Daily hunger sensation monitoring as a tool for investigating human circadian synchronization.

This study investigates within-day hunger sensation (HS) variability in Clinically Healthy Subjects Adapted to Living in Antarctica (CHSALA), as compared to their coeval subjects living in their mother country. The aim is to detect how the orectic stimulus behaves in those environmental conditions and occupational schemes, in order to investigate the individual synchronization to sleep-wake alternation and meal time schedule. HS was estimated via a self-rating score of its intensity on a Visual Analog Scale, repeating the subjective perception every 30 min, unless sleeping. The individual HS time-qualified scores (orexigram) were analyzed according to conventional and chronobiological procedures. The orexigrams of the CHSALA were seen to show a more cadenced intermittence during the diurnal part of the day, strictly related to the meal timing, and a preserved circadian rhythm as well. In addition, these orexigrams were resolved in a spectrum of harmonic components which indicated a subsidiary number of ultradian formants. These findings are convincing evidence that the individual orexigram may be used to investigate whether or not a single subject is synchronized to sleep-wake cycle, meal time schedule and socio-occupational routines, instead of using more complex and expensive techniques, involving automated equipments and biohumoral assays.

Age-related trend for blood pressure circadian rhythm in normotensive healthy subjects: estimates provided by the clinospectror method.

The present study investigates how blood pressure (BP) circadian rhythm (CR) changes in its rhythmic properties as a function of chronological age in normotensive healthy subjects (NHS). The age-related trend for BP CR was investigated via the Clinospectror method, a periodic-linear analysis of regression for rhythmic parameters. The study was performed on 437 NHS (219 males and 218 females, ranging in age from 1 year to 102 years), who were monitored in their 24-h BP via a noninvasive automated recorder. An age-related trend was detected for the three properties of BP CR, i.e., mesor (M), amplitude (A) and acrophase (cent). Such a trend was positive for M and A, and negative for cent. According to the clinospectrometric formula, the BP CR can be classified as a "dianaclinous rhythm", i.e., a rhythm which increases in its oscillatory level and extent with advancing years. The documented age-related trend for the rhythmic properties suggests that the biological clock which regulates the BP CR in human beings undergoes a resetting of its mechanisms of tonic, amplitude and phasic modulation as a function of chronological age. The readjustment of the pressure clock may be regarded as one of the physiological features which characterize the aging process in human beings.

Preserved blood pressure and heart rate circadian rhythm in early stage Alzheimer's disease.

BACKGROUND: This study investigated the blood pressure (BP) values over the day-night period in 11 noninstitutionalized patients affected by probable Alzheimer's disease (AD) in its early stage. The scientific aim was to detect whether the BP circadian rhythm (CR) was preserved, given the fact that CR disruption was observed in advanced or institutionalized AD patients. METHODS: The BP within-day values were gathered via noninvasive ambulatory monitoring. The BP time series were analyzed according to the chronobiological procedure, called Cosinor method with three harmonic components. RESULTS: The biometric analysis was able to document that BP changes over the 24-h scale in AD patients as a function of a significant CR. Such a preserved circadian regulation is, however, compromised in the second and third harmonic component, suggesting that the BP within-day variability is desynchronized by the environmental clues that act as synchronizers during the diurnal part of the day. CONCLUSIONS: The preservation of the BP CR in the early stage of AD suggests using such a finding as a clinical tool for confirming the recent onset of the disease. As a matter of fact, it is presumed that the disease is not evolved enough to reach the suprachiasmatic nuclei, wherein is located the BP circadian pacemaker. The abolition of the ultradian components is another precocious sign that, in turn, indicates early-stage AD patients to be particularly compromised in their synchronization to diurnal cues, such as social routines, meal timing schedule, psycho-physical activity, and occupational schemes.

Anxiety, depression, hunger and body composition: III. Their relationships in obese patients.

The present paper explores the relationships between anxiety, depression, hunger sensation and body composition in obese patients (OP). The aim is to detect whether or not there are abnormalities in these relationships in OP as compared to clinically healthy subjects (CHS). The study was performed on 22 CHS (2 M, 20 W; mean age = 24 +/- 2 years; mean body mass index = 21 +/- 2 kg/m2) and 48 OP (4 M, 44 W; mean age = 40 +/- 17 years; mean body mass index = 32 +/- 7 kg/m2). Anxiety and depression were found to be correlated, negatively, with the relative lean body mass, and, positively, with the fat body mass in OP but not in CHS. These findings corroborate the idea that anxiety and depression can reach an abnormal expression when obesity shows its worst loss in lean body mass and its highest expansion in adipocyte mass. As hunger sensation was found not to correlate with either anxiety or depression in OP, the opinion is expressed that the impairment of anxio-depressive integrity is a corollary of obesity rather than a primary affective disorder leading to obesity via an enhanced food intake.

