Circadian rhythm of double (rate-pressure) product in healthy normotensive young subjects

The double product (DP), systolic blood pressure multiplied by heart rate, is a surrogate measure of myocardial oxygen demand and cardiac workload used increasingly today in medicine. The double product is more strongly correlated with left ventricular mass than the daily blood pressure mean. The purpose of this study was to describe the normative circadian pattern of the double product in healthy normotensive young adults. We studied 125 men and 75 women, 23.0+/-3.3 (mean +/- SD) years of age, without medical history of hypertension and 24h ambulatory systolic/diastolic blood pressure mean consistently below 135/85 mm Hg. Subjects underwent ambulatory blood pressure monitoring at 30-minute intervals for 48 consecutive hours once each season of the year, yielding 930 protocol-correct blood pressure and heart rate time series. Subjects maintained their usual routine of diurnal activity and nocturnal sleep and avoided use of over-the-counter and other medication. Circadian rhythmicity in the double product was established by population multiple-component analysis. The double product rose rapidly from the lowest value, attained 3h before awaking from sleep at night, to a markedly elevated level at the commencement of morning activity. The double product was highest in the afternoon, roughly 7h after the commencement of diurnal activity. In both men and women, the shape of the high-amplitude circadian rhythm in the double product was best described by a complex model composed of three cosine curves having periods of 24h, 12h, and 6h. The 24h mean in the double product of 8092.51+/-42.76 (mean +/- SD) in men was significantly lower than that of 8353.17+/-37.48 in women (P < .001). The circadian double amplitude of the rhythm was statistically significantly greater (P < .001) in men (50% of the 24h mean) than women (44% of the 24h mean). The double product did not differ between seasons in women, but it did in men (P = .017) due to reduced heart rate in summer. The circadian pattern of large amplitude in the double product and its gender differences must be taken into account when using this variable to assess cardiac workload, risk of left ventricular hypertrophy, and efficiency of antihypertensive therapy.     

Effect of imidapril in dipper and nondipper hypertensive patients: comparison between morning and evening administration

The purpose of the study was to identify differences in the patterns of efficacy and duration of effects of imidapril administered at different times of the day (morning versus evening) in dipper and nondipper hypertensive patients. Twenty patients with untreated hypertension were classified into two groups: dippers (n = 9) and nondippers (n = 11). Imidapril (10 mg) was given at 07:00 or 18:00 for 4 weeks in a crossover fashion. Blood pressure (BP) and heart rate (HR) were monitored before and after morning and evening treatment every 30 min for 48h by ambulatory BP monitoring (ABPM). In dipper hypertension, the mean 48h BP was reduced with both doses. The decrease in the diurnal BP was stronger when the drug was administered in the evening than morning, but without significant difference. In nondipper hypertension, the systolic BP decreased at night with both doses, but the extent of the nocturnal reduction in systolic BP was greater after morning therapy. There were no significant differences in the decrease in BP during the day or night between the morning and evening administrations. When imidapril was administered in the morning, its serum concentration reached a maximum at 16:00, and when the drug was administered in the evening, it reached a maximum at 6:00. In dipper hypertension, the time taken for the blood concentration of imidapril to reach a maximum changed depending on its time of administration, and the time when the maximum antihypertensive effect of the drug appeared was different. In nondipper hypertension, decreases in the BP were confirmed at night regardless of the time of administration; this might be caused by angiotensin converting enzyme (ACE) inhibitors effectively blocking the BP from increasing by activating the parasympathetic nervous system. Therefore, when assessing the effectiveness of antihypertensive agents, factors such as the various patterns of BP before therapy and administration time must be considered.     

