Effects of COVID-19 lockdown on heart rate variability

The improvement effect of exercise on rats with chronic stress-induced depression-like behavior: a discussion based on the kynurenine pathway

OBJECTIVE

To observe the effects of 4 weeks of voluntary wheel running on depressive-like behavior in a rat chronic stress-induced depression model to explore the anti-depressive mechanism of exercise.

METHODS

In this observational study, 36 Sprague-Dawley rats were randomly divided into control, stress model, and stress exercise groups (12 rats/group). The control group received no intervention, and the stress model and stress exercise group rats underwent chronic mild unpredictable stress and isolation. The stress exercise group rats also underwent 4 weeks of voluntary wheel running. Behavioral changes and hippocampal protein and mRNA expression levels were detected.

RESULTS

Voluntary wheel running significantly increased horizontal and vertical movements, sucrose intake, and the sucrose preference percentage and reduced immobility time in the forced swimming test in depression model rats. The hippocampal tumor necrosis factor-α, interleukin (IL)-6, IL-1β, and quinolinic acid levels were significantly decreased, while the IL-4, IL-10, and kynurenic acid levels were significantly increased. Kynurenine-3-monooxygenase and 3-hydroxyanthranilate-3, 4-dioxygenase mRNA levels were downregulated, and kynurenine aminotransferase mRNA was upregulated.

CONCLUSION

Voluntary wheel running improved depressive-like behavior in depression model rats. The mechanism may be related to a kynurenine pathway metabolite level imbalance, which has neurotoxic and neuroprotective effects, caused by long-term voluntary wheel running.

Physiological evidence of stress reduction during a summer Antarctic expedition with a significant influence of previous experience and vigor

Antarctica provides a unique environment for studying human adaptability, characterized by controlled conditions, limited sensory stimulation, and significant challenges in logistics and communication. This longitudinal study investigates the relationship between stress indicators, with a specific focus on mean sleep heart rate, during a COVID-19 quarantine and subsequent 83 days long summer Antarctic expedition at the J. G. Mendel Czech Antarctic Station. Our novel approach includes daily recordings of sleep heart rate and weekly assessments of emotions, stress, and sleep quality. Associations between variables were analyzed using the generalized least squares method, providing unique insights into nuances of adaptation. The results support previous findings by providing empirical evidence on the stress reducing effect of Antarctic summer expedition and highlight the importance of previous experience and positive emotions, with the novel contribution of utilizing physiological data in addition to psychological measures. High-frequency sampling and combination of psychological and physiological data addresses a crucial gap in the research of stress. This study contributes valuable knowledge to the field of psychophysiology and has implications for expedition planners, research organizations, teams in action settings, pandemic prevention protocols, global crises, and long-duration spaceflight missions. Comprehensive insights promote the well-being and success of individuals in extreme conditions.

Impact of social isolation during COVID-19 on anthropometric data, quality of life, baseline physical activity and aortic pulse wave parameters in children and adolescents in two independent samples

BACKGROUND

The social restrictions resulting from the COVID-19 pandemic had a great impact on the routine of children and adolescents, with important consequences such as sleep, eating, and psychological/psychiatric disorders. Even though there are no studies on the subject, it is possible that these changes in habit and routine have also affected arterial stiffness (AS) in this population, which is an important predictor of cardiovascular risk. This study aimed to assess possible changes in AS, anthropometry, and quality of life (QoL) resulting from the COVID-19 pandemic in children and adolescents.

METHODS

A controlled observational cross-sectional study was performed with 193 children and adolescents aged 9 to 19 years, allocated into two groups: before the pandemic (BPG) and one year after the pandemic (APG), matched by age and sex. Cardiovascular parameters were measured non-invasively by brachial artery oscillometry with a portable device. The main AS indices evaluated were the augmentation index (AIx) and pulse wave velocity (PWV) derived from the aortic pulse wave. QoL was assessed using the Paediatric Quality of Life Inventory version 4.0 (PedsQL 4.0).

RESULTS

Regarding QoL, the APG showed a worsening in emotional (p = 0.002) and school-related (p = 0.010) aspects. There was no statistically significant difference for most anthropometric parameters, except for the hip circumference, which was higher in the APG group (p < 0.001). The main predictor of AS in the paediatric population, AIx@75, was shown to be increased in the APG group (p < 0.001). Other cardiovascular parameters were also different, such as peripheral (p = 0.002) and central (p = 0.003) diastolic blood pressure, stroke volume (p = 0.010), and total vascular resistance (p = 0.002), which were shown to be decreased in the APG group, while the heart rate was increased (p < 0.001).

CONCLUSIONS

Our results show that routine changes resulting from the period of social isolation increased cardiovascular risk in children and adolescents, evident by the increase in AIx@75, which is considered to be an important marker of cardiovascular risk in the paediatric population.

Efficacy of Yoga for COVID-19 Stress Prophylaxis

BACKGROUND

The global COVID-19 lockdown restricted daily routines due to the psychological fear of infection, which imposed an unknown universal threat on female college students, affecting physiological health and well-being. However, scant information concerning the efficacy of yogic practice on female college students during the stressful COVID-19 pandemic situation is available.