Daily hunger sensation and body compartments: II. Their relationships in obese patients.

Hunger sensation (HS) is a signal whose levels change during the 24-h day. The daily mean level of HS was correlated with the human body compartments, as investigated by bioelectrical impedance analysis, to detect the relationship between the orectic perception and both the free fat mass (FFM) and the fat body mass (FBM) in 22 clinically healthy subjects (CHS) (2 M, 20 W, BMI: 18.5-24.0 kg/m2) and 48 obese patients (OP) (4 M, 44 W, BMI: 25.2-54.7 kg/m2). In CHS, the daily mean level of HS correlated positively with the FFM and negatively with the FBM. These correlations were not present in OP. This lack of relationships between HS and the body compartments where energy is maximally consumed (i.e., the FFM) and maximally stored (i.e., the FBM) indicates that the orectic response to energy expenditure and the orectic inhibition to fat accumulation are feedback mechanisms which are impaired in obesity.

Who are the non-dippers? A better definition via the blood pressure circadian rhythm.

OBJECTIVE: The non-dipping phenomenon (NDP) can be better interpreted when considering that blood pressure (BP) shows a within-day variability which is the expression of a circadian rhythm (CR). PATIENTS AND METHODS: The NDP was investigated at the light of the BP CR by analysing the ambulatory BP monitoring of 298 essential hypertensive patients (EHP), 84 secondary hypertensive patients (SHP), as well as 93 normotensive subjects (NS). According to the rhythmometric validation, the investigated subjects were defined "rhythmic" (R) or "non-rhythmic" (NR). RESULTS: The non-dippers (ND) were found among not only the EHP (14%) and SHP (27%) but also the NS (16%). The percentages of R ND were 9%, 4% and 20%, respectively in EHP, SHP and NS. The R ND were characterized by a nocturnal phase-shift (100% in NS), associated with an amplitude increase (50% in EHP) or a mesor increase (50% in EHP; 100% in SHP) in BP CR. The NR ND were characterized by an amplitude almost negligible (100% in NS) associated with a mesor increase (100% in EHP; 100% in SHP). CONCLUSIONS: The detection of a NDP associated with a rhythmicity suggests that the criterion with which the ND are identified cannot be used for making inferences on the BP CR in HP or NS. The rhythmic characteristics in ND suggest that the rhythmometric analysis is fundamental for identifying the abnormal time structure of BP 24-h values in the presence of the NDP.

Daily hunger sensation and body composition: I. Their relationships in clinically healthy subjects.

The human hunger sensation (HS) is a perceptive signal characterized by day-night variability (DNV). This pattern was investigated with respect to its relations with the body compartments in 22 clinically healthy subjects (CHS, 11 males and 11 females, mean age: 24 +/- 2.5 years, mean BMI: 21 +/- 1.7). The DNV was investigated by means of conventional descriptive statistics and the single cosinor method (SCM). Both procedures were applied to the orexigram, i.e., the 24-h profile of the orectic stimulus (OS) provided by each subject, who self-rated his/her HS (from 1 to 10 hunger units) every half hour. Body composition was investigated by Bioelectrical Impedance Analysis (BIA) on the day when the orexigrams were compiled. It was found that the daily HS level correlates positively with the Free Fat Body Mass (FFBM) and negatively with the Fat Body Mass (FBM). These opposite relations indicate that HS is stimulated by the needs of the FFBM, and inhibited by expansion of the FBM, and provide further evidence of the existence of an "adipostat" anorectic mechanism.

'Minimal-change hypertensive retinopathy' and 'arterial pre-hypertension', illustrated via ambulatory blood-pressure monitoring in putatively normotensive subjects.

PURPOSE: To investigate the 24 h blood-pressure (BP) pattern in subjects who were found to show some incipient signs of hypertensive retinopathy but had been diagnosed as normotensives by means of casual sphygmomanometry. METHODS: Non-invasive ambulatory BP monitoring was performed in 25 caucasian subjects (16 M, 9 F; mean age 46 +/- 16 years) showing this type of retinal problem. A comparable number of controlled normotensive Caucasian subjects (15 M, 10 F; mean age: 48 +/- 15 years) without funduscopic signs of hypertensive retinopathy were investigated as a reference group. A series of BP tests over time was analysed by means of conventional biometry and chronobiological methods. RESULTS: The biometric estimates suggest that the investigated subjects with incipient hypertensive retinopathy, although characterized by BP values below 140/90 mmHg, show a significantly higher daily systolic BP. The increase, however, is within WHO reference limits and is not associated with the abolition of the circadian BP rhythm. CONCLUSIONS: The results suggest that the initial signs of hypertensive retinopathy may appear before BP elevation above WHO reference limits occurs. Because of this, it can be assumed that there is such a condition as 'minimal-change hypertensive retinopathy' associated with a haemodynamic picture of 'arterial pre-hypertension'.