EFFECT OF IMIDAPRIL IN DIPPER AND NONDIPPER HYPERTENSIVE PATIENTS: COMPARISON BETWEEN MORNING AND EVENING ADMINISTRATION

The purpose of the study was to identify differences in the patterns of efficacy and duration of effects of imidapril administered at different times of the day (morning versus evening) in dipper and nondipper hypertensive patients. Twenty patients with untreated hypertension were classified into two groups: dippers (n = 9) and nondippers (n = 11). Imidapril (10 mg) was given at 07:00 or 18:00 for 4 weeks in a crossover fashion. Blood pressure (BP) and heart rate (HR) were monitored before and after morning and evening treatment every 30 min for 48h by ambulatory BP monitoring (ABPM). In dipper hypertension, the mean 48h BP was reduced with both doses. The decrease in the diurnal BP was stronger when the drug was administered in the evening than morning, but without significant difference. In nondipper hypertension, the systolic BP decreased at night with both doses, but the extent of the nocturnal reduction in systolic BP was greater after morning therapy. There were no significant differences in the decrease in BP during the day or night between the morning and evening administrations. When imidapril was administered in the morning, its serum concentration reached a maximum at 16:00, and when the drug was administered in the evening, it reached a maximum at 6:00. In dipper hypertension, the time taken for the blood concentration of imidapril to reach a maximum changed depending on its time of administration, and the time when the maximum antihypertensive effect of the drug appeared was different. In nondipper hypertension, decreases in the BP were confirmed at night regardless of the time of administration; this might be caused by angiotensin converting enzyme (ACE) inhibitors effectively blocking the BP from increasing by activating the parasympathetic nervous system. Therefore, when assessing the effectiveness of antihypertensive agents, factors such as the various patterns of BP before therapy and administration time must be considered. (Chronobiology International, 17(2), 209–219, 2000)     

CIRCADIAN RHYTHM OF DOUBLE (RATE-PRESSURE) PRODUCT IN HEALTHY NORMOTENSIVE YOUNG SUBJECTS

The double product (DP), systolic blood pressure multiplied by heart rate, is a surrogate measure of myocardial oxygen demand and cardiac workload used increasingly today in medicine. The double product is more strongly correlated with left ventricular mass than the daily blood pressure mean. The purpose of this study was to describe the normative circadian pattern of the double product in healthy normotensive young adults. We studied 125 men and 75 women, 23.0 ± 3.3 (mean ± SD) years of age, without medical history of hypertension and 24h ambulatory systolic/diastolic blood pressure mean consistently below 135/85 mm Hg. Subjects underwent ambulatory blood pressure monitoring at 30-minute intervals for 48 consecutive hours once each season of the year, yielding 930 protocol-correct blood pressure and heart rate time series. Subjects maintained their usual routine of diurnal activity and nocturnal sleep and avoided use of over-the-counter and other medication. Circadian rhythmicity in the double product was established by population multiple-component analysis. The double product rose rapidly from the lowest value, attained 3h before awaking from sleep at night, to a markedly elevated level at the commencement of morning activity. The double product was highest in the afternoon, roughly 7h after the commencement of diurnal activity. In both men and women, the shape of the highamplitude circadian rhythm in the double product was best described by a complex model composed of three cosine curves having periods of 24h, 12h, and 6h. The 24h mean in the double product of 8092.51 ±42.76 (mean ±SD) in men was significantly lower than that of 8353.17 ±37.48 in women (P <.001). The circadian double amplitude of the rhythm was statistically significantly greater (P <.001) in men (50% of the 24h mean) than women (44% of the 24h mean). The double product did not differ between seasons in women, but it did in men (P =.017) due to reduced heart rate in summer. The circadian pattern of large amplitude in the double product and its gender differences must be taken into account when using this variable to assess cardiac workload, risk of left ventricular hypertrophy, and efficiency of antihypertensive therapy. (Chronobiology International, 18(3), 475–489, 2001)     

Dose‐ And Administration Time‐Dependent Effects Of Nifedipine Gits On Ambulatory Blood Pressure In Hypertensive Subjects