METHODS

In a randomized controlled trial (n = 74, age = 21.65 [4.05] y), a study was conducted with a well-conceptualized yogic module for 5 days/week for 3 months (40 min daily in the morning) among yogic volunteers. Pre-post analysis of anthropometric, physiological, and biochemical indices in pandemic-stressed female college students was done for the control and yoga groups.

RESULTS

After 3 months of yogic practice, significant reduction (P < .05) in heart rate (d = 0.64, meandiff = 5.43), systolic blood pressure (d = 0.59, meandiff = 5.32), cortisol (d = 0.59, meandiff = 6.354), and triglycerides (P < .01, d = 0.45, meandiff = 13.95) was observed. After yogic follow-up significant improvement (P < .01) in high-frequency (d = 0.56, meandiff = -7.3), total power (d = 0.46, meandiff = -1150) and time domain parameters of heart rate variability led to ameliorate the stress index. Superoxide dismutase (P < .01, d = 0.78, meandiff = 0.69), catalase (P < .05, d = 0.48, meandiff = -7.37), glutathione (P < .001, d = 0.83, meandiff = -4.15), high-density lipoprotein (P < .05, d = 0.48, meandiff = -11.07), and dopamine (P < .001, d = 0.97, meandiff = -135.4) values along with inflammatory markers (P < .001) significantly improved among yogic volunteers after regular practice.

CONCLUSIONS

Our findings suggest that a 3-month well-conceptualized yogic intervention during COVID-19 may be considered as a prophylactic tool to improve female college students' universal psychophysiological health by ameliorating autonomic functions, cardiometabolic risk factors, and immune metabolisms in an economical and environment-friendly manner.

A prospective study of the impact of COVID-19-related restrictions on activities and mobility upon physical activity, travel behaviour and attitudes

Background and aims

Public health measures adopted to contain the spread of COVID-19 included restrictions on activities and mobility as people were asked to stay at home and schools moved to online learning. This may have increased risk of non-communicable disease by limiting recreational and transport-related physical activity. Building on an existing study, we assessed changes in self-reported and device-measured physical activity and travel behaviour before, during and after the peak of local COVID-19 outbreak and restrictions (March-July 2020). We examined beliefs in effectiveness of strategies to increase active and public transport after restrictions were reduced.

Methods

A longitudinal study of adult infrequent bus users (average ≤ 2 trips per week; n = 70; 67% women) in Hobart, Australia. One-week assessment periods at four separate timepoints (before, during, 0-3 months after, and 3-6 months after the peak restrictions period) involved wearing an accelerometer, daily transport diaries, online surveys and tracking bus smartcard boardings.

Results

Physical activity (especially among older participants), bus use and private motor vehicle use declined significantly during or 0-3 months after the peak restrictions period and returned to pre-restrictions levels by 3-6 months after the peak restrictions period, except bus use which remained significantly lower. Retrospective surveys overstated declines in bus use and active transport and self-reports understated declines in physical activity. Social distancing and improving service efficiency and frequency were seen as effective strategies for increasing bus use after restrictions but belief in effectiveness of distancing decreased over time.

Conclusions

When restrictions on mobility are increased, supportive health promotion measures are needed to prevent declines in physical activity, particularly for older adults. Public transport systems need capacity to implement temporary distancing measures to prevent communicable disease transmission. Providing convenient, flexible, and efficient options for public transport may help to replenish public transport use after restrictions are reduced.

Effect of COVID-19 on Stress and Biomarkers: An Exploratory Cross-Sectional Study

Background Anxiety and stress in COVID-19 lead to continual pro-inflammatory cytokine activity resulting in excessive inflammation. Levels of different bio indices of COVID-19 may predict clinical outcomes and the severity of COVID-19 disease and may correlate with anxiety and stress levels. Objectives To measure the level of anxiety in COVID-19 patients using the coronavirus anxiety scale (CAS) as an assessment of psychological stress. To measure the levels of blood biomarkers and biochemical and hematological markers of inflammation in COVID-19. To record and measure the indices of short-term HRV in COVID-19 patients to assess their physiological and psychological stress levels. To determine the relationship between anxiety scores, levels of laboratory indices (blood biomarkers), and HRV parameters across mild, moderate and severe cases of COVID-19. Material and method A total of 300 COVID-19 patients aged between 18 and 55 years were included. A questionnaire-based CAS was used to assess anxiety levels. Short-term HRV was recorded to measure stress. Blood biomarkers: Biochemical and hemato-cytological markers of inflammation were measured. Statistical analyses were performed using the SPSS software version 20.0. Results Anxiety and stress increased with the severity of COVID-19. A positive correlation was detected between anxiety and serum ferritin, IL-6, MCV, and MCH levels, and a negative correlation between the corona anxiety score and RBC count. The increase in the severity of COVID-19 showed elevated levels of WBC count, neutrophil%, platelet count, neutrophil/lymphocyte ratio, serum ferritin, D-dimer, C-reactive protein, procalcitonin, interleukin-6, and lactate dehydrogenase, and decreased lymphocyte and monocyte percentages. The increase in the severity of COVID-19 decreased lymphocyte, monocyte, and eosinophil counts. Conclusion The Corona Anxiety Scale and heart rate variability can be used as complementary tools to index COVID-19-related anxiety and stress. An association exists between immune dysregulation and heart rate variability, which can be used to predict the inflammatory response and prognosis of COVID-19.

