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PubMed1976

Parameters of the three-pool model of the turnover of plasma cholesterol in normal and hyperlipidemic humans.

Long-term studies (32-49 wk) of the turnover of plasma cholesterol were conducted in 24 subjects. Eight subjects were normilipidemic, six had hypercholesterolemia, eight had hypercholesterolemia and hypertriglyceridemia, and two had hypertriglyceridemia alone. 10 of the hyperlipidemic patients had a definite familial disorder. In all subjects (except one for whom complete data were not available), the same three-pool model previously described gave the best fit for the data. The parameters of the three-pool model observed in the normal subjects were compared with the model parameters found in the patients with the different kinds of hyperlipidemia. In addition, single and multiple regression analyses were conducted to explore the relationships between the model parameters and various physiological variables, including age, body size, and serum lipid concentrations. Using this approach, significant differences between groups, or correlations with serum lipid levels were seen for several parameters of the three-pool model: the production rate (PR); the size of the rapidly exchanging pool 1 (M1); all estimates of the size of the most slowly equilibrating pool 3 (M3); and the rate constant k21. The PR in normal subjects (1.14 +/- 0.19 g/day, mean +/- SD) was not significantly different from that found in patients with hypercholesterolemia, with or without hypertriglyceridemia. The major determinant of cholesterol PR was overall body size, expressed either as total body weight or as surface area. The correlations between PR and indices of adiposity (percent ideal weight and excess weight), although statistically significant, were much weaker in this nonobese population. After adjustment for body size variation, cholesterol PR was not correlated with the serum cholesterol concentration but was probably (P less than 0.05) correlated with the triglyceride concentration. When the two patients with very high triglyceride concentrations were excluded, however, no correlation was observed between adjusted PR and triglyceride level. It is probable that hypertriglyceridemic patients represent a heterogeneous population, in which the majority do not show increased cholesterol PR. M1 was correlated with all body size variables, but most strongly with excess weight. After adjusting for the effects of body size, M1 was also correlated and triglyceride. Major differences were found in the relationships between the physiological variables and the sizes of pools 2 and 3. M2 was correlated neither with any of the indices of body size or adiposity, nor with the serum levels of either cholesterol or triglyceride. In contrast, all estimates of M3 were correlated with indices of adiposity (but not of overall body size) and with the serum cholesterol concentration. Thus, the amount of cholesterol in slowly equilibrating tissue sites appears to particularly increase with elevations of the serum cholesterol level. The results also confirm previous data that adipose tissue cholesterol is an important part of pool 3.

Adipose Tissue↗

PubMed2006

The relationship between the lactate turnpoint and the time at VO2max during a constant velocity run to exhaustion.

The present investigation examined the relationship between the running velocity at the lactate turnpoint (vLTP) and the time at which VO2max can be sustained (TVO2max) during a continuous run to exhaustion at the minimal running velocity that elicits VO2max (vVO2max). Seven moderately-trained endurance runners undertook three tests on a treadmill. The first test was to determine vVO2max; the second to determine the time to exhaustion during a constant velocity run at vVO2max (Tlim vVO2max) and TVO2max; and the third to determine the vLTP. Pearson's correlation coefficient was used to determine the association between the vLTP (%vVO2max; i.e. the relative vLTP) and TVO2max, and between other selected physiological variables. Correlations between the relative vLTP and TVO2max, expressed as a percentage of T(lim vVO2max (the relative TVO2max; r=0.82), and between TVO2max and Tlim vVO2max (r=0.89), were significant at the p<0.05 level. All other correlations between selected measured physiological variables were found to be statistically insignificant. The main finding of this present study is that the relative vLTP demonstrated a significant positive correlation with the relative TVO2max. The physiological mechanism by which the lactate turnpoint may influence the relative TVO2max has not been elucidated, but may be due to a combination of decreasing the time to attain VO2max and increasing Tlim vVO2max. The present investigation has demonstrated that the lactate turnpoint may influence the relative time at which VO2max can be sustained during a continuous run to exhaustion at vVO2max, although further research is required to substantiate these findings.

Adult↗

PubMedDate not supplied

Factors influencing successful discontinuance of mechanical ventilation after open heart surgery: a clinical study of 41 patients.

