate Variability: A Review of Human Studies - May 2020, https://doi.org/10.1093/advances/nmz136 FREE PDF
  • "..., there is accumulating evidence suggesting deficiencies in vitamins D and B-12 are associated with reduced HRV..."
• Research for correlation between heart rate variability parameters and bone mineral density in patients of type 2 diabetes mellitus - Aug 2022 https://doi.org/10.1007/s40618-022-01886-4

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