Clinical presentation and management strategies of cardiovascular autonomic dysfunction following a COVID-19 infection - A systematic review

BACKGROUND

Cardiovascular autonomic dysfunction may reportedly occur after a coronavirus-disease-2019 (COVID-19) infection, but the available evidence is scattered. Here we sought to understand the acute and mid-term effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on cardiovascular autonomic function.

METHODS

We performed a systematic PubMed, Embase, Web of Science, medRxiv, and bioRxiv search for cases of cardiovascular autonomic dysfunction during an acute SARS-CoV-2 infection or post-COVID-19 condition. The clinical-demographic characteristics of individuals in the acute versus post-COVID-19 phase were compared.

RESULTS

We screened 6470 titles and abstracts. Fifty-four full-length articles were included in the data synthesis. One-hundred and thirty-four cases were identified: 81 during the acute SARS-CoV-2 infection (24 thereof diagnosed by history) and 53 in the post-COVID-19 phase. Post-COVID-19 cases were younger than those with cardiovascular autonomic disturbances in the acute SARS-CoV-2 phase (42 vs. 51 years old, p = 0.002) and were more frequently women (68% vs. 49%, p = 0.034). Reflex syncope was the most common cardiovascular autonomic disorder in the acute phase (p = 0.008) and postural orthostatic tachycardia syndrome (POTS) the most frequent diagnosis in individuals with post-COVID-19 orthostatic complaints (p < 0.001). Full recovery was more frequent in individuals with acute versus post-COVID-19 onset of cardiovascular autonomic disturbances (43% vs. 15%, p = 0.002).

CONCLUSIONS

There is evidence from the scientific literature about different types of cardiovascular autonomic dysfunction developing during and after COVID-19. More data about the prevalence of autonomic disorders associated with a SARS-CoV-2 infection are needed to quantify its impact on human health.

The impact of pandemic-related social distancing regulations on exercise performance-Objective data and training recommendations to mitigate losses in physical fitness

Introduction

In the context of the COVID-19 pandemic in Germany, governmental restrictions led to the closure of sports facilities for several months. To date, only subjective and fitness-tracking related data on physical activity during the pandemic are available. Using data of a chip-controlled fitness circuit, training data as a measure of physical performance before and after the lockdown during the first wave of the COVID-19 pandemic will show the impact of the training interruption on exercise performance in middle-aged and older adults. The re-training data are analyzed, to extract practical recommendations.

Methods

Objective training data of 17,450 participants [11,097 middle-aged (45-64 yrs), 6,353 older (≥65 yrs)] were exported from chip-controlled milon^® fitness circuit systems before and after the first COVID-19 related lockdown in Germany. The change in the product of training weight (sum of lifting and lowering the training weight) and repetitions on the leg extension resistance exercise device (leg score) between the last three training sessions before the lockdown and the first ten training sessions after individual training resumption as well as the last training session before the second lockdown in October 2020 was analyzed.

Results

Participants who trained with high intensity before the lockdown, experienced deleterious effects of the training interruption (middle-aged group: -218 kg, older group: ~-230.8 kg; p < 0.001 for change in leg score from to post-lockdown) with no age effect. Participants training with a leg score of more than 3,000 kg did not resume their leg score until the second lockdown.

Conclusion

The interruption of training in a fitness circuit with combined resistance and endurance training due to the lockdown affected mainly those participants who trained at high intensity. Apparently, high-intensity training could not be compensated by home-based training or outdoor activities. Concepts for high-intensity resistance training during closure of sports facilities are needed to be prepared for future periods of high incidence rates of infectious diseases, while especially vulnerable people feel uncomfortable to visit sports facilities.

Trial registration

Identifier, DRKS00022433.

Reduced heart rate variability and expressive suppression interact to prospectively predict COVID-19 pandemic-related post-traumatic stress symptoms

The COVID-19 pandemic is a unique period of stress that, in some cases, led to post-traumatic stress symptoms (PTSSs). Emotion regulation strategies are known to modulate the emotional response to stressful events. Expressive suppression (ES) is a maladaptive strategy related to the exacerbation of the physiological stress response. Heart rate variability (HRV), an index of cardiac autonomic balance strictly related to ES, was also shown to predict PTSSs. This was the first study to investigate whether the pre-pandemic ES use and resting-state HRV predicted pandemic-related PTSSs. Before the pandemic, 83 (58 females) university students completed the Emotion Regulation Questionnaire (ERQ), self-report measures of anxiety and depressive symptoms, and a three-minute resting-state electrocardiogram recording. After 12 months, 61 (45 females) participants completed a self-report measure of pandemic-related PTSSs and repeated the self-report psychological measures. Pre-pandemic anxiety symptoms prospectively predicted greater PTSSs. Moreover, a significant interaction between HRV and ES in predicting PTSSs emerged, whereby those who had higher levels of ES and reduced HRV showed higher PTSSs. These findings suggest that an integrated assessment of HRV and ES might be useful for identifying individuals who are more vulnerable to the development of PTSSs during crises.