Circulatory, respiratory, and metabolic variables were measured with a mobile clinical bedside unit in 41 patients during the first 48 hours after open heart surgery. Calculations were carried out off-line by a computer program. The variables were measured during controlled mechanical ventilation and compared with those obtained during spontaneous breathing and after resumption of mechanical ventilation; attempts at spontaneous breathing were categorized as successful or unsuccessful. The variables were compared before, during, and after the successful and the unsuccessful attempts at spontaneous breathing. In the series as a whole, the onset of spontaneous breathing was characterized by increases in cardiac output, radial arterial and pulmonary arterial pressures, and mixed venous oxygen tension (PVO2) and content (CVO2), as well as diminished arterial and mixed venous oxygen content differences (avDO2); no significant changes in oxygen consumption (VO2) were seen. Unsuccessful attempts disturbed the patient's physiological equilibrium by reducing oxygen delivery and not increasing VO2, while increasing ventilatory work. In general, resumption of controlled ventilation restored the physiological variables to their control conditions. Successful attempts at spontaneous breathing did not greatly affect the physiological variables. The indication for resumption of controlled ventilation after periods of spontaneous breathing is the combination of increased ventilatory work with diminished circulatory and respiratory functions.

Adolescent↗

PubMed1994

Long-term results of postanal repair for neurogenic faecal incontinence.

Between 1984 and 1986, 54 patients underwent postanal repair for neurogenic faecal incontinence. Forty-two (41 women) were available for follow-up 5-8 (median 6.2) years after operation. Of these, 34 women attended for clinical and anorectal physiological assessment. Anal endosonography was also performed in 30 patients. In the 34 patients examined, continence categories (Browning and Parks' classification) of C (n = 12) and D (n = 22) before surgery became A (n = 2), B (n = 12), C (n = 16) and D (n = 1) at 6 months and A (n = 4), B (n = 5), C (n = 21) and D (n = 4) at 5-8 years. Nine patients therefore had continence for solids and liquids, five of whom were incontinent to flatus, in the long term. Assessment of outcome by patients revealed long-term improvement in 28 and no change in six. Two of the 34 patients assessed were housebound because of incontinence. Of the total of 54 patients, only one required a stoma. The length of the anal canal increased significantly from a preoperative median (range) of 2.0 (1.5-4.0) cm to 3.8 (1.8-5.5) cm 5-8 years after surgery. Perineal descent at rest decreased markedly. Progression of neuromuscular damage was demonstrated by prolongation of the pudendal nerve terminal motor latency from a median (range) 2.38 (1.80-3.35) ms to 2.80 (2.20-4.25) ms and increasing median (range) fibre density in the external sphincter, from 1.86 (1.76-2.40) to 3.63 (2.03-6.20). The pudendal nerve terminal latency was the only preoperative physiological variable that correlated significantly with long-term outcome (A and B 2.20 ms versus C and D 2.65 ms, P < 0.05). At long-term assessment, maximal anal squeeze pressure was the only physiological variable that correlated significantly with clinical outcome. Anal endosonography revealed a clinically undetected sphincter defect in 19 of 30 patients examined but the presence of a defect did not relate to clinical outcome.

Adult↗

PubMed2006

A closed-loop hybrid physiological model relating to subjects under physical stress.

OBJECTIVE: The objective of this research study is to derive a comprehensive physiological model relating to subjects under physical stress conditions. The model should describe the behaviour of the cardiovascular system, respiratory system, thermoregulation and brain activity in response to physical workload. METHODS AND MATERIAL: An experimental testing rig was built which consists of recumbent high performance bicycle for inducing the physical load and a data acquisition system comprising monitors and PCs. The signals acquired and used within this study are the blood pressure, heart rate, respiration, body temperature, and EEG signals. The proposed model is based on a grey-box based modelling approach which was used because of the sufficient level of details it provides. Cardiovascular and EEG Data relating to 16 healthy subject volunteers (data from 12 subjects were used for training/validation and the data from 4 subjects were used for model testing) were collected using the Finapres and the ProComp+ monitors. For model validation, residual analysis via the computing of the confidence intervals as well as related histograms was performed. RESULTS: Closed-loop simulations for different subjects showed that the model can provide reliable predictions for heart rate, blood pressure, body temperature, respiration, and the EEG signals. These findings were also reinforced by the residual analyses data obtained, which suggested that the residuals were within the 90% confidence bands and that the corresponding histograms were of a normal distribution. A higher intelligent level was added to the model, based on neural networks, to extend the capabilities of the model to predict over a wide range of subjects dynamics. CONCLUSION: The elicited physiological model describing the effect of physiological stress on several physiological variables can be used to predict performance breakdown of operators in critical environments. Such a model architecture lends itself naturally to exploitation via feedback control in a 'reverse-engineering' fashion to control stress via the specification of a safe operating range for the psycho-physiological variables.