Previous chronotherapy studies have shown that the circadian pattern of blood pressure (BP) remains unchanged after either morning or evening dosing of several calcium channel blockers (CCB), including amlodipine, isradipine, verapamil, nitrendipine, and cilnidipine. This trial investigated the antihypertensive efficacy and safety profile of the slow‐release, once‐a‐day nifedipine gastrointestinal therapeutic system (GITS) formulation administered at different times with reference to the rest‐activity cycle of each participant. We studied 80 diurnally active subjects (36 men and 44 women), 52.1±10.7 yrs of age, with grade 1–2 essential hypertension, who were randomly assigned to receive nifedipine GITS (30 mg/day) as a monotherapy for eight weeks, either upon awakening in the morning or at bedtime at night. Patients with uncontrolled BP were up‐titrated to a higher dose, 60 mg/day nifedipine GITS, for an additional eight weeks. BP was measured by ambulatory monitoring every 20 min during the day and every 30 min at night for 48 consecutive hours before and after therapy with either dose. The BP reduction after eight weeks of therapy with the lower dose of 30 mg/day was slightly, but not significantly, larger with bedtime dosing. The efficacy of 60 mg/day nifedipine GITS in non‐responders to the initial 30 mg/day dose was twice as great with bedtime as compared to morning dosing. Moreover, bedtime administration of nifedipine GITS reduced the incidence of edema as an adverse event by 91%, and the total number of all adverse events by 74% as compared to morning dosing (p=0.026). Independent of the time of day of administration, a single daily dose of 30 mg/day of nifedipine GITS provides full 24 h therapeutic coverage. The dose‐dependent increased efficacy and the markedly improved safety profile of bedtime as compared to morning administration of nifedipine GITS should be taken into account when prescribing this CCB in the treatment of essential hypertension.     

Dose- and administration time-dependent effects of nifedipine gits on ambulatory blood pressure in hypertensive subjects

Previous chronotherapy studies have shown that the circadian pattern of blood pressure (BP) remains unchanged after either morning or evening dosing of several calcium channel blockers (CCB), including amlodipine, isradipine, verapamil, nitrendipine, and cilnidipine. This trial investigated the antihypertensive efficacy and safety profile of the slow-release, once-a-day nifedipine gastrointestinal therapeutic system (GITS) formulation administered at different times with reference to the rest-activity cycle of each participant. We studied 80 diurnally active subjects (36 men and 44 women), 52.1±10.7 yrs of age, with grade 1-2 essential hypertension, who were randomly assigned to receive nifedipine GITS (30 mg/day) as a monotherapy for eight weeks, either upon awakening in the morning or at bedtime at night. Patients with uncontrolled BP were up-titrated to a higher dose, 60 mg/day nifedipine GITS, for an additional eight weeks. BP was measured by ambulatory monitoring every 20 min during the day and every 30 min at night for 48 consecutive hours before and after therapy with either dose. The BP reduction after eight weeks of therapy with the lower dose of 30 mg/day was slightly, but not significantly, larger with bedtime dosing. The efficacy of 60 mg/day nifedipine GITS in non-responders to the initial 30 mg/day dose was twice as great with bedtime as compared to morning dosing. Moreover, bedtime administration of nifedipine GITS reduced the incidence of edema as an adverse event by 91%, and the total number of all adverse events by 74% as compared to morning dosing (p=0.026). Independent of the time of day of administration, a single daily dose of 30 mg/day of nifedipine GITS provides full 24 h therapeutic coverage. The dose-dependent increased efficacy and the markedly improved safety profile of bedtime as compared to morning administration of nifedipine GITS should be taken into account when prescribing this CCB in the treatment of essential hypertension.     