Dysautonomia in Children with Post-Acute Sequelae of Coronavirus 2019 Disease and/or Vaccination

Long-term health problems such as fatigue, palpitations, syncope, and dizziness are well-known in patients after COVID-19 (post-acute sequelae of coronavirus (PASC)). More recently, comparable problems have been noticed after the SARS-CoV-2 vaccination (post-VAC). The pathophysiology of these problems is not well-understood. Methods: In 38 children and young adults, we tested if these health problems were related to dysautonomia in an active standing test (Group 1: 19 patients after COVID-19; Group 2: 12 patients with a breakthrough infection despite a vaccination; and Group 3: 7 patients after a vaccination without COVID-19). The data were compared with a control group of 47 healthy age-matched patients, as recently published. Results: All patients had a normal left ventricular function as measured by echocardiography. Significantly elevated diastolic blood pressure in all patient groups indicated a regulatory cardiovascular problem. Compared with the healthy control group, the patient groups showed significantly elevated heart rates whilst lying and standing, with significantly higher heart rate increases. The stress index was significantly enhanced in all patient groups whilst lying and standing. Significantly decreased pNN20 values, mostly whilst standing, indicated a lower vagus activity in all patient groups. The respiratory rates were significantly elevated in Groups 1 and 2. Conclusion: The uniform increase in the heart rates and stress indices, together with low pNN20 values, indicated dysautonomia in children with health problems after COVID-19 disease and/or vaccination. A total of 8 patients fulfilled the criteria of postural orthostatic tachycardia syndrome and 9 patients of an inappropriate sinus tachycardia, who were successfully treated with omega-3 fatty acid supplementation and pharmacotherapy.

Longitudinal observations of sympathetic neural activity and hemodynamics during 6 months recovery from SARS-CoV-2 infection

Cross-sectional data indicate that acute SARS-CoV-2 infection increases resting muscle sympathetic nerve activity (MSNA) and alters hemodynamic responses to orthostasis in young adults. However, the longitudinal impact of contracting SARS-CoV-2 on autonomic function remains unclear. The aim of this study was to longitudinally track MSNA, sympathetic transduction to blood pressure (BP), and hemodynamics over 6 months following SARS-CoV-2 infection. Young adults positive with SARS-CoV-2 reported to the laboratory three times over 6 months (V1:41 ± 17, V2:108 ± 21, V3:173 ± 16 days post-infection). MSNA, systolic (SBP) and diastolic (DBP) blood pressure, and heart rate (HR) were measured at rest, during a cold pressor test (CPT), and at 30° head-up tilt (HUT). Basal SBP (p = 0.019) and DBP (p < 0.001) decreased throughout the 6 months, whereas basal MSNA and HR were not different. Basal sympathetic transduction to BP and estimates of baroreflex sensitivity did not change over time. SBP and DBP were lower during CPT (SBP: p = 0.016, DBP: p = 0.007) and HUT at V3 compared with V1 (SBP: p = 0.041, DBP: p = 0.017), with largely no changes in MSNA. There was a trend toward a visit-by-time interaction for burst incidence (p = 0.055) during HUT, wherein at baseline immediately prior to tilting, burst incidence was lower at V3 compared with V1 (p = 0.014), but there were no differences between visits in the 30 HUT position. These results support impairments to cardiovascular health, and potentially autonomic function, which may improve over time. However, the improvements in BP over 6 months recovery from mild SARS-CoV-2 infection are likely not a direct result of changes in sympathetic activity.

Autonomic Dysfunction during Acute SARS-CoV-2 Infection: A Systematic Review

Although autonomic dysfunction (AD) after the recovery from Coronavirus disease 2019 (COVID-19) has been thoroughly described, few data are available regarding the involvement of the autonomic nervous system (ANS) during the acute phase of SARS-CoV-2 infection. The primary aim of this review was to summarize current knowledge regarding the AD occurring during acute COVID-19. Secondarily, we aimed to clarify the prognostic value of ANS involvement and the role of autonomic parameters in predicting SARS-CoV-2 infection. According to the PRISMA guidelines, we performed a systematic review across Scopus and PubMed databases, resulting in 1585 records. The records check and the analysis of included reports’ references allowed us to include 22 articles. The studies were widely heterogeneous for study population, dysautonomia assessment, and COVID-19 severity. Heart rate variability was the tool most frequently chosen to analyze autonomic parameters, followed by automated pupillometry. Most studies found ANS involvement during acute COVID-19, and AD was often related to a worse outcome. Further studies are needed to clarify the role of autonomic parameters in predicting SARS-CoV-2 infection. The evidence emerging from this review suggests that a complex autonomic nervous system imbalance is a prominent feature of acute COVID-19, often leading to a poor prognosis.