Cardiovascular System↗

PubMed1982

Variability of hematocrit value, blood serum beta- and gamma-globulin level and body weight in different transferrin genotypes of common vole (Microtus arvalis, Pallas 1779) from natural population.

1. Heterozygotes TfF/TfE of voles did not differ in body weight, they had higher hematocrit value (males and females), higher beta-globulin fraction (males) or higher gamma-globulin fraction (females). 2. A smaller variability of parameters studied was observed in heterozygotes than in homozygotes. Small and similar variability occurred in hematocrit value and beta-globulins while higher variability occurred in body weight and gamma-globulins. 3. In common voles the faster migrating E system of transferrin may have a higher capacity for iron transport than the F system. 4. Seasonal changes of hematocrit value in vole populations seems to result from genetical and physiological variability. 5. Sexual and seasonal changes in beta-globulin level appear to be related to changes in sexual activity of the animals during the seasons. 6. In autumn, low weight of animals and high serum gamma-globulin level, with the same physiological variability of these two parameters, suggest the synthesis of gamma-globulins with tissue (muscle) proteins. 7. Autumnal increase of gamma-globulin level seems to be very important, taking into consideration the role of the protein in water retention and its filtration from the tissues. Very high level of the protein fraction may play a role in winter high mortality of voles.

Animals↗

PubMed1995

A porcine model for evaluation of cerebral haemodynamics and metabolism during increased intracranial pressure.

In patients with severe head injuries raised intracranial pressure (ICP) constitutes the most important cause of mortality. Several new therapies for increased ICP have recently been suggested and it is of importance to study the physiological effects of these treatments in animal experiments during steady state conditions. A porcine model for evaluation of cerebral haemodynamics and metabolism during increased ICP is presented. Intracranial hypertension was induced by inflation of two tonometric gastric balloons placed extradurally covering a major part of the parietooccipital region bilaterally. The distribution of the blood flow supplied by the carotid artery used for the cerebral blood flow (CBF) measurements was studied by intraarterial (i.a.) injection of 99mTc-HMPAO. The measurements showed that following ligation of the external carotid and the occipital artery no accumulation of tracer substance occurred in extracranial tissues during normal or increased ICP. Cerebral physiological variables (CBF, Cavo2, and ICP) were measured 5, 20 and 60 min after induction of intracranial hypertension. The results confirm that the experimental situation gives a reproducible increase in ICP (25-28 mm Hg) and that the physiological variables remain stable during the period of intracranial hypertension. We conclude that the model simulates the effects of an acute intracranial focal mass and is well suited for the evaluation of different pharmacological therapies of increased ICP.

Animals↗

PubMed1993

Variability of physiologically based pharmacokinetic (PBPK) model parameters and their effects on PBPK model predictions in a risk assessment for perchloroethylene (PCE).

When used in the risk assessment process, the output from physiologically based pharmacokinetic (PBPK) models has usually been considered as an exact estimate of dose, ignoring uncertainties in the parameter values used in the model and their impact on model predictions. We have collected experimental data on the variability of key parameters in a PBPK model for tetrachloroethylene (PCE) and have used Monte Carlo analysis to estimate the resulting variability in the model predictions. Blood/air and tissue/blood partition coefficients and the interanimal variability of these data were determined for tetrachloroethylene (PCE). The mean values and variability for these and other published model parameters were incorporated into a PBPK model for PCE and a Monte Carlo analysis (n = 600) was performed to determine the effect on model predicted dose surrogates for a PCE risk assessment. For a typical dose surrogate, area under the blood time curve for metabolite in the liver (AUCLM), the coefficient of variation was 25% and the mean value for AUCLM was within a factor of two of the maximum and minimum values generated in the 600 simulations. These calculations demonstrate that parameter uncertainty is not a significant potential source of variability in the use of PBPK models in risk assessment. However, we did not in this study consider uncertainties as to metabolic pathways, mechanism of carcinogenicity, or appropriateness of dose surrogates.

Administration, Inhalation↗

PubMed2006

Continuous ratings of breathlessness during exercise by children and young adults with asthma and healthy controls.

