The effect of cardiorespiratory fitness and habitual physical activity on cardiovascular responses to 2 h of uninterrupted sitting

Prolonged uninterrupted sitting of >3 h has been shown to acutely cause central and peripheral cardiovascular dysfunction. However, individuals rarely sit uninterrupted for >2 h, and the cardiovascular response to this time is currently unknown. In addition, while increased cardiorespiratory fitness (CRF) and habitual physical activity (HPA) are independently associated with improvements in central and peripheral cardiovascular function, it remains unclear whether they influence the response to uninterrupted sitting. This study sought to 1) determine whether 2 h of uninterrupted sitting acutely impairs carotid-femoral pulse wave velocity (cfPWV), femoral ankle PWV (faPWV), and central and peripheral blood pressure and 2) investigate the associations between CRF and HPA versus PWV changes during uninterrupted sitting. Following 2 h of uninterrupted sitting, faPWV significantly increased [mean difference (MD) = 0.26 m·s-1, standard error (SE) = 0.10, P = 0.013] as did diastolic blood pressure (MD = 2.83 mmHg, SE = 1.08, P = 0.014), however, cfPWV did not significantly change. Although our study shows 2 h of uninterrupted sitting significantly impairs faPWV, neither CRF (r = 0.105, P = 0.595) nor HPA (r = -0.228, P = 0.253) was associated with the increases.NEW & NOTEWORTHY We demonstrate that neither cardiorespiratory fitness nor habitual physical activity influence central and peripheral cardiovascular responses to a 2-h bout of uninterrupted sitting in healthy young adults.

Effect of Smartphone Use on Sleep in Undergraduate Medical Students: A Cross-Sectional Study

Smartphone use, particularly at night, has been shown to provoke various circadian sleep-wake rhythm disorders such as insomnia and excessive daytime tiredness. This relationship has been mainly scrutinized among patient groups with higher rates of smartphone usage, particularly adolescents and children. However, it remains obscure how smartphone usage impacts sleep parameters in adults, especially undergraduate college students. This study sought to (1) investigate the association between smartphone use (actual screen time) and four sleep parameters: Pittsburgh sleep quality score (PSQI), self-reported screen time, bedtime, and rise time; (2) compare the seven PSQI components between good and poor sleep quality subjects. In total, 264 undergraduate medical students (aged 17 to 25 years) were recruited from the Government Doon Medical College, Dehradun, India. All participants completed a sleep questionnaire, which was electronically shared via a WhatsApp invitation link. Hierarchical and multinomial regression analyses were performed in relation to (1) and (2). The average PSQI score was 5.03 ± 0.86, with approximately one in two respondents (48.3%) having a poor sleep index. Smartphone use significantly predicted respondents' PSQI score (β = 0.142, p = 0.040, R2 = 0.027), perceived screen time (β = 0.113, p = 0.043, R2 = 343), bedtime (β = 0.106, p = 0.042, R2 = 045), and rise time (β = 0.174, p = 0.015, R2 = 0.028). When comparing poor-quality sleep (PSQI ≥ 5) to good-quality sleep (PSQI < 5), with good-quality sleep as the reference, except sleep efficiency and sleep medications (p > 0.05), five PSQI components declined significantly: subjective sleep quality (β = -0.096, p < 0.001); sleep latency (β = -0.034, p < 0.001); sleep duration (β = -0.038, p < 0.001); sleep disturbances (β = 1.234, p < 0.001); and sleep dysfunction (β = -0.077, p < 0.001). Consequently, public health policymakers should take this evidence into account when developing guidelines around smartphone use-i.e., the when, where, and how much smartphone use-to promote improved sleep behaviour and reduce the rate of sleep-wake rhythm disorders.