Inflammatory reflex disruption in COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified in Wuhan, China, in late 2019 and caused coronavirus disease 2019 (COVID-19), which is still a global pandemic. In most infected people, SARS-CoV-2 can only cause moderate symptoms, while in other patients, it leads to severe illness and eventually death. Although the main clinical manifestation of COVID-19 is often seen in the lungs, this disease affects almost all body organs. The excessive and prolonged release of inflammatory cytokines that may occur in COVID-19 patients, known as cytokine storms, stimulates undesired immune responses and can cause various tissues damage. In the current review article, we focus on the potential advantages of the intrinsic cholinergic anti-inflammatory pathway (CAP) as the efferent arm of inflammatory reflex in COVID-19 management. Considering this endogenous protective mechanism against chronic inflammation, we focused on the effects of SARS-CoV-2 in the destruction of this anti-inflammatory system. Several studies indicated the interaction of SARS-CoV-2 with the alpha7 subtype of the nicotinic acetylcholine receptor as the effector molecule of the inflammatory reflex. On the other hand, neurological manifestations have increasingly been identified as significant extrapulmonary manifestations of COVID-19. The rational connection between these findings and COVID-19 pathogenesis may be an important issue in both our understanding and dealing with this disease. COVID-19 is deeply rooted in our daily life and requires an urgent need for the establishment of effective therapeutic options, and all the possible treatments must be considered for the control of such inflammatory conditions.

Alterations in clinical characteristics of blood donors post COVID-19 recovery

BACKGROUND

Corona Virus Disease-19 (COVID-19), a current worldwide pandemic is a cuase of concern. Risk-adjusted differences in outcomes of the patients are not well characterized. Susceptibility to infection with respect to blood group, blood pressure, pulse rate, hemoglobin, age and BMI were analyzed.

METHODS

Blood donors, of all the ages and gender, who recovered from COVID-19 infection, were selected for the study Samples from Regional laboratory and the Central blood bank of Hafr al Batin, Saudi Arabia were collected. Out of 1508 healthy blood donor 134 had recovered from corona without any preexisting diseases.

RESULTS

Major donors were male (85.1%). 28% donors in age range of 26-35 years. O+(32.8%) were the highest donors. Systolic and diastolic blood pressure and pulse rate elevated significantly of age group 46-55 (p<0.05) and 56-65 (p<0.001). Systolic blood pressure in males (134.13 ± 9.57) was significantly higher (p<0.05) than those of females (129.35 ± 10.61). Donors with Rh+ significantly higher systolic (p<0.05) and pulse rate (p<0.05) as compared to Rh-.

DISCUSSION

O+ donors were highly susceptible. Blood pressure, pulse rate and Hb alter with age. Males exhibit higher variation in systolic blood pressure, with Rh+ factor playing a predominant role. Donors above 45-years of age and a high BMI have significantly elevated blood pressure and pulse. These results are challenging or contradictory from the results of Turkish and Chinese studies where blood group A+ was more predominantly affected by the SARS-CoV-2 with minimum infection rate on females and Rh- donors.

CONCLUSION

Factors like blood group V-2 treatment especially with the age group of 45 years and above.

Safe in my heart: resting heart rate variability longitudinally predicts emotion regulation, worry, and sense of safeness during COVID-19 lockdown

Resting heart rate variability (HRV), a surrogate index of cardiac vagal modulation, is considered a putative biomarker of stress resilience as it reflects the ability to effectively regulate emotions in a changing environment. However, most studies are cross-sectional, precluding longitudinal inferences. The high degree of uncertainty and fear at a global level that characterizes the COVID-19 pandemic offers a unique opportunity to explore the utility of HRV measures as longitudinal predictors of stress resilience. This study examined whether resting measures of HRV prior to the COVID-19 outbreak (i.e. nearly 2 years before; Time 0) could predict emotion regulation strategies and daily affect in healthy adults during the May 2020 lockdown (Time 1). Moreover, we evaluated the association between HRV measures, emotion regulation strategies, subjective perception of COVID-19 risk, and self-reported depressive symptoms at Time 1. Higher resting HRV at Time 0 predicted a stronger engagement in more functional emotion regulation strategies, as well as of higher daily feelings of safeness and reduced daily worry at Time 1. Moreover, depressive symptoms negatively correlated with HRV and positively correlated with the subjective perception of COVID-19 risk at Time 1. Current data support the view that HRV might not only be a marker but also a precursor of resilience under stressful times.