Although it is recommended and common practise for adults with respiratory disease to rate symptoms (e.g., dyspnea and/or leg discomfort) during exercise testing, there are no reports on whether children can rate their perception of breathlessness during exercise. Our aims were to evaluate the ability of children and young adults with asthma to continuously rate breathlessness on the 0-10 category-ratio (CR-10) scale with a computerized system during cycle ergometry, and to compare their results with those of healthy subjects. At an initial visit, subjects were familiarized with equipment and exercise protocol, and practised rating breathlessness while cycling. At a follow-up visit (2-4 days later), subjects performed incremental exercise and rated breathlessness using a computer system, mouse, and monitor. Changing the position of the mouse caused movement of a vertical bar located adjacent to the CR-10 scale to indicate the severity of breathlessness. Baseline characteristics of the 14 subjects with asthma (age, 15 +/- 3 years) and 33 healthy subjects (age, 16 +/- 2 years) were similar. The two groups had comparable levels of fitness as measured by peak oxygen consumption (VO(2)). Correlations between exercise physiologic variables (power production, VO(2), and minute ventilation) and breathlessness ratings were >0.90. Subjects reported progressively more ratings of breathlessness with increasing exercise intensities. There were no differences between groups for slopes, x-intercepts, and absolute thresholds relating physiologic variables and breathlessness. In conclusion, children and young adults with asthma as well as healthy individuals of comparable age successfully used the computerized system to rate breathlessness continuously during cycle ergometry. Both groups reported more ratings of breathlessness with this technique as exercise progressed.

Adolescent↗

PubMed1993

Interstitial pressure of subcutaneous nodules in melanoma and lymphoma patients: changes during treatment.

Interstitial pressure (IP) is a physiological variable that may have its greatest influence on the transport of high-molecular-weight therapeutic agents. IP in tumor nodules was measured in patients with metastatic melanoma or non-Hodgkin's lymphoma to determine the influence of this physiological variable on treatment outcome. The wick-in-needle technique was used to measure IP at time points before and after treatment with a variety of immunotherapy and chemotherapy regimens. Selected patients had IP measurements during chemotherapy or immunotherapy infusions. Ultrasound or computed tomography was used to evaluate the size of the studied lesions and their relationship to normal structures. The mean baseline IP in melanoma nodules (n = 22) and lymphoma nodules (n = 7) was 29.8 and 4.7 mm Hg, respectively (P = 0.013 for the difference between tumor types). In a subset of melanoma nodules for which IP had been measured before and after treatment, the IP increased significantly over time for nonresponding melanoma lesions from a baseline of 24.4 to 53.9 mm Hg after treatment (P = 0.005) and decreased in melanoma lesions that responded to treatment where the mean baseline and post-treatment IPs were 12.2 and 0 mm Hg, respectively (P = 0.001 for the difference in IP profiles between responding and nonresponding lesions). Six of seven lymphoma nodules responded completely to chemotherapy or radiation. The single nodule that did not respond had a baseline IP of 1 mm Hg that increased to 30 mm Hg after treatment. Tumor IP differs significantly between melanoma and non-Hodgkin's lymphoma. The changes in IP over time differ significantly between responding and nonresponding melanoma lesions. IP that increases during treatment appears to be associated with tumor progression in these tumor types.

Adult↗

PubMed1996

Effects of high- and low-energy meals on hunger, physiological processes and reactions to emotional stress.

The effects of a reduced energy content of two meals on hunger motivation, physiological variables and reactions to emotional stress were investigated. Healthy normal-weight male students received breakfast and lunch in the laboratory. Half of the subjects (n = 28) received meals with normal energy content (1700 kcal), and half received meals with reduced energy content (260 kcal). Psychological and physiological variables were obtained for 8 h from morning to afternoon, including during a period of emotional stress in the afternoon. Psychophysical state was altered by the reduction of energy in food (e.g. increased subjective motivation to eat, decreased systolic blood pressure). Noise decrease feelings of relaxation in subjects who had received low-energy meals, but not in subjects who had received high-energy meals. This enhanced emotional reactivity after low-energy intake is interpreted as a biologically meaningful consequence of the heightened hunger motivation. Furthermore, subjective hunger motivation was potentiated by stress when energy intake in the preceding hours was low. The latter result may be due to increased emotional reactions and/or an augmentation of deprivation-induced physiological changes by noise-induced emotional stress.

Adult↗

PubMed1984

Real time mathematical analysis of instantaneous respiratory signals at the bedside by a multiprocessor system (PAMS).

