Blood pressure changes highlight gender differences in emotional reactivity to arousing pictures

The current study was aimed at investigating the effects of gender on the magnitude and patterning of blood pressure responses to specific pleasant and unpleasant, arousing visual stimuli. Systolic and diastolic blood pressure (SBP and DBP), as well as heart rate (HR) and skin conductance (SCR) responses were investigated during picture viewing in 21 female and 25 male students. The pattern of SCR and HR reactivity across emotional categories was found to be similar for men and women. Gender was found to be an effective moderator of BP responses specifically to sexual stimulus content, which prompted greater reactivity in men than in women. These findings extend prior research on gender differences in autonomic responding to emotional visual stimuli and suggest that BP changes might reflect sexual peripheral arousal more than other autonomic measures.     

Comparison of postnatal development of heart rate responses to trigeminal stimulation in sleeping preterm and term infants

Autonomic dysfunction has been regarded as a possible cause of the sudden infant death syndrome (SIDS) and it has been suggested that preterm infants, who are at a greater risk of SIDS than term infants, may have immature autonomic control. Our aim was to compare the maturation of cardiac autonomic control during sleep in preterm and term infants by examining heart rate responses to arousing and non-arousing trigeminal stimuli. Preterm infants (n = 15) and term infants (n = 24) were studied longitudinally with daytime polysomnography. Air-jet stimulation of the nares was delivered in both active sleep (AS) and quiet sleep (QS), and heart rate (HR) changes recorded for both arousal and non-arousal responses. Changes in HR (DeltaHR%) were calculated as the relative differences between baseline HR (BHR) and either MaxHR (arousal) or MinHR (non-arousal). Comparisons of HR changes between sleep states and postnatal ages were made with two-way anova for repeated measures and between groups with two-way anova. The increase in HR (DeltaHR%) was greater in term than preterm infants (P < 0.05), but only at 2-3 weeks corrected postnatal age (CPA). In preterm infants, there were no differences in BHR between sleep states, whereas in term infants, BHR was higher in AS than in QS at 2-3 weeks and 2-3 months of age. The smaller DeltaHR% to arousing stimuli in preterm infants compared with term infants at 2-3 weeks suggests that cardiac sympathetic activity in preterm infants may be lower than in term infants. This mechanism may account for the increased risk for SIDS of preterm infants.     

帕金森病患者的交感神经皮肤反应研究

目的:研究帕金森病(PD)患者的自主神经功能情况。方法:对40例PD患者和38例健康者分别进行了交感神经皮肤反应(SSR)测定,并将结果加以比较。结果:PD组SSR测定异常率为 75％(30／40),SSR波潜伏期明显延长,波幅降低,与对照组相比差异有显著意义(P<0．01)。结论:PD 患者存在一定的自主神经功能损害,SSR可作为判断PD患者的自主神经功能的参考指标。     

Lack of a relationship between the pupillary light reflex response and state/trait anxiety in remitted patients with panic disorder

OBJECTIVE: Recently, some studies have indicated that pupillary function only correlates with state/trait anxiety in healthy subjects. In the present study, we examined whether or not there were relationships between the PLR functions and state/trait anxiety in remitted (the absence of panic attack (PA) symptoms for at least 6 months) PD patients compared to normal control (NC) subjects. METHODS: Before and after audiovisual stimulation (AS) that induced mental stress through exposure to video images of high stress experiences, such as driving motor vehicles, the pupillary light reflex (PLR) was measured with an infrared pupillometer in 30 remitted PD patients and 30 age- and gender-matched NC subjects. In order to examine the relationships between the 8 PLR parameters (initial pupillary diameter in darkness, pupillary diameter at maximum constriction, constriction ratio, latency of the reflex, time to reach maximum constriction and time constant of redilation) and state/trait anxiety, we used the State-Trait Anxiety Inventory (STAI) and stepwise multiple regression analysis. RESULTS: There was no significant group difference in the STAI-T score and STAI-S scores before and after AS. We confirmed the significant relationships between pupillary function and state/trait anxiety in NC subjects, but not in PD patients. CONCLUSIONS: These findings suggest that in contrast to NCs, even remitted PD patients may have dysfunctional PLR regulation with mental loading, such as AS. Moreover, it is possible that the abnormalities of ANS exist extensively in PD, since almost all panic symptoms, including PA, are involved in cardiovascular symptoms, but not pupillary ones.     