Applying psychophysiological coherence training based on HRV-biofeedback to enhance pilots’ resilience and wellbeing

Introduction. The COVID-19 pandemic not only limited pilots’ proficiency in performing routine tasks, but also increased stress levels and operational risk due to new procedures in flight operations related to safety and health regulations. There is, therefore, an increasing need to improve pilots’ mental and physical health to maintain aviation safety

Research question. (1) Does the practice of psychophysiological coherence using heart rate variability (HRV) biofeedback and the Quick Coherence Technique (QCT) improve pilots’ resilience? (2) What effects does psychophysiological coherence practice have on pilots’ resilience and wellbeing?

Method. Eighteen commercial pilots’ perceived stress and wellness were evaluated subjectively by the Perceived Stress Scale (PSS) and Ardell Wellness Self-Assessment (AWSA). They were taught the QCT for facilitating psychophysiological coherence, and their HRV data reflecting automatic nervous system (ANS) activities were collected as they practiced QCT via Inner Balance HRV sensors.

Results. The QCT training improved pilots’ AWSA scores (t = -3.55, p = .002) and decreased PSS scores (t = 6.37, p < .001). Pilots’ post-training HRV were improved with SDNNs higher than pre-training, t = -4.88, p < .001; normalized low frequency (LF) power increased (t = -10.91, p < .001) and low-frequency to high-frequency (LF/HF) ratios increased (t = -3.92, p = .001). Additionally, pilots’ post-training respiration rates were lower than pre-training, t = -2,45, p = .025.

Discussion. Based on the empirical data analysis, HRV-biofeedback QCT can improve psychophysiological coherence and thereby increase pilots’ resilience and wellbeing. Increased post-training SDNNs, normalized LF power, and LF/HF ratio indicate the improvement of ANS control and balance, and stress management capacity. These findings demonstrate the effectiveness of HRV-biofeedback QCT training in improving psychophysiological coherence, which confers real-time and post-practice benefits of optimal energy utility and self-regulation in challenging situations on flight operations and everyday life.

Conclusion. This research demonstrates significant benefits of a short session of HRV-biofeedback QCT on pilots’ resilience and cognitive process by improving psychophysiological coherence. HRV-biofeedback QCT training can be an effective intervention for aviation authorities and airline operators to develop peer support programs for pilots to increase psychological resilience and wellbeing. This may be particularly beneficial given the various challenges presented to pilots in their preparation for return to normal operations.

Nature in virtual reality improves mood and reduces stress: evidence from young adults and senior citizens

Large populations worldwide have been deprived from nature experiences due to mass quarantines and lockdowns during the COVID-19 pandemic, and face a looming mental health crisis. Virtual reality offers a safe and practical solution to increase nature exposure. This research examined the effects of virtual nature using a within-subject design with young adults (Study 1) and senior citizens (Study 2). Results from the young adult sample showed that walking in a virtual forest reduced negative affect due to enhanced nature connectedness, and reduced stress measured by heart rate. Consistently, the senior citizen sample reported improved positive affect due to enhanced nature connectedness after the virtual nature walk. Our findings unveil the underlying mechanism of how virtual nature may improve psychological well-being and demonstrated how virtual nature can be used as an intervention to promote mental health.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10055-021-00604-4.

Chronotropic Incompetence in Non-Hospitalized Patients with Post-COVID-19 Syndrome

Patients recovering from COVID-19 commonly report persistence of dyspnea, exertional fatigue, and difficulties in carrying out their daily activities. However, the nature of these symptoms is still unknown. The purpose of the study was to identify limiting causes of cardiopulmonary origin for the performance of physical exercise in post-COVID-19 condition that could explain the symptomatic persistence of dyspnea or fatigue-related symptoms. Thirty-two non-hospitalized patients with post-COVID-19 condition (i.e., still presenting a chronic symptomatic phase lasting >90 days since debut of symptoms that lasted for at least 2 months and cannot be explained by an alternative diagnosis) completed a clinical examination including echocardiography, submaximal and maximal cardiorespiratory fitness tests (Ekblom-Bak and Bruce’s protocols), and a battery of validated questionnaires about fatigue and exercise intolerance. Four participants (12.5%) reported an abnormal cardiac response to exercise during the submaximal test, which aroused suspicion of the presence of chronotropic incompetence. All of them were confirmed with a positive diagnosis maximal exercise test after cardiology screening, even with a comprehensive clinical examination, resting ECG, and echocardiogram, without other findings. No statistical differences were found in any physiological variables or questionnaire values, between patients with positive and negative diagnoses. Chronotropic incompetence and other autonomic disorders may appear in patients with mild forms of COVID-19 presentation and may persist in the long term, being responsible for exercise intolerance after resolution of acute infection. Clinicians should be aware that chronotropic incompetence and other autonomic disorders may be a complication of COVID-19 and should consider appropriate diagnostic and therapeutic interventions in these patients, especially when early exercise-related fatigability is reported.