The age of computational cardiology and future of long-term ablation target prediction for ventricular tachycardia

Ventricular arrhythmias, particularly ventricular tachycardia, are ubiquitously linked to 300,000 deaths annually. However, the current interventional procedure-the cardiac ablation-predict only short-term responses to treatment as the heart constantly remodels itself post-arrhythmia. To assist in the design of computational methods which focuses on long-term arrhythmia prediction, this review postulates three interdependent prospectives. The main objective is to propose computational methods for predicting long-term heart response to interventions in ventricular tachycardia Following a general discussion on the importance of devising simulations predicting long-term heart response to interventions, each of the following is discussed: (i) application of "metabolic sink theory" to elucidate the "re-entry" mechanism of ventricular tachycardia; (ii) application of "growth laws" to explain "mechanical load" translation in ventricular tachycardia; (iii) derivation of partial differential equations (PDE) to establish a pipeline to predict long-term clinical outcomes in ventricular tachycardia.

Evaluation of strategies against vaccine hesitancy in the COVID-19 and Indian context-A systematic review

The world has been severely affected by the COVID-19 pandemic in terms of loss of lives, health, and its socioeconomic consequences; however, the true magnitude and extent of the damage from COVID-19 is still elusive till date. With the advent of many efficacious vaccines, one of the most effective ways to get to grips with the pandemic is mass vaccination. However, due to vaccine hesitancy (VH), it remains a colossal challenge globally thereby causing serious threat to the pandemic response efforts. This review intends to identify evaluated interventions and evidence to support recommendation of specific strategies to address VH from an Indian context. A systematic review was conducted to synthesize relevant literature around the evaluation of strategies to tackle VH for effectiveness or impact in India. Electronic databases were searched using specific keywords and predefined inclusion-exclusion criteria. A total of 133 articles were screened, 15 were assessed for eligibility, and two were included in the final review. There is a paucity of research on evaluation of vaccine hesitancy interventions in India. Evidence is not strong enough to recommend one specific strategy or intervention. Together, a permutation of multicomponent and tailored interventions has been found most effective in repressingVH in India.

Precision Medicine and the future of Cardiovascular Diseases: A Clinically Oriented Comprehensive Review

Cardiac diseases form the lion's share of the global disease burden, owing to the paradigm shift to non-infectious diseases from infectious ones. The prevalence of CVDs has nearly doubled, increasing from 271 million in 1990 to 523 million in 2019. Additionally, the global trend for the years lived with disability has doubled, increasing from 17.7 million to 34.4 million over the same period. The advent of precision medicine in cardiology has ignited new possibilities for individually personalized, integrative, and patient-centric approaches to disease prevention and treatment, incorporating the standard clinical data with advanced "omics". These data help with the phenotypically adjudicated individualization of treatment. The major objective of this review was to compile the evolving clinically relevant tools of precision medicine that can help with the evidence-based precise individualized management of cardiac diseases with the highest DALY. The field of cardiology is evolving to provide targeted therapy, which is crafted as per the "omics", involving genomics, transcriptomics, epigenomics, proteomics, metabolomics, and microbiomics, for deep phenotyping. Research for individualizing therapy in heart diseases with the highest DALY has helped identify novel genes, biomarkers, proteins, and technologies to aid early diagnosis and treatment. Precision medicine has helped in targeted management, allowing early diagnosis, timely precise intervention, and exposure to minimal side effects. Despite these great impacts, overcoming the barriers to implementing precision medicine requires addressing the economic, cultural, technical, and socio-political issues. Precision medicine is proposed to be the future of cardiovascular medicine and holds the potential for a more efficient and personalized approach to the management of cardiovascular diseases, contrary to the standardized blanket approach.

Localized activity attenuates the combined impact of a high fat meal and prolonged sitting on arterial stiffness: A randomized, controlled cross-over trial