Facial reactions, autonomic activity and experienced emotion: a three component model of emotional conditioning

The present study was designed to evaluate whether aversively conditioned responses to facial stimuli are detectable in all three components of the emotional response system, i.e. the expressive/behavioral, the physiological/autonomic and the cognitive/experienced component of emotion. Two groups of subjects were conditioned to angry or happy facial expression stimuli using a 100 dB noise as UCS in a differential aversive conditioning paradigm. The three components of the emotional response system were measured as: Facial-EMG reactions (corrugator and zygomatic muscle regions); autonomic activity (skin conductance, SCR; SCR half recovery time, T/2; heart rate, HR); and ratings of experienced emotion. It was found that responses in all components of the emotional response system were detectable in the angry group as greater EMG and autonomic resistance to extinction and greater self-reported fear. More specifically the angry group showed a resistant conditioning effect for the facial-EMG corrugator muscle that was accompanied by resistant conditioning for SCR frequency, slower SCR recovery, resistant conditioning in HR and a higher self-reported fear than the happy group. Thus, aversive conditioning to angry facial stimuli induce a uniform negative emotional response pattern as indicated by all three components of the emotional response system. These data suggest that a negative 'affect program' triggers responses in the different emotional components. The results suggest that human subjects are biologically prepared to react with a negative emotion to angry facial stimuli.     

Blood pressure reaction to negative stimuli: Insights from continuous recording and analysis

Individuals with a tendency toward abnormally enhanced cardiovascular responses to stress are at greater risk of developing essential hypertension later in life. Accurate profiling of continuous blood pressure (BP) reactions in healthy populations is crucial for understanding normal and abnormal emotional reaction patterns. To this end, we examined the continuous time course of BP reactions to aversive pictures among healthy participants. In two experiments, we showed participants negative and neutral pictures while simultaneously measuring their continuous BP and heart rate (HR) reactions. In this study, BP reactions were analyzed continuously, in contrast to previous studies, in which BP responses were averaged across blocks. To compare time points along a temporal continuum, we applied a multi-level B-spline model, which is innovative in the context of BP analysis. Additionally, HR was similarly analyzed in order to examine its correlation with BP. Both experiments revealed a similar pattern of BP reactivity and association with HR. In line with previous studies, a decline in BP and HR levels was found in response to negative pictures compared to neutral pictures. In addition, in both conditions, we found an unexpected elevation of BP toward the end of the stimuli exposure period. These findings may be explained by the recruitment of attention resources in the presence of negative stimuli, which is alleviated toward the end of the stimulation. This study highlights the importance of continuous measurement and analysis for characterizing the time course of BP reactivity to emotional stimuli.     