Effect of COVID-19 home confinement on sleep monitorization and cardiac autonomic function in people with multiple sclerosis: A prospective cohort study✰,✰✰

BACKGROUND

Low sleep quality, cardiac autonomic dysfunction and poor quality of life are some of the most prevalent symptoms in people with Multiple Sclerosis (MS). In addition to the progression of the disease, these symptoms are aggravated by physical inactivity. Therefore, home confinement due to COVID-19 pandemic restrictions could further worsen these symptoms. This study aims to analyze the effect of home confinement on objective and subjective sleep quality, cardiac autonomic control based on heart rate variability (HRV), and health-related quality of life in people with MS.

METHODS

Actigraphic and subjective sleep quality (Karolinska Sleep Diary, KSD), HRV (Polar-H7), and quality of life (Multiple Sclerosis Quality of Life-54) were measured before and after 2 months of home confinement in 17 people with MS (7:10 men/women; age: 43.41±10.88 years; body mass index: 24.87±3.31 kg/m²; Expanded Disability Status Scale: 2.85±1.34 a.u.).

RESULTS

Actigraphic sleep quality (sleep efficiency: ES=1.27, p = 0.01, sleep time: ES=0.81, p = 0.01) and subjective sleep quality (sleep quality: ES=-0.34, p = 0.05), sleep comfort: ES=0.60; p = 0.03, ease of falling asleep: ES=0.70; p = 0.01, ease of waking up: ES=0.87, p<0.01, and having enough sleep: ES=0.87, p<0.01) significantly decreased after home confinement. No differences were observed in HRV or quality of life variables (p ≥ 0.13).

CONCLUSIONS

Home confinement has worsened the sleep quality, but not in cardiac autonomic control or quality of life, in people with MS. These data highlight the importance of implementing home physical training programs in this population when situations similar to home confinement occur, thus minimizing the negative effects of physical inactivity and their associated comorbidities.

Clinical characterization of dysautonomia in long COVID-19 patients

Increasing numbers of COVID-19 patients, continue to experience symptoms months after recovering from mild cases of COVID-19. Amongst these symptoms, several are related to neurological manifestations, including fatigue, anosmia, hypogeusia, headaches and hypoxia. However, the involvement of the autonomic nervous system, expressed by a dysautonomia, which can aggregate all these neurological symptoms has not been prominently reported. Here, we hypothesize that dysautonomia, could occur in secondary COVID-19 infection, also referred to as "long COVID" infection. 39 participants were included from December 2020 to January 2021 for assessment by the Department of physical medicine to enhance their physical capabilities: 12 participants with COVID-19 diagnosis and fatigue, 15 participants with COVID-19 diagnosis without fatigue and 12 control participants without COVID-19 diagnosis and without fatigue. Heart rate variability (HRV) during a change in position is commonly measured to diagnose autonomic dysregulation. In this cohort, to reflect HRV, parasympathetic/sympathetic balance was estimated using the NOL index, a multiparameter artificial intelligence-driven index calculated from extracted physiological signals by the PMD-200 pain monitoring system. Repeated-measures mixed-models testing group effect were performed to analyze NOL index changes over time between groups. A significant NOL index dissociation over time between long COVID-19 participants with fatigue and control participants was observed (p = 0.046). A trend towards significant NOL index dissociation over time was observed between long COVID-19 participants without fatigue and control participants (p = 0.109). No difference over time was observed between the two groups of long COVID-19 participants (p = 0.904). Long COVID-19 participants with fatigue may exhibit a dysautonomia characterized by dysregulation of the HRV, that is reflected by the NOL index measurements, compared to control participants. Dysautonomia may explain the persistent symptoms observed in long COVID-19 patients, such as fatigue and hypoxia. Trial registration: The study was approved by the Foch IRB: IRB00012437 (Approval Number: 20-12-02) on December 16, 2020.

Clinical characterization of dysautonomia in long COVID-19 patients

Increasing numbers of COVID-19 patients, continue to experience symptoms months after recovering from mild cases of COVID-19. Amongst these symptoms, several are related to neurological manifestations, including fatigue, anosmia, hypogeusia, headaches and hypoxia. However, the involvement of the autonomic nervous system, expressed by a dysautonomia, which can aggregate all these neurological symptoms has not been prominently reported. Here, we hypothesize that dysautonomia, could occur in secondary COVID-19 infection, also referred to as “long COVID” infection. 39 participants were included from December 2020 to January 2021 for assessment by the Department of physical medicine to enhance their physical capabilities: 12 participants with COVID-19 diagnosis and fatigue, 15 participants with COVID-19 diagnosis without fatigue and 12 control participants without COVID-19 diagnosis and without fatigue. Heart rate variability (HRV) during a change in position is commonly measured to diagnose autonomic dysregulation. In this cohort, to reflect HRV, parasympathetic/sympathetic balance was estimated using the NOL index, a multiparameter artificial intelligence-driven index calculated from extracted physiological signals by the PMD-200 pain monitoring system. Repeated-measures mixed-models testing group effect were performed to analyze NOL index changes over time between groups. A significant NOL index dissociation over time between long COVID-19 participants with fatigue and control participants was observed (p = 0.046). A trend towards significant NOL index dissociation over time was observed between long COVID-19 participants without fatigue and control participants (p = 0.109). No difference over time was observed between the two groups of long COVID-19 participants (p = 0.904). Long COVID-19 participants with fatigue may exhibit a dysautonomia characterized by dysregulation of the HRV, that is reflected by the NOL index measurements, compared to control participants. Dysautonomia may explain the persistent symptoms observed in long COVID-19 patients, such as fatigue and hypoxia.