Payroll data based description of working hours in the Danish regions

ABSTRACT

The aim was to describe the organization of working hours in the Danish regions according to sex, age and calendar year. Based on the Danish Working Hour Database (DWHD), individuals were classified according to schedules: Permanent day (57.8%), evening (1.7%), or night (1.2%); day/evening (22.0%); day/night (6.6%); evening/night (0.6%); and day/evening/night (10.2%). More men (9.1%) than women (5.9%) worked day/night, whereas more women (10.9%) than men (7.4%) worked day/evening/night. More young than older employees worked day/evening/night, and fewer worked permanent day or night. From 2008 to 2015 we observed a trend towards more employees working permanent day and fewer employees working other schedules. Altogether DWHD provides a strong tool in research on working hours.     

Circadian variations in the sweating mechanism.

Sweat rates and body temperatures of human subjects were measured at 0200, 1000, and 1800 h during a heat exposure of 90 min. The latent period of sweating was not significantly altered in the evening but significantly shortened during the night. Mean body temperature corresponding to the onset of sweating was nearer to the basal body temperature during the night, while during the day the difference between these two temperatures became larger. This phenomenon seems related to the circadian cycle of vasomotor adjustment, since during the night body conductance was higher than during the day and corresponded to a state of a vasodilatation similar to that observed at the onset of sweating. During the day, this situation was reversed. During steady state, the following changes were observed: sweating rate, night less than morning less than evening; skin temperatures, night less than morning less than evening; and rectal temperature increase, morning less than evening less than night. It is hypothesized that these changes are due to either different metabolic rates or an imbalance between heat gains and losses which preserve the circadian rhythm of the body temperature, even under thermal loads.     

Cathemerality and lunar periodicity of activity rhythms in owl monkeys of the Argentinian Chaco

Although most South American owl monkeys are mainly nocturnal, Aotus azarai azarai of the Argentinean Chaco regularly shows diurnal activity. In this study we examined the strong influence of moonlight on its diurnal and nocturnal activity, as well as the interaction of moonlight effects with other exogenous factors. We analyzed long-term automated activity recordings obtained with accelerometer collars from 7 owl monkeys during 2003 and 2004. Our data show marked lunar periodic and seasonal modulations of the owl monkeys' activity pattern. On full moon days they were active throughout the whole night and displayed reduced activity during the day. With a new moon, activity decreased during the dark portion of the night, peaked during dawn and dusk and extended over the bright morning hours. Waxing and waning moons induced a significant increase in activity during the first and the second half of the night, respectively. During the cold winter months the monkeys displayed twice as much activity throughout the warmer bright part of the day than during the rest of the year. These findings indicate that A. a. azarai is mainly a dark-active species, but is still able to shift a considerable portion of activity into the bright part of the day if unfavourable lighting and/or temperature conditions prevail during the night.     

Collegiate rowing crew performance varies by morningness-eveningness

During adolescence and early adulthood, most humans are predisposed developmentally, both biologically and socially, toward evening/night activity. The morningness-eveningness (M-E) tendency to be an evening-preferring (E-type) rather than a morning-preferring (M-type) or intermediate/neither (N-type) "chronotype" may affect athletic performance at various times of day. This study evaluated M-E effects on rowing performance of an intact, experienced, university club crew with near-daily early morning (0500-0700 hours) and late afternoon (1630-1800 hours) training schedules. The hypothesis tested was that chronotype would modify circadian effects during morning and afternoon performances. Eight men and eight women (mean age 19.6 +/- 1.5 years) were tested in a randomized, counterbalanced design. A standard qualifying 2000-m ergometer rowing sprint and a nonroutine standing broad jump task were measured during early morning and late afternoon, separated by 3 days of rest. Each subject's chronotype was determined using two standard self-rating M-E scales, resulting in eight E-type (three women/five men), four M-type (two women/two men), and four N-type (three women/one man) subjects. The rowing results show that E-type and N-type subjects did not differ between morning and afternoon rowing performances, whereas M-type subjects rowed significantly faster in the morning. In contrast, the standing broad jump showed no consistent time-of-day or chronotype effect. These findings suggest that basic performance timing in young athletes is determined to some extent by naturally occurring M-E predispositions. Further, modification of time-of-day influences may be possible by routine practice at the same time each day, as was suggested here by the absence of evening superiority in performances. Understanding their personal M-E tendencies could allow young athletes to arrange training schedules at specific times of day to help counteract any natural circadian influences that might work against their performance.     