Motor activity and autonomic cardiac functioning in major depressive disorder

BACKGROUND: The daily pattern of motor activity and the autonomic cardiovascular regulation were studied in major depression to quantify changes in psychomotor function and autonomic cardiac functioning. Additionally, relationships between motor activity parameters, cardiovascular measures and specific clinical features were examined. METHODS: Wrist-actigraphy was used to monitor 24-h motor activity for 67 unmedicated (unipolar) depressed inpatients and 64 control subjects. During supine rest, spectral analysis was applied to assess HR and SBP variability, a baroreflex sensitivity (BRS) index and the respiratory frequency, in addition to mean heart rate (HR) and blood pressure (BP) levels for the patient group and a second control group (N=51). RESULTS: The patients showed a lower motor activity level and a reduced fragmentation of motor activity during wake, and a higher motor activity level and a decreased immobility during sleep. The mean HR and DBP level and the respiratory frequency were higher in the patient group than in the control group, but no differences in HR and SBP variability or BRS were found. Furthermore, motor activity parameters and cardiovascular measures of the patients were related to agitation and retardation and overall, patients with lower motor activity levels demonstrated lower SBP levels. CONCLUSIONS: This study confirms that the 24-h pattern of motor activity is altered in unmedicated depressed inpatients, but limited evidence was found for an autonomic cardiac dysfunction. Within the patient group there were relationships between motor activity parameters, cardiovascular measures, and clinical features, but the underlying neurobiological pathways need to be further explored.     

Autonomic arousal in adults who stutter prior to various reading tasks intended to elicit changes in stuttering frequency

This study examined relationships between anticipatory autonomic arousal and stuttering in four reading tasks. 13 adult persons who stutter (PWS) reported their ‘feared’ (expected to elicit more stuttering) sounds. They read phrases initiated by feared (F) and neutral (N) phonemes. Both stimuli sets were read solo (S) and with choral accompaniment (C), creating FS, FC, NS, and NC conditions. Skin conductance (SC) and heart rate (HR) measures were made during a 9 s window that followed stimulus presentation and preceded speaking. Only SC measures produced significant differences across conditions. Choral conditions produced decreases in SC measures and stuttered trials. Feared conditions produced increases in SC but not stuttering. HR measures were variable, undifferentiated by condition, but produced a gradually increasing triphasic response pattern. No differences in anticipatory SC or HR measures were found in stuttered versus fluent trial comparisons. However, the NC condition, which eliminated stuttering, produced significantly lower SC measures than the fluent utterances in the other conditions (FS, FC, NS). Furthermore, SC measures from the fluent and stuttered trials were similar in these three conditions. These findings suggest that anticipatory autonomic arousal is better differentiated by the possibility of stuttering than by a fluent/stuttered speech outcome. Trials that produced anticipatory SC responses showed greater final HR deceleration, suggesting autonomic coactivation, a response pattern that is associated with aversive stimuli and herein, likely indicative of speech-related state anxiety. However, these physiological markers of anxiety appear to be neither necessary nor sufficient to induce observable stuttering.     

Autonomic Responsively to Sensory Stimulation in Drug Addicts

Skin conductance responses (SCRs), heart rate (HR). arterial blood pressure (BP), and respiration were recorded under rest and sensory stimulation (11 Hz strobe light, 100 dB while noise) in former drug addicts (DC) and in controls (CG) matched for sex and age in a repeated measures design, DC consisted of long-term users of barbiturates and narcotic analgesics and had been free of drugs for 11 period of 3 wks prior to the first session. The hypothesis was tested that autonomic functions art decreased in DG due to the drug effects. In various ANOVAs significant main effects for all factors were found. The results in DG compared to CG were: (1) diastolic hut not systolic BP was significantly lower: (2) SCR magnitudes were. Significantly smaller during rest periods; (3) SCR magnitudes and SCR recruitment latencies were significantly smaller in both sessions to visual and auditory stimuli; i4 the habituation rates of SCR magnitudes and SCR recruitment latencies were significantly greater at stimulus offset. The results of SCRs and diastolic BP indicated a decreased autonomic activity in the drug dependents compared to the controls.     