Exposure to acute prolonged sitting and consumption of a high fat (HF) meal have been shown to independently and additively impair central and peripheral cardiovascular function. This study sought to determine whether localized activity, namely leg fidgeting, offers a protective effect to these deleterious effects. Using a randomized crossover design with three trials, 18 healthy males sat uninterrupted for 180 min following the consumption of a low fat (LF, trial 1) or HF meal (trial 2). The third trial consisted of a HF meal but sitting was interrupted with 1 min of leg fidgeting (isolated bilateral plantar flexion) consisting of -250 taps per min every 5 min for the 180 min duration. Carotid-femoral pulse wave velocity (cfPWV), aortic-femoral stiffness gradient (af-SG), superficial femoral blood flow, shear-rate and PWV_β, triglyceride concentrations and lower-limb venous pooling (HHb) were assessed pre and post sitting in all trials. General linear mixed model found that following the uninterrupted HF trial, there was a significant worsening of cfPWV (mean difference (MD) = 0.57 mˑs^-1; d = 1.04) and the af-SG (MD = 0.14, d = 0.50), and femoral artery blood flow (MD = 18 mlˑmin^-1; d = 0.48) and shear rate (MD = 15 S¹; d = 0.67) decreased. However, leg fidgeting was enough to prevent the combined deleterious effects of prolonged sitting following a HF meal. As there were no significant changes in the LF trial, the HF meal maybe the predominant driver when uninterrupted sitting is combined with a HF meal.

Competency-based medical education (CBME) curriculum and its effect on prevalence of anxiety, depression and stress amongst medical undergraduates

BACKGROUND

A growing body of literature now identifies higher levels of anxiety, depression, and stress among medical students as a distinct mental health domain. The competency-based medical education (CBME) curriculum was introduced to revamp the existing curriculum with an aim to garner constructive impact on the mental health of undergraduate medical students. As such, we sought to draw comparisons between the mental health of medical students, studying the old (2018 batch) and the new (2019 batch) medical education systems in India.

MATERIALS AND METHODS

We designed a survey that contained structured questions pertained to anxiety (HAM-A, GAD-7), depression (HAM-D, BDI), and stress (PSS) amongst medical undergraduate students of 2018 and 2019 batches at the Government Doon Medical College (GDMC), Dehradun, India.

RESULTS

Contrasting the 2018 and 2019 batches, the introduction of CBME resulted in a significant two-fold decrease in moderate anxiety, as exhibited by both HAM-A (6.0 vs 3.0, P = 0.016) and GAD-7 (3.5 vs 1.0, P = 0.037) scales, although no significant change in mild and severe anxiety, and overall depression (BDI: P = 0.05, HAM-D: P = 0.05) or stress (PSS: P = 0.86) was found.

CONCLUSION

The CBME system has made a significant impact on the mental health of undergraduate medical students for anxiety, albeit its effect on depression and stress remains equivocal. Future studies are warranted to compare the effect of CBME in other undergraduate and postgraduate courses across the country to help predict the psychological impact of the newfangled CBME education system.

Assessment of Anthropometric Indices, Salt Intake and Physical Activity in the Aetiology of Prehypertension

INTRODUCTION

Globally, prehypertension is responsible for approximately 62% of cardiovascular and 49% of ischemic heart disease (IHD) episodes. Current data from the Indian subcontinent suggests that prevalence of prehypertension was 47% amongst young urban residents. Considering its serious prognosis, the current study was undertaken to assess risk factors such as for cardiovascular diseases in prehypertensives adult males in Uttarakhand region.

MATERIALS AND METHODS

This cross-sectional analytical study was conducted in the Department of Physiology, HIMS, Dehradun, over a period of 12 months. Volunteers (20-40 years) were divided into two groups; Group I (Controls): normotensives and Group II (Cases): prehypertensives based on JNC VII classification.

RESULTS

Exercise capacity, determined by peak VO2 consumption was significantly lower in prehypertensive group than the normotensive group (p<0.001). Daily salt intake of pre-hypertensives was significantly greater than the normotensive subjects (p<0.001). Multiple Linear Regression analysis revealed that average baseline SBP increases by 0.34 mmHg for every 1 kg increase in weight and average baseline DBP increases by 0.25 mmHg for every 1 year increase in age.

CONCLUSION

Exercise capacity was found decreased in pre-hypertensives and they have high daily salt intake. Also, weight and age emerged as independent risk factors for SBP and DBP respectively.

Blood pressure reduction following accumulated physical activity in prehypertensive

Context:

Accumulated moderate physical activity (PA) for 30 min in a day is the only recommended treatment of prehypertension.