The authors address the following problems: How to turn a mass spectrometer, or a set of individual gas sensors, into a real and useful medical instrument? In other words, how to transform the instantaneous gas composition signals into meaningful physiological variables? The parameters that can be computed breath by breath from the real time processing of gas concentration signals, combined with flow and pressure signals at the mouth are first described. Particularly, we point out the theoretical and practical importance of alveolo-capillary gas exchange parameters, as opposed to gas exchange parameters estimated at the mouth level: A-c exchange parameters are a more sensitive and more specific indicator of any physiological change and they are less sensitive to breath by breath fluctuations of ventilation. We discuss the clinical usefulness of breath by breath computations, as a more sensitive way to monitor the patient as well as the anesthesia circuit, and to generate all the information required for on line analysis of functional tests. We describe a system for the real time processing of the respiratory signals. Based on three microprocessors it takes over the calibration, the offset correction of each signal ... It also corrects for the dynamics of each sensor and resynchronizes all the signals. It computes breath by breath more than 50 physiological variables that can be either recorded analogically, either printed, either acquired by a general monitoring system of the patient, which then combines respiratory data with other physiological. therapeutical and medical data from the patient.

Mass Spectrometry↗

PubMed2005

Early endotoxin-mediated haemostatic and inflammatory responses in the clopidogrel-treated pig.

We have previously shown that the thrombin inhibiting agent melagatran markedly prolongs aPTT and counteracts creatinine increase in endotoxemic pigs. Against this background the effects of the platelet-inhibiting agent, clopidogrel on basic haemostatic, inflammatory and physiological variables were evaluated during porcine endotoxemia. Clopidogrel (10 mg/kg) or saline was randomly injected i.v. 30 min before start of a 6-h continuous infusion of endotoxin in 12 anaesthetised pigs. Another three pigs were given clopidogrel but not endotoxin. Clopidogrel did not affect physiological variables, formation of activated platelet microparticles, PK, aPTT, platelet count, plasma fibrinogen, TNF-alpha, or IL-6 during porcine endotoxemia. Although renal function, as evaluated by creatinine clearance (CLcr) deteriorated significantly (P = 0.01) in the saline-endotoxin, but not in the clopidogrel-endotoxin group, there was no significant difference between the saline-endotoxin and the clopidogrel-endotoxin groups. Renal biopsies were marked with a FITC-labelled chicken anti-fibrinogen antibody detecting fibrinogen and platelet bound fibrinogen, as a marker of porcine platelet activation, and examined by light microscopy. Evaluation of these immunohistochemical slides did not indicate that clopidogrel, significantly reduced the amount of intrarenal fibrin or fibrinogen depositions. Besides a trend to preserve renal function, clopidogrel did not affect haemodynamics or the coagulatory and inflammatory responses in porcine endotoxemia.

Animals↗

PubMed1987

Local cerebral glucose utilization and local cerebral blood flow in conscious rats after administration of flunarizine.

The effects of the calcium entry blocker flunarizine on physiologic variables, local cerebral blood flow (LCBF) and local cerebral glucose utilization (LCGU) were investigated. LCBF and LCGU were determined in 37 anatomically discrete brain regions in lightly restrained, conscious rats, using the quantitative, autoradiographic 14C-iodoantipyrine and 14C-2-deoxyglucose techniques. While 5 mg/kg flunarizine given i.v. did not change any of the measured physiologic variables, flunarizine increased LCBF in nearly all gray matter structures compared with saline-treated controls. LCGU was not changed compared to controls. In control as well as in flunarizine-treated rats coupling between LCGU and LCBF was tight. The ratio of LCBF/LCGU was increased after treatment with flunarizine. The data suggest that under normal physiological conditions the calcium entry blocker flunarizine does not change neuronal activity, but exerts primarily a cerebral vasodilating action.

Animals↗

PubMed2006

Bradykinin B2 receptor antagonism with LF 18-1505T reduces brain edema and improves neurological outcome after closed head trauma in rats.

BACKGROUND: We evaluated the effect of LF 18-1505T, a novel nonpeptide bradykinin type-2 receptor antagonist, on brain edema and neurologic severity score (NSS) after closed head trauma (CHT). METHODS: There were 132 rats anesthetized and assigned for sham or CHT; infusion of saline or LF 18-1505T (0.3, 1, 3, 10, or 30 microg x kg x min); and determination of neurologic outcome (brain water content and NSS) or physiologic variables (blood pressure, glucose concentration, etc.). RESULTS: Post-CHT brain water content was less with LF 18-1505T doses of 3 and 10 microg x kg x min (80.1 +/- 3.8 through 81.6 +/- 2.6%, mean +/- SD) than in the untreated group (84.6 +/- 1.9%, p < 0.01). Post-CHT NSS improved with doses of 3, 10, and 30 microg x kg x min (median, 7; range, 0-12 through median, 10; range, 8-18) as compared with that in the untreated group (median, 17; range, 14-23; p < 0.05). LF 18-1505T with or without CHT did not significantly alter physiologic variables. CONCLUSIONS: LF 18-1505T decreased brain edema and improved neurologic status after CTH in rats without significantly altering physiologic values.