Sleep and cardiovascular phenotype in middle‐aged hypocretin‐deficient narcoleptic mice

Narcolepsy with cataplexy (NC) is a lifelong disorder caused by loss of hypothalamic hypocretin/orexin (HCRT) neurones, often starting in childhood. NC patients show altered control of heart rate (HR) and a normotensive non‐dipper blood pressure (BP) profile, but the natural history and prognostic significance of these alterations remain unclear. Similar alterations have been observed in HCRT‐ataxin‐3 transgenic (TG) NC mice lacking HCRT neurones, but studies have been limited to young adult individuals <4 months of age. Here we evaluated long‐term effects of NC on derangements in the wake–sleep state and cardiovascular control by studying middle‐aged TG. We chronically instrumented TG and wild‐type mice aged 10–11 months with electrodes for sleep scoring and a telemetric transducer for BP and HR measurements. We then recorded mice in freely behaving conditions. TG showed a NC phenotype including fragmentation of wakefulness, reduced latency to rapid eye movement sleep (REMS) and cataplexy‐like events. TG also showed blunted BP decline on entering non‐rapid eye movement sleep (NREMS), enhanced BP increase on passing to REMS, increased HR, and blunted changes in HR upon arousal and awakening from NREMS. Histological and ultrastructural analysis of cardiovascular and renal tissue did not reveal evidence of subclinical hypertensive organ damage. These data indicate that HCRT neurone loss in TG causes alterations in wake–sleep behaviour and cardiovascular control that are not peculiar to the beginning of the disease but are maintained at least up to middle age. These alterations are similar to those in adult NC patients, but do not produce early subclinical damage to the heart and kidneys.     

Enhanced emotion-induced amnesia in borderline personality disorder

BACKGROUND: Current biological concepts of borderline personality disorder (BPD) emphasize the interference of emotional hyperarousal and cognitive functions. A prototypical example is episodic memory. Pre-clinical investigations of emotion-episodic memory interactions have shown specific retrograde and anterograde episodic memory changes in response to emotional stimuli. These changes are amygdala dependent and vary as a function of emotional arousal and valence. METHOD: To determine whether there is amygdala hyper-responsiveness to emotional stimuli as the underlying pathological substrate of cognitive dysfunction in BPD, 16 unmedicated female patients with BPD were tested on the behavioural indices of emotion-induced amnesia and hypermnesia established in 16 healthy controls. RESULTS: BPD patients displayed enhanced retrograde and anterograde amnesia in response to presentation of negative stimuli, while positive stimuli elicited no episodic memory-modulating effects. CONCLUSION: These findings suggest that an amygdala hyper-responsiveness to negative stimuli may serve as a crucial aetiological contributor to emotion-induced cognitive dysfunction in BPD.     

Examining the Role of Anxiety Sensitivity in Sleep Dysfunction Across Anxiety Disorders

Anxiety Sensitivity (AS) has been associated with sleep difficulties in certain anxiety disorder populations, but no studies have examined cross-diagnostically the role of anxiety sensitivity in sleep dysfunction. Three hundred one participants with generalized anxiety disorder (GAD), social anxiety disorder (SAD), and panic disorder (PD) completed an ancillary questionnaire-based study. Linear regression was used to examine AS and sleep dysfunction, and mediation analyses were used to examine whether AS was a mediator of the effect of primary diagnosis on sleep. AS was associated with increased sleep dysfunction across anxiety disorders, and primary anxiety disorder diagnosis was significantly associated with sleep dysfunction. However, after controlling for AS, primary diagnosis was no longer significant. AS significantly mediated the effects of PD versus SAD and of PD versus GAD on sleep dysfunction, but did not significantly mediate the effect of GAD versus SAD on sleep dysfunction. Taken together, AS appears to be a more important predictor of sleep dysfunction overall, emphasizing the cross-diagnostic nature of AS and bolstering the RDoC initiative approach for treating psychological dysfunction.     

Strange feelings: do amygdala abnormalities dysregulate the emotional brain in schizophrenia?