叶斑病对白桦树干液流的影响

应用热扩散法,对白桦树干液流进行连续两个生长旺期测定。与健康白桦相比,患叶斑病的白桦树干液流格局发生明显改变。在晴天树干液流密度日变化由单峰曲线转变为双峰曲线,或单峰曲线峰值较光合有效辐射峰值显著提前或推后;液流密度峰值及全天均值远远低于同期的健康白桦,且晚上及凌晨输水比例明显升高,表明晚上主要靠根压输送水分,维持光合作用必需原料及生长所需的矿物质;并且此时树干液流密度变化受外界环境因子的决定比重减小或根本无相关显著的环境因子。叶感病白桦树干液流具有以上特点,是因为具有较强的蒸腾生理调控力,以适应叶部病害而求得生存。     

Morning preference in onset of symptomatic third-degree atrioventricular heart block

The aim of this study was to examine 24h patterning in the symptoms indicative of third-degree atrio-ventricular (AV) heart block. We found a total of 227 cases (126 men and 101 women) of third-degree AV block that had been diagnosed by the Emergency Medical Department of the St. Anna Hospital in Ferrara, Italy between 1990 and 2001. Determination of the hour of onset of symptomatic third-degree AV block, however, was possible and listed in the records of only 161 or 70.9% of the cases (92 men and 69 women). The onset time of every event was categorized into one of four 6h spans of the 24h: night (00:00-05:59h), morning (06:00-11:59h), afternoon (12:00-17:59h), and evening (18:00-23:59h). The onset of the symptoms of third-degree AV block in the sample of 161 cases was significantly greater in the morning between 06:00 and 11:59h than any other 6h span of the day and night (chi2-test; p < 0.001). The same phenomenon was substantiated in the subgroup of the 92 males (chi2; p < 0.0001), although it could not be detected for the smaller subgroup of 69 women. The 24h pattern, with morning preference, in the onset of symptomatic third-degree AV block is similar to the one in sudden cardiac death and cardiogenic cardiac arrest. The etiology of the 24h pattern in symptomatic AV block is unknown; it may be an expression of intrinsic biological rhythmicity within the heart tissue or its control system, and/or the timing of environmental triggers resulting in coronary ischemia.     

Daily variation in body core temperature using radio-telemetry in aluminium industry shift-workers

The aim of this study was to investigate the diurnal variation in core temperature in aluminium shift-workers exposed to hot ambient conditions. Core temperature was continuously recorded via an ingestible radio-telemetry thermistor in 29 shift-workers. Data from the morning, afternoon and night shifts were aggregated for each participant to obtain 24-h recordings during work duties. Complete data were obtained from 10 participants. Results showed that body core temperatures recorded in the afternoon (from 12:00 h to 20:00 h) were significantly higher (P<0.05) than in the late evening, night and early morning (from 21:00 h to 08:00 h). In addition, core temperature displayed a circadian variation with a mesor of 37.45 (±0.19) °C, an amplitude of 0.23 (±0.12) °C and an acrophase at 16:36 h (±3:37 h). The peak values of core temperature recorded at each hour of the day on the work site followed the same pattern with an acrophase in the early afternoon. In summary, our data showed that shift-workers present higher core temperatures in the afternoon than in the morning or during the night. In addition, it was not the work duration but the hour-of-day that triggered the variation in core temperature. This result partly explains previous observations that workers under heat stress have a higher probability of heat illness during daytime shifts than during the night shift, and suggests that special care should be given to the afternoon shift and to the end of the morning shift.     