Ambulatory blood pressure monitoring in clinically healthy subjects adapted to living in Antarctica.

This study investigates 24-h blood pressure (BP) and heart rate (HR) values in clinically healthy subjects adapted to living in Antarctica, as compared to their coeval subjects living in their home country. Its aim is to detect how cardiovascular rhythms behave in those environmental conditions and occupational cues. The 24-h BP and HR values were measured via a noninvasive ambulatory monitor, and statistically analyzed via conventional and chronobiological procedures. The normotensive subjects living in Antarctica were seen to show significant changes in the daily mean level of systolic BP (increase) and HR (decrease) as compared to their controls. In addition, they were seen to show the BP and HR circadian rhythms to be perfectly synchronized to the 24-h cycle, despite the permanent solar light, as an effect imposed by the routines of their local lifestyle. The observed changes reflect a tonic modulation of the BP and HR circadian rhythms which allows the cardiovascular apparatus to adapt itself without imposing an extra load on its function.

[Who are the "non-dippers": an insight from the ambulatory monitoring of arterial pressure in heart transplant patients]. / Chi sono i "non-dipper": un approfondimento dal monitoraggio ambulatorio della pressione arteriosa nei cardiotrapiantati.

This study was performed in order to define who are the "non-dippers", knowing that their present definition does not imply any explanation about the mechanisms. The investigation was performed on 34 heart transplanted patients, 28 males (mean age 52 +/- 11 years) and 6 women (mean age 35 +/- 14 years), knowing that the "non-dippers" were described as the hypertensives who are devoid of the expected nocturnal fall in blood pressure (BP). The "non-dipping" phenomenon was investigated by exploring the BP 24-h pattern via ambulatory non-invasive BP monitoring, and by applying the rhythmometric analysis for quantifying the BP circadian rhythm. The study provided evidence that the "non-dippers" can be found among the hypertensives as well as the normotensives, suggesting that high BP is not a necessary condition for the "non-dipping" phenomenon, and vice versa. Both the normotensive and hypertensive "non-dippers" were seen to show stereotypic changes in BP circadian rhythm. There are normotensive and hypertensive "non-dippers" with or without the BP circadian rhythm. The "rhythmic non-dippers" show a BP circadian rhythm which is inverted in phase or demodulated in amplitude. The "non-dippers" are, thus, a heterogeneous category.

[Minimal lesion hypertensive retinopathy and arterial pre-hypertension: evidence of arterial pressure monitoring in presumed normotensive subjects at zero risk]. / Retinopatia tensiva a lesioni minime e pre-ipertensione arteriosa: evidenze dal monitoraggio della pressione arteriosa in soggetti reputati normotesi a rischio zero.

The present study investigates the blood pressure (BP) 24 h pattern in 25 subjects who were found to show some incipient signs of hypertensive retinopathy, although they were diagnosed as normotensive by means of casual sphygmomanometry. BP was controlled by means of non invasive ambulatory monitoring. A comparable number of normotensive subjects without fundoscopic signs of hypertensive retinopathy was investigated as a control group. BP times series were analyzed by means of conventional and rhythmometric biometry. The biometric estimates suggest that the subjects with incipient hypertensive retinopathy show a significantly higher level of daily systolic BP even though their BP values remain below the reference limits. This finding suggests that the hypertensive retinopathy may exist in a non-zero stage characterizable as minimal change tensive retinopathy. This retinal picture occurs in subjects who show a pre-hypertensive stage in their BP 24 h pattern.

[The role and chronobiometric study of ambulatory arterial pressure monitoring in hypertensive patients with a recent cerebral ischemia episode]. / Ruolo e studio cronobiometrico del monitoraggio ambulatoriale della pressione arteriosa in pazienti ipertesi con recente episodio ischemico cerebrale.

Essential hypertensive patients with a history of recent TIA syndrome were investigated by ambulatory blood pressure monitoring (ABPM). The aim of this trial was to verify the presence of false normotensive patients in order to optimize the secondary prevention of hypertensive cerebrovascular damage (ischemic or hemorrhagic stroke). This study was carried out on 51 patients (26 M and 25 F, mean age = 58 +/- 14 yrs) and 225 clinically healthy control subjects (113 M and 112 F, mean age = 55 +/- 12 yrs), who underwent an ABPM. The BP time series were analyzed by chronobiometric procedures. The comparison of the individual BP within-day values to the reference limit revealed a highly significant proportion of these patients (90%) whose hypertension was not well controlled. Their BP series showed supranormal values ranging from 39% to 56% of all the readings, with a pressure excess ranging from 8.35 h to 11.34 h. The high incidence of not adequately treated patients with a history of recent TIA syndrome confirms that their hypertension should be controlled by means of the ABPM. These results suggest that the chronomodulation of the antihypertensive treatment might be the better management of BP regimen in these patients for the secondary prevention of cerebrovascular damage.