Schizophrenia is widely regarded to be a neurocognitive disorder, i.e. a dysfunction of the neural and cognitive systems subserving thinking and reasoning, memory, language, attention and perception. However, although cognitive dysfunction is certainly a cardinal feature of schizophrenia, we argue that dysfunction of emotional brain systems may be even more important in understanding the disorder. Indeed, in recent years research on the emotional aspects of schizophrenia is accumulating at a high rate. Here, we review the available evidence regarding behavioral and neural manifestations of abnormal emotional systems in schizophrenia. This evidence comes from patient studies using tasks of emotion recognition, emotional expression and emotional experience. Furthermore, studies of schizophrenia patients using structural MRI have demonstrated volume reductions of the amygdala, a key structure of the emotional brain. Finally, functional fMRI studies have revealed an attenuated response of the amygdala to emotional stimuli as compared to neutral stimuli. Beyond demonstrating that dysfunction of the emotional brain is a hallmark of schizophrenia, we propose a model that integrates previous neural accounts of emotional abnormalities in schizophrenia, and specifies a neural basis for differential emotional correlates of positive and negative symptoms. Specifically, a lesion to the amygdala in combination with reduced interconnectivity with the prefrontal cortex is hypothesized to give rise to reduced emotional expression (affective flattening) and emotion recognition deficits. In contrast, an imbalance in dopamine systems may underlie increased anxiety and autonomic arousal, and the assignment of emotional salience to insignificant stimuli, associated with psychosis. We also hypothesize that the central and basolateral nuclei of the amygdala may contribute differentially to these abnormalities.     

Simulation of the geomagnetic field experienced by the International Space Station in its revolution around the Earth: effects on psychophysiological responses to affective picture viewing

There is evidence suggesting that exposure to an abnormal magnetic environment may produce psychophysiological effects related to abnormalities in responses to stress. This may be of relevance for space medicine where astronauts are exposed to a magnetic field different from that exerted by the Earth. Aim of this study was to assess how the exposure of the head to a magnetic field simulating the one encountered by the International Space Station (ISS) during a single orbit (90 min) around the Earth affects the cardiovascular and psychophysiological parameters. Twenty-four human volunteers were studied double blindly in random order under sham and magnetic exposure. During exposure, the persons were shown a set of pictures of different emotional content while subjective self-rating, skin conductance (SC), blood pressure (BP), and heart rate (HR) were measured. In addition, BP, HR, and tooth pain threshold were assessed before and after exposure. While subjects were under magnetic exposure, skin conductance was strongly differentiated (F_2,36 = 22.927; p = 0.0001), being high during emotionally involving (positive and negative) pictures and low during neutral pictures. Conversely, when subjects were under sham exposure, no significant differences were observed. There was, however, a trend for higher heart rate during picture viewing under magnetic exposure as compared to sham exposure. No effects were found for the other variables. These results suggest that an abnormal magnetic field that simulates the one encountered by ISS orbiting around the Earth may enhance autonomic response to emotional stimuli.     

Diabetic autonomic neuropathy: Abnormal cardiovascular reactions under general anesthesia

Summary The influence of diabetic autonomic neuropathy upon the behavior of the circulatory system was investigated in 56 patients who had undergone ophthalmological surgery. A standardized test combination (variability in heart rate during deep breathing, Valsalva ratio, 3015 ratio, change in blood pressure from lying to standing, sustained handgrip test) was used to study the patients' cardiovascular reflectory reactions. The patients were then divided into the following groups: Group I, non-diabetics Group II, diabetics without autonomic neuropathy Group III, diabetics with autonomic neuropathy The anesthetic (induction by barbiturates and conduction by inhalation agents) and the surgical procedure (pars plana vitrectomy) were standardized and always identical. During anesthesia patients in group III experienced hypotensive reactions (systolic blood pressure below 90 mm Hg) significantly more often (72.2%) than patients in group I (25%). In order to achieve stability in blood pressure the patients of group III had to be given vasoactive drugs much more often (77.8%) than the patients of group I (12.5%) and those of group II (35.7%). We found a significant correlation between the degree of autonomic dysfunction and the largest drop in blood pressure under narcosis (r=–0.60,P<0.001). However, marked variability in heart rate and cardiac rhythm disorders during anesthesia were seen only in patients of groups I and II. These results prove the atypical hemodynamic behavior and especially the extreme instability in blood pressure in diabetic autonomic neuropathy under general anesthesia. Therefore we consider it to be very helpful to check the cardiovascular reflectory status of diabetics preoperatively.Abbreviations AN autonomic neuropathy - AV atrioventricular - BP blood pressure - bpm beats per minute - cm centimeter - f female - HR heart rate - m male - PD diastolic blood pressure - PS systolic blood pressure     