Trial registration: The study was approved by the Foch IRB: IRB00012437 (Approval Number: 20-12-02) on December 16, 2020.

Effects of a Home-Based Lifestyle Intervention Program on Cardiometabolic Health in Breast Cancer Survivors during the COVID-19 Lockdown

This study aimed to evaluate the cardiometabolic effects of a home-based lifestyle intervention (LI) in breast cancer survivors (BCSs) during the COVID-19 lockdown. In total, 30 BCSs (women; stages 0-II; non-metastatic; aged 53.5 ± 7.6 years; non-physically active; normal left ventricular systolic function) with a risk factor for recurrence underwent a 3-month LI based on nutrition and exercise. Anthropometrics, Mediterranean diet adherence, physical activity level (PAL), cardiorespiratory fitness (VO2max), echocardiographic parameters, heart rate variability (average standard deviation of NN intervals (ASDNN/5 min) and 24 h very- (24 hVLF) and low-frequency (24 hLF)), and metabolic, endocrine, and inflammatory serum biomarkers (glycemia, insulin resistance, progesterone, testosterone, and high-sensitivity C-reactive protein (hs-CRP)) were evaluated before (T0) and after (T1) the LI. After the LI, there were improvements in: body mass index (kg/m2: T0 = 26.0 ± 5.0, T1 = 25.5 ± 4.7; p = 0.035); diet (Mediet score: T0 = 6.9 ± 2.3, T1 = 8.8 ± 2.2; p < 0.001); PAL (MET-min/week: T0 = 647 ± 547, T1 = 1043 ± 564; p < 0.001); VO2max (mL·min-1·kg-1: T0 = 30.5 ± 5.8, T1 = 33.4 ± 6.8; p < 0.001); signs of diastolic dysfunction (participants: T0 = 15, T1 = 10; p = 0.007); AS-DNN/5 min (ms: T0 = 50.6 ± 14.4, T1 = 55.3 ± 16.7; p = 0.032); 24 hLF (ms2: T0 = 589 ± 391, T1 = 732 ± 542; p = 0.014); glycemia (mg/dL: T0 = 100.8 ± 11.4, T1 = 91.7 ± 11.0; p < 0.001); insulin resistance (HOMA-IR score: T0 = 2.07 ± 1.54, T1 = 1.53 ± 1.11; p = 0.005); testosterone (ng/mL: T0 = 0.34 ± 0.27, T1 = 0.24 ± 0.20; p = 0.003); hs-CRP (mg/L: T0 = 2.18 ± 2.14, T1 = 1.75 ± 1.74; p = 0.027). The other parameters did not change. Despite the home-confinement, LI based on exercise and nutrition improved cardiometabolic health in BCSs.

Effects of COVID-19 Lockdown and a Subsequent Retraining Period on Elite Athletes' Workload, Performance, and Autonomic Responses: A Case Series

PURPOSE

To describe the effects of COVID-19 lockdown and a subsequent retraining on the training workloads, autonomic responses, and performance of a group of elite athletes.

METHODS

The training workloads and heart rate variability (assessed through the log-transformed root mean square of successive R-R intervals) of 7 elite badminton players were registered daily during 4 weeks of normal training (baseline), 7 to 10 weeks of lockdown, and 6 to 8 weeks of retraining. Physical performance was assessed at baseline and after each phase by means of a countermovement jump and the estimated squat 1-repetition maximum.

RESULTS

A reduction in training workloads was observed in all participants during the lockdown (-63.7%), which was accompanied by a reduced heart rate variability in all but one participant (-2.0%). A significant reduction was also observed for countermovement jump (-6.5%) and 1-repetition maximum performance (-11.5%), which decreased in all but one participant after the lockdown. However, after the retraining phase, all measures returned to similar values to those found at baseline. At the individual level, there were divergent responses, as exemplified by one athlete who attenuated the reduction in training workloads and increased her performance during the lockdown and another one who markedly reduced his workload and performance, and got injured during the retraining phase.

CONCLUSIONS

Although there seems to be a large interindividual variability, COVID-19 lockdown is likely to impose negative consequences on elite athletes, but these detrimental effects might be avoided by attenuating reductions in training workloads and seem to be overall recovered after 6 to 8 weeks of retraining.

COVID-19-Lockdown in Wuhan und die Variabilität der Herzrate — Ein Kurzbericht zu einer Pilotstudie

Frauen haben offensichtlich eine bessere Lockdown-Bewältigungsstrategie im Hinblick auf den allgemeinen Gesundheitszustand als Männer. Eine transkontinentale Pilotstudie an 50 Personen zur Herzratenvariabilität in Wuhan liefert erste Trendhinweise zu dieser Thematik.