Circadian rhythms in human body composition.

The study investigates how the human body composition (BC) changes as a function of the day-night cycle. The BC was investigated using bioelectrical impedance analysis (BIA) of 10 clinically healthy subjects (CHS), monitored in supine position (readings at 2-h intervals), avoiding mealtimes, dietary abuses, and bladder and intestinal retention. Time series data were analyzed for their temporal characteristics and circadian rhythm (CR). All the variables of BC (lean body mass, fat body mass, body cell mass, total body water, intracellular and extracellular body water, sodium and potassium exchangeable pool) showed a within-day variability with nighttime crests. Such an oscillatory synchronism corroborates the hypothesis that the rest time plays a fundamental role, via its anabolic effects, in conferring the nocturnal phase to the CR of the human BC.

[Hypertensive cardiac damage in heart transplantation. A noninvasive monitoring study of arterial pressure]. / Il danno ipertensivo cardiaco nel trapianto di cuore. Studio con monitoraggio non invasivo della pressione arteriosa.

This study is aimed at investigating the relationship between cardiac hypertrophy and blood pressure (BP) 24-h pattern in 34 heart transplanted patients (HTP), 9 out of them (26%) being considered as normotensives, the other ones (74%) being regarded as hypertensives under adequate treatment, via casual sphygmomanometry. The study is an attempt to explain the occurrence of at least one sign of hypertrophic cardiopathy in 20 cases (59%), hypothesizing the presence of false normotensives among the putative normotensives and presumably-cured hypertensives. The ambulatory BP monitoring was able to identify 7 hypertensives (78%) among the putative normotensives, and 17 not well-cured subjects (68%) among the presumably cured hypertensives. At least one sign of cardiac hypertrophy was found in 5 (50%) of the 10 true normotensives, who were all non-dipper, and in 15 (63%) of the 24 hypertensives. The 9 hypertensives without cardiac hypertrophy (37%) had developed hypertension very recently. These findings stress the role of the ambulatory BP monitoring as a diagnostic tool during the follow-up of HTP, in order to identify the false normotensives as well as the not well-treated hypertensives. This role can contribute to optimize the prophylaxis of hypertensive damage for the transplanted heart.

[Describing and interpreting systemic hypertension in heart transplantation with non-invasive arterial pressure monitoring]. / Descrivere e interpretare l'ipertensione sistemica nel trapianto di cuore alla luce del monitoraggio non invasivo della pressione arteriosa.

This investigation was performed in 34 heart transplanted patients (HTP), 28 males and 6 females, mean age 49 +/- 13 years. The aim of the study was to detect hypertension in HTP by casual sphygmomanometry and non-invasive ambulatory blood pressure monitoring (ABPM). The evaluation of ABPM demonstrated that 71% out of the HTP was hypertensive because of some elevated blood pressure values scattered during the hours of the day and/or of the night. These hypertensives were found within the groups of normotensives as well as of hypertensives considered to be correctly treated. Fifty percent hypertensive HTP did not show the physiologic nocturnal decrease in blood pressure (non-dippers); 25% out of the non-dipper hypertensives showed absence of the blood pressure circadian rhythm, demonstrating that their hypertension was prevalently nocturnal and could not be detected by casual sphygmomanometry-The ABPM is recommended in clinical follow-up of HTP for a correct diagnosis of hypertension, which frequently complicates heart transplantation, and with the aim of avoiding hypertensive damage of the transplanted organ. The ABPM is useful for adjusting the antihypertensive therapy, in order to restore the blood pressure circadian rhythm.

[The Campodimele study: 24-hour blood pressure in rural life style subjects]. / Studio di Campodimele: la pressione arteriosa di 24 ore in soggetti con stile di vita rurale.

The present paper is aimed at investigating the daily blood pressure in subjects with a rural style of life with the purpose of detecting whether or not the blood pressure regimen is influenced as expected because of the stress less prominent in the non-urban areas. Control data were obtained by the study of age- and sex-matching subjects with a metropolitan style of life. The results indicate the blood pressure has a lower daily level in rural subjects as compared to urban subjects. The daily baric impact is also lower, suggesting that the blood pressure regimen is really less pronounced in those who live according to a rural style of life. Such a lower magnitude allows us to experimentally suggest that the rural life is concrete in protecting the hemodynamic system from the higher level of blood pressure which are observable in subjects who live according to a metropolitan style of life. Interestingly, the expected phase anticipation in blood pressure circadian rhythm of rural subjects was not detected, as the wake up time was not so anticipated to act as a synchronizer.