The role of the right hemisphere in the physiological and cognitive components of emotional processing

Right hemisphere specialization for emotional processing was investigated using behavioral and psychophysiological methods, Fifty undergraduates were shown slides depicting negative emotional and neutral scenes briefly lateralized to the right or left cerebral hemispheres and asked to categorize each as emotional or neutral. Pulse volume and heart rate (HR) measured physiological processing and reaction time measured cognitive processing. The largest vasoconstriction responses and HR deceleration were obtained for emotional items in the right hemisphere. However, reaction time failed to show right hemisphere superiority in perceptual/cognitive processing, demonstrating instead slowest responses to emotional stimuli presented to the right hemisphere together with evidence for left hemisphere competence. Selective right hemispheric activation in autonomic responses, combined with the lack of right hemisphere specialization in the cognitive task, suggests that the physiological response system rather than the perceptual/cognitive system is the locus of the right hemisphere superiority for emotion.     

Automation of analysis of cardiovascular autonomic function from chronic measurements of arterial pressure in conscious rats

At present, there is no single software package that provides a comprehensive power spectral analysis of pulse interval (PI) and arterial blood pressure (BP), spontaneous cardiac baroreceptor reflex gain (sBRG) and respiratory rate. Furthermore, scientific validation of the software that is currently commercially available and employed has not been published. We introduce 'Hey-Presto' software, which fully evaluates cardiovascular autonomic function from the BP signal obtained from rats. The program performs power spectral analysis of HR and BP variability, respiratory rate and, based on a time-series method, spontaneous cardiac baroreceptor (sBRG). We have validated Hey-Presto with conventional pharmacological agents to block cardiac vagal and cardiac sympathetic transmission in conscious rats fitted with a radio-telemetery BP transducer. Following administration of atropine (1 mg kg(-1), I.V.), high-frequency (HF) power of the PI decreased (P < 0.01) and was associated with the expected increase in HR. Subsequent cardiac sympathetic blockade (atenolol, 1 mg kg(-1), I.V.) reduced the low frequency (LF) to HF ratio (LF:HF) of the PI (P < 0.01), which was consistent with the observed reduction in HR. We also found that alterations in sBRG after blockade of cardiac autonomic transmission were highly comparable to values computed manually using vasoactive drugs administered intravenously. The software also detected circadian rhythms in sBRG, HF component of the PI, LF:HF of the PI and LF component of the BP as well as BP and HR during continuous 24 h recording. By demonstrating its application to humans, we found appropriate changes in the power of PI and the LF power of the BP during postural changes. These results demonstrate that Hey-Presto allows a fully automated, reliable, fast and comprehensive evaluation of cardiovascular autonomic function based on chronic measurements of BP in rats. Moreover, we have confirmed its versatility by demonstrating its application to man.     

Cardiorespiratory and autonomic interactions during snoring related resistive breathing