Animals↗

PubMed1991

Physiological effects of kangaroo care in very small preterm infants.

Kangaroo care for preterm infants has great benefits for the parents and for the parent-infant bonding process. A clinical observational study was conducted in which several physiological variables were collected, including among others transcutaneous oxygen pressure, heart rate, respiratory rate, occurrence of apneic attacks, breathing pattern (studied with power spectrum analysis), behavioral states and rectal temperature, during kangaroo care in small preterm infants. Kangaroo-care did not significantly affect any of these physiological variables comparing the period of 1 h before, 1 h during and 1 h after kangaroo care. We conclude that kangaroo care is a safe method, even for very small nonstabilized preterm infants.

Blood Gas Monitoring, Transcutaneous↗

PubMed2006

Neurodevelopmental outcome of infants with birth asphyxia treated with magnesium sulfate.

BACKGROUND: A neuroprotective effect of MgSO(4) has been shown in some animal models of perinatal hypoxic-ischemic brain damage. The aim of the present paper was to determine whether postnatal MgSO(4) infusion (250 mg/kg per day i.v. for 3 days, in combination with dopamine) is safe in infants with severe birth asphyxia, and also observe effects on neurodevelopmental outcome at 18 months. METHODS: Inclusion criteria were clinical history consistent with perinatal asphyxia; gestational age at least 37 weeks; 5 min Apgar score < or =6; failure to initiate spontaneous respiration within 10 min after birth; and symptoms of encephalopathy. On each day MgSO(4) was infused over 1 h in combination with dopamine (5 microg/kg per min). Changes in vital signs, clinical course of encephalopathy, laboratory variables, and adverse events were monitored. Infants were followed for 18 months. RESULTS: Thirty infants were studied. Mean birthweight was 2878 g; mean gestational age, 39.6 weeks, and median 5 min Apgar score, 3. All required endotracheal intubation for resuscitation. Median age at MgSO(4) initiation was 5 h. All infants had moderate or severe hypoxic-ischemic encephalopathy. Mean serum Mg(2+) concentration remained at least 1.3 mmol/L. MgSO(4) caused no change in physiological variables including mean arterial pressure. Two infants died as neonates, while six of 28 survivors had severe neurodevelopmental disability at 18 months; the remaining 22 had no neurodevelopmental disability. CONCLUSION: Postnatal infusion of MgSO(4) with dopamine caused no change in physiological variables. Deaths and severe sequelae were less frequent than in reported cases with the same grade of hypoxic-ischemic encephalopathy severity, and this treatment may improve neurodevelopmental outcome in infants with severe birth asphyxia.

Asphyxia Neonatorum↗

PubMed2001

Sleep pattern and daytime differences in the electromyographic activity and peripheral temperature.

For a long time, it has been said that most individuals sleep an average of 8 h. However, there are subjects that usually sleep less than 6 h (the ones placed under the label of short sleep pattern, SSP) and subjects that sleep more than 8 h (those classified by the long sleep pattern, LSP). Starting from this division, several studies have been carried out in order to establish possible differences in terms of psychological and physiological variables. This study is aimed at assessing the differences that might occur in electromyographic activity and temperature in long, medium and short sleep pattern subjects at two moments in the day. From a 300-subject sample, 17 long sleep pattern, nine medium sleep pattern and eight short sleep pattern subjects were selected. The physiological variables were assessed during a constant stimulation task in the morning (between 09.00 and 10.00 h) and in the evening (between 19.00 and 20.00 h). The inter-group analysis showed that the long sleep pattern and the short sleep pattern subjects differed in terms of electromyographic activity in the morning. This same analysis indicated that only long sleep pattern subjects showed changes in electromyographic activity over two measurements taken in the same day. The results point out that long sleep pattern subjects show more sensitivity towards changes, and that sensitivity is expressed in a different manner, depending on the time of the day.

Adult↗