Objective:

We investigated autonomic modulation as a possible mechanism for the decrease in blood pressure (BP) during the rest periods in each 10 min session of PA.

Design, Setting, and Participants:

We conducted a single-blind randomized multi-arm control trial on 40 prehypertensive (pre-HT) young male adults.

Methods:

Participants were randomly divided by using random number table into four groups. Control (no intervention); Group 1 (walking at 50% of predicted VO₂ peak); Group 2 (walking at 60% of predicted VO₂ peak); Group 3 (walking at 70% of predicted VO₂ peak). BP, heart rate variability (HRV), and heart rate recovery 1 min (HRR 1 min) were measured at baseline and during the rest period after each session of 10 min over 30 min of accumulated physical activity (PAcumm).

Results:

Significant diastolic BP (DBP) reduction (P < 0.001) was observed during the rest period after each session of PAcumm in intervention groups. An average reduction in DBP was more in pre-HT undertaking PAcumm at 70% of predicted VO₂ Peak. Decrease in the mean value of low-frequency (LF) and LF/high-frequency ratio was observed following PAcumm in all intervention groups irrespective of the intensity of PA. No significant association of reduction of BP with HRV and HRR 1 s was observed.

Conclusion:

Reduction in BP was observed during the rest period after each 10 min session of PAcumm irrespective of the intensity of PA. Autonomic modulation does not seem to be the possible mechanism for the reduction in BP during the sessions.

Study of Electrophysiological Changes in Sensory Nerves Among Diabetic Smokers

INTRODUCTION

Neuropathy is one of the most troublesome complication affecting individuals with diabetes. The resultant loss of function in peripheral nerves causes loss of protective sensations and impairs patient's ability to perceive incipient or even apparent ulcerations in the feet.

AIM

This study was undertaken to test the hypothesis of alteration in electrophysiological parameters of nerve before actual manifestations of neuropathy in type 2 diabetic patients and to analyse the effect of smoking on Sensory Nerve Conduction Velocity (SNCV) of diabetic subjects.

MATERIALS AND METHODS

One hundred and twenty diagnosed diabetics were taken as cases while 30 healthy non diabetics were taken as control. Case group was divided into diabetic non-smoker and diabetic smoker. Diabetic smoker were further subdivided into light smoker, moderate smoker and heavy smoker according to smoking index. After detailed history and physical examination SNCV of median and ulnar nerve in upper limb and sural nerve in lower limb was performed.

RESULTS

On comparison of SNCV of median and ulnar nerve of upper limb and sural nerve of lower limb between control and diabetic non-smoker only sural nerve of diabetic non smoker showed significant bilateral decrease. There was significant bilateral decrease in SNCV of median and ulnar nerve of diabetic heavy smoker when compared to control and diabetic non smoker. Similarly, SNCV of sural nerve of diabetic heavy smoker was significantly decreased when compared with control, diabetic non-smoker, diabetic light and moderate smoker. A negative and statistically significant correlation was found between SNCV and smoking index.

CONCLUSION

Present study indicates that nerves of lower limbs are more susceptible to diabetic assault as compared to upper limb suggesting that long nerves are commonly affected. Also, apart from duration and severity of diabetes, smoking itself is an independent factor for diabetic neuropathy.

Autonomic Function Tests in Prehypertensive Young Adult Males of Uttarakhand Region