STUDY OBJECTIVES: We hypothesized that blood pressure (BP) is less during snoring as compared to periods of non-snoring in non-apneic individuals. Furthermore, we hypothesized that this reduction may be accompanied by a simultaneous decrease in sympathetic (SNSA) and parasympathetic (PNSA) nervous system activity and an increase in heart rate (HR). DESIGN: N/A. SETTING: N/A. PATIENTS OR PARTICIPANTS: N/A. MEASUREMENTS: The variables mentioned above in addition to breathing frequency were measured in 9 subjects during NREM sleep. In addition, the lowest systolic (SBP) and diastolic blood pressure (DBP) during inspiration and the highest SBP and DBP during expiration was determined breath-by-breath from segments selected from each NREM cycle. Heart rate variability was used as a marker of autonomic nervous system activity. RESULTS: Our results showed that BP during snoring decreased compared to non-snoring and the breath-by-breath BP analysis suggested that this difference may have been mediated by changes in intrathoracic pressure. In conjunction with the decrease in BP, SNSA decreased and HR increased however PNSA remained constant. Thus, a decrease in PNSA was likely not the primary mechanism responsible for the HR response. CONCLUSIONS: We conclude that BP responses and SNSA during snoring are similar to that reported previously in non-snoring individuals. However, the causal mechanisms maybe different and manifested in other measures such as HR. Thus, nocturnal cardiovascular and autonomic function maybe uniquely different in non-apneic snoring individuals.     

Adrenergic mechanisms and blood pressure regulation in diabetes mellitus

Summary Changes in blood pressure (BP) and plasma norepinephrine (NE) following various stimuli of the sympathetic nervous system were studied in six healthy subjects and in 17 diabetic patients. The latter were subdivided in three groups: (1) six patients with neither peripheral neuropathy nor autonomic dysregulation, (2) six patients with severe peripheral neuropathy without autonomic dysregulation, and (3) five patients with autonomic dysregulation, three of whom suffered also from peripheral neuropathy. The following procedures were performed: (1) cold pressor test (2 min), (2) mechanical irritation of the skin by suction (0.75 kg/cm², 10 min), (3) orthostasis (10 min), and (4) i.v. infusion of NE (50, 100, 200 ng kg^–1 min^–1 for 15 min each). Both the stimulated endogenous plasma NE levels and BP response to exogenous NE were the same in normal subjects, in diabetic controls and in diabetics with peripheral neuropathy without autonomic dysregulation. In contrast, diabetics with postural hypotension showed a less pronounced release of NE to standing (P<0.05), but not to cold pressor test and mechanical skin irritation. Furthermore, they showed increased vasoreactivity to the highest dose (P<0.05), but not to the lower doses of exogenous NE. Thus NE release and adrenergic BP regulation seem to be altered only in diabetics with clinical signs of autonomic dysregulation. These alterations can only be evaluated when patients are exposed to stimuli of higher intensity, such as orthostasis or infusion of a high NE dose.     

Seasonal training and heart rate and blood pressure variabilities in young swimmers

To evaluate if changes in athletes’ physical fitness due to seasonal training are associated with changes in cardiovascular autonomic control, nine swimmers (three males and six females; aged 14–18 years) were evaluated before and after 5 months of training and competitions. Maximal oxygen consumption and ventilatory threshold were determined during a maximal test; heart rate (HR) and blood pressure (BP) variabilities’ power spectra were calculated at rest (supine and sitting positions) and in the recovery of two exercises at 25 and 80% pre-training At the end of the season: (a) and ventilatory threshold increased respectively by 12 and 34% (P<0.05); (b) at rest, HR decreased by 9 b min⁻¹ in both body positions, whereas BP decreased in supine position only by 17%. No change in low frequency (LF, 0.04–0.15 Hz) and high frequency (HF, 0.15–1.5 Hz) normalized powers and in LF/HF ratio of HR variability and in LF power of systolic BP variability was observed. In contrast, a significant increase in HF α-index (about 12 ms mmHg⁻¹) was found; (c) during recovery no change in any parameter was observed. Seasonal training improved exercise capacity and decreased resting cardiovascular parameters, but did not modify vagal and sympathetic spectral markers. The increase in α-index observed at rest after the season and expression of augmented baroreflex sensibility indicated however that HR vagal control could have been enhanced by seasonal training. These findings suggested that autonomic system might have played a role in short-term adaptation to training.