Caffeine increases performance and leads to a cardioprotective effect during intense exercise in cyclists

The present study was designed to investigate the effects of different caffeine dietary strategies to compare the impact on athletic performance and cardiac autonomic response. The order of the supplementation was randomly assigned: placebo(4-day)-placebo(acute)/PP, placebo(4-day)-caffeine(acute)/PC and caffeine(4-day)-caffeine(acute)/CC. Fourteen male recreationally-trained cyclists ingested capsules containing either placebo or caffeine (6 mg kg−1) for 4 days. On day 5 (acute), capsules containing placebo or caffeine (6 mg kg−1) were ingested 60 min before completing a 16 km time-trial (simulated cycling). CC and PC showed improvements in time (CC vs PP, Δ − 39.3 s and PC vs PP, Δ − 43.4 s; P = 0.00; ƞ2 = 0.33) and in output power (CC vs PP, Δ 5.55 w and PC vs PP, Δ 6.17 w; P = 0.00; ƞ2 = 0.30). At the final of the time-trial, CC and PC exhibited greater parasympathetic modulation (vagal tone) when compared to the PP condition (P < 0.00; ƞ2 = 0.92). Our study provided evidence that acute caffeine intake (6 mg∙kg−1) increased performance (time-trial) and demonstrated a relevant cardioprotective effect, through increased vagal tone.

Neural basis for anxiety and anxiety-related physiological responses during simulated driving: An fMRI study

While the exteroceptive and interoceptive prediction of a negative event increases a person's anxiety in daily life situations, the relationship between the brain mechanism of anxiety and anxiety-related autonomic response have not been fully understood. In this fMRI study, we examined the neural basis of anxiety and anxiety-related autonomic responses in a daily driving situation. Participants viewed a driving video clip in the first-person perspective. In the middle of the video clip, participants were presented with a cue to indicate whether a subsequent crash could occur (attention condition) or not (safe condition). Compared with the safe condition, there were more activities in the anterior insula, bed nucleus of the stria terminalis, thalamus, and periaqueductal gray, and higher sympathetic nerve responses, such as pupil dilation and peripheral arterial stiffness in the attention condition. We also observed autonomic response-related functional connectivity in the visual cortex, cerebellum, brainstem, and MCC/PCC with the right anterior insula and its adjacent regions as seed regions. Thus, the right anterior insula and adjacent regions, collaborating with the other related regions, could play a fundamental role in eliciting anxiety based on the prediction of negative events by mediating anxiety-related autonomic responses according to interoceptive information.

Autonomic response of gradient exercise testing protocol in normotensive, overweight, and pre-hypertensive individuals: a prospective, observational, and analytical study

Background Coronary artery disease (CAD) is increasing day by day in young Indian population with increase in risk factors such as obesity, hypertension etc. Although in early age, these risk factors are clinically asymptomatic but physiologically they are symptomatic. These symptoms can be best assessed by assessing the response of autonomic nervous system Therefore the purpose of this study was to compare the autonomic response of gradient exercise testing protocol in normotensive, overweight, and pre-hypertensive subjects in the form of chronotropic response to exercise, inotropic reponse, heart rate recovery, blood pressure recovery, BRPE, and heart rate variability so that the physiological abnormalities can be corrected. Results There were significant differences (p < 0.05) found in gradient exercise testing protocol in diastolic blood pressure in normotensive, in heart rate variability in overweight and in both systolic as well as diastolic blood pressure in pre-hypertensive subjects. Conclusion Gradient exercise testing protocol can be best utilized as a clinical tool in normotensive, overweight, and pre-hypertensive subjects for the assessment of autonomic nervous system which provides diagnostic and prognostic information regarding cardiovascular disease or abnormalities.