Pre-hypertensives are at increased risk for rise in blood pressure and cardio vascular morbidities. Autonomic dysfunction is both a cause and effect of high blood pressure. Considering its serious prognosis the current study was undertaken with an aim to assess autonomic functions in pre-hypertensive young adult males. Male volunteers of 20-40 years were divided into normotensives (n=44) and clinically healthy pre-hypertensives (n=44). They were subjected to anthropometric measurements, Heart Rate variability (HRV) analysis along with Standard Isometric Handgrip Test (HGT) and Sinus arrhythmia test. Analysis showed a significant increase in sympathetic activity among prehypertensives characterized by lower rise in DBP (mmHg) in response to HGT: [11.27±3.76 mmHg vs 23.95±6.29 mmHg, (p<0.05)]. Parasympathetic activity was significantly decreased among prehypertensives (HFnu: 30.02±14.43 vs 41.62±14.91, p<0.05); E/I ratio: 1.20±0.10 vs 1.32±0.10, p<0.05). Sympathovagal balance showed prominent sympathetic activity (2.85±1.78 vs 1.75±0.98; (p<0.01) among prehypertensives. Salt intake among prehypertensives was significantly higher than normotensives (21.2±1.2 gm/day vs 9.0±0.5 gm/day: P<0.001). Conclusion: Autonomic dysfunction is evident in prehypertensives with an enhanced sympathetic activity, decreased parasympathetic activity and an altered sympathovagal balance in prehypertensives, salt intake was found on a higher side. Thus lifestyle changes in the form of balanced diet and moderate exercise may be advised to attenuate the risk progression of prehypertension to hypertension.

Regional transport of TNF-alpha across the blood-brain barrier in young ICR and young and aged SAMP8 mice

The blood-brain barrier (BBB) controls the exchange of regulatory substances, including tumor necrosis factor-alpha (TNF), between the brain and the blood. Transport across the BBB of some regulatory substances is altered with aging. Here, we measured the blood to brain unidirectional influx rate (Ki) for whole brain and 10 brain regions for radioactively labeled TNF in three groups of mice: young (2 mo old) ICR (the standard outbred albino laboratory mouse also termed CD-1), young SAMP8 (a strain which develops impaired learning and memory with aging that correlates with an age-related increase in brain levels of amyloid beta protein), and aged (17 mo) SAMP8 mice. In ICR mice, the hypothalamus had the fastest (1.73 microl/g-min) and the parietal cortex the slowest (0.189 microl/g-min) rates of uptake, a regional difference of about 9 fold. No differences in transport into whole brain or brain regions occurred between the ICR and young SAMP8, showing a lack of differences between strains. Transport was higher for the occipital cortex, midbrain, and striatum in aged SAMP8 mice. These results show blood-borne TNF enters some regions of the brain much more readily than others and TNF transport is increased into some brain regions of the SAMP8 mice at an age when learning and memory are impaired.

Regional variations in the transport of interleukin-1alpha across the blood-brain barrier in ICR and aging SAMP8 mice

OBJECTIVES

The blood-brain barrier (BBB) transports blood-borne interleukin-1alpha (IL-1) into the brain by a saturable process. Here, we determined whether all regions of the brain could transport IL-1 and whether transport differed between ICR and SAMP8 mice, a strain which overexpresses amyloid beta protein (Abeta) with aging.

METHODS

We used multiple-time regression analysis to measure the unidirectional influx rate (transport rate) of radioactively labeled IL-1 for 10 brain regions in young (2 months old) ICR mice and in young and aged (17 months old) SAMP8 mice. We also used radioactively labeled sucrose and albumin to determine whether the BBB was disrupted in aged SAMP8 mice.

RESULTS

In young ICR mice, eight of the 10 brain regions transported IL-1, with the pons-medulla having the fastest transport rate (0.584 +/- 0.163 microl/g x min), but no statistically significant differences occurred among regions. In SAMP8 mice, only four regions transported IL-1. In young SAMP8 mice, the pons-medulla transported IL-1 faster than any other region (0.642 +/- 0.197 microl/g x min), a rate that was significantly different (p < 0.01) from each of the other regions. Aged SAMP8 mice had a similar regional transport pattern to young SAMP8 mice, but there were no statistically significant differences among the four transporting regions. Sucrose and albumin spaces were not increased in aged SAMP8 mice, demonstrating an intact BBB.

CONCLUSIONS

The smaller number of regions transporting IL-1 in SAMP8 mice as compared to ICR mice demonstrates a genetic influence on transport which could alter the ability of blood-borne IL-1 to directly affect brain functions. No evidence of BBB disruption was found in the aged SAMP8 mice from this colony.