The Rationale for the Automation of a New Diagnostic Thermography Protocol to Confirm a Chronic-Low-Back-Pain Subtype Related to Nociplastic Pain

Gluteal syndrome (GS), a new low-back-pain subtype mimicking sciatica, has been included in the 11th Revision of the International Classification of Diseases (ICD-11). Low back pain is a symptom, not a disease, and the main problem associated with it is pain complexity. A plausible pain generator of gluteal syndrome is the central sensitization process and the therapeutic target area, which are trigger points located within the gluteal muscles. It has been hypothesized that dysregulated immune and autonomic nervous systems (ANS) are involved in central sensitization development. Changes in ANS regulation, mainly through the sympathetic branch, provoke nociceptor activation indirectly by a vasoconstriction–vasodilatation imbalance, or directly by sympathetic–nociceptor activation resulting in widespread pain, hyperalgesia, and allodynia. The minimally invasive procedure (MIP) uses thermography to confirm a completely new biological phenomenon, which suggests a pathological autonomic response to noxious stimuli and can possibly become an objective marker of some nociplastic pain subtypes related to trigger points. This review provides the biological and technical rationale for the automation of the MIP—a possible future diagnostic tool for an objective gluteal syndrome confirmation.

Acute change in parasympathetic cardiac innervation after pulmonary vein isolation by pulse-field and radiofrequency energy

Background In patients with atrial fibrillation (AF), pulmonary vein isolation (PVI) by radiofrequency (RF) energy is associated with a significant change of cardiac autonomic regulations due to collateral ganglionic plexi ablation. Pulse-field (PF) ablation energy presumably spares neural tissue. Purpose We compared the effect of PVI by PF and RF energy on cardiac autonomic function. Methods A study enrolled 23 patients who underwent PVI in general anaesthesia. In 12 patients, a novel lattice-tip catheter and PF energy were used for ablation while 11 patients were ablated using a conventional irrigated-tip catheter and RF energy. The response of the sinus node (SAN) and atrioventricular node (AVN) to extracardiac high-frequency vagal stimulation (ECVS) was tested before and after PVI (via right internal jugular vein; stimulation frequency of 50 Hz; pulse width of 0.05 ms; output of 1 V/kg (&lt;70V); train duration of 5 s). Results At baseline, physiological massive response to ECVS (sinus arrest and/or AV block) was demonstrated in the majority of patients. After PVI, complete loss of autonomic response of the SAN in 11/11 (100%) and 3/12 (25%) patients (p=0.003), and the AVN in 9/11 (82%) and 3/12 (25%) patients (p=0.01) was observed in RF and PF groups, respectively. The figure shows the maximum duration of the pause in sinus rhythm (maximum P-P interval) and AVN block (maximum R-R interval during atrial pacing) induced by ECVS after PVI. Conclusion Cardiac vagal response is preserved in a considerable proportion of AF patients after PF ablation which is in contrast with a significantly stronger effect of RF energy. This may influence the clinical outcome of AF ablation procedures. FUNDunding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Institute for Clinical and Experimental Medicine, Prague

Caffeine Increases Performance and Leads to a Cardioprotective Effect During Intense Exercise in Cyclists: a Randomized, Double-blind, Crossover, Placebo-controlled Study

The present study was designed to investigate the effects of different caffeine dietary strategies to compare the impact on athletic performance and cardiac autonomic response. The order of the supplementation was randomly assigned: placebo(4-day)-placebo(acute)/PP, placebo(4-day)-caffeine(acute)/PC and caffeine(4-day)-caffeine(acute)/CC. Fourteen male recreationally-trained cyclists ingested capsules containing either placebo or caffeine (6 mg∙kg − 1) for 4 days. On day 5 (acute), capsules containing placebo or caffeine (6 mg∙kg − 1) were ingested 60 min before completing a 16km time-trial. CC and PC showed improvements in time (CC vs PP, Δ -39.3 s and PC vs PP, Δ -43.4 s; p = 0.00; ƞ2=0.33) and in output power (CC vs PP, Δ 5.55 w and PC vs PP, Δ 6.17 w; p = 0.00; ƞ2=0.30). At the final of the time-trial, CC and PC exhibited greater parasympathetic modulation (vagal tone) when compared to the PP condition (p < 0.00; ƞ2=0.92). Our study provided evidence that acute caffeine intake (6 mg∙kg − 1) increased performance and demonstrated a relevant cardioprotective effect, through increased vagal tone.