Study of sleep of shift workers with alternating schedules: adaptation and recovery in case of rapid shift rotation (3-4 days) (author's transl)

An electroencephalographic study of the sleep of shift workers (3 x 8) was performed in a French oil refinery. The recordings of diurnal sleep showed: a severe disorganization of the first day sleep (very short duration, decrease of PS and SWS in absolute amount); a trend towards better sleep characteristics (duration, PS and SWS amount) through the day-sleep period. Recovery night sleep appeared different when following curtailed night sleep (morning shift) and when following curtailed day sleep (night shift). Nocturnal sleep following immediately the diurnal sleep shows only partly the characteristics of a real recovery. Thus there seems to be a beginning adaptation to schedule reversal. This result supports a rapid shift alternation (3-4 days) which restrains both the cumulated sleep deficit and the adaptation to schedule reversal.     

Diurnal variation of tension-type headache intensity and exacerbation: An investigation using computerized ecological momentary assessment

ABSTRACT: BackgroundsTension-type headache is a common psychosomatic disease. However, diurnal variation of headache is yet to be clarified, perhaps due to the lack of an appropriate method to investigate it. Like other painful diseases, it would be helpful to know if there is diurnal variation in tension-type headaches, both for managing headaches and understanding their pathophysiology. The aim of this study was to determine if there is diurnal variation in the intensity and exacerbation of tension-type headache. METHODS: Patients (N = 31) with tension-type headache recorded for one week their momentary headache intensity several times a day and their acute headache exacerbations using a watch-type computer as an electronic diary (computerized ecological momentary assessment). Multilevel modeling was used to test the effects of time of day on momentary headache intensity and on the occurrence of acute exacerbations. RESULTS: A significant diurnal variation in momentary headache intensity was shown (P = 0.0005), with the weakest headaches in the morning and a peak in the late afternoon. A between-individual difference in the diurnal pattern was suggested. On-demand medication use was associated with a different diurnal pattern (P = 0.025), suggesting that headache intensity decreases earlier in the evening in subjects who used on-demand medication, while headache subtype, prophylactic medication use, and sex were not associated with the difference. The occurrence of acute headache exacerbation also showed a significant diurnal variation, with a peak after noon (P = 0.0015). CONCLUSIONS: Tension-type headache was shown to have a significant diurnal variation. The relation to pathophysiology and psychosocial aspects needs to be further explored.     

Diurnal variations in intervertebral disc height affect spine flexibility,intradiscal pressure and contact compressive forces in the facet joints

Diurnal changes of intervertebral disc height are caused by high compressive loading during the day, which expulses fluid from the disc, and by osmotic pressure, which imbibes fluid into the disc at low loading. The aim of the present study was to determine the magnitude of diurnal changes in spine flexibility, intradiscal pressures and contact forces in the facet joints. A validated osseoligamentous finite element model of the lumbar spine was used to determine these quantities for morning and evening situations. Disc height varied by 10% for these two situations. Spine flexibility and facet joint forces were markedly higher in the evening than in the morning. Intradiscal pressures were higher in the morning than in the evening. The different spine flexibilities in the morning and evening should be taken into account during kinematical measurements. Predicted facet joint forces may be used for the designing and pre-clinical testing of artificial facet joint replacements.     

The validity of the temporal parameters of the daily rhythm of melatonin levels as an indicator of morningness

The present study tested the assumption that the temporal parameters of melatonin synthesis indicate the individual circadian phase position better than the minimum of rectal temperature. Thirty-four men and 17 women (16-32 yr, 14 morning, 14 neither, 23 evening types) completed a constant routine (24-26 h bedrest, <30 lux, 18-20 degrees C, hourly isocaloric diet). Salivary melatonin level was determined hourly, rectal temperature and heart rate were continuously recorded throughout. The minima of rectal temperature and heart rate as well as the temporal parameters of melatonin synthesis occurred earlier in morning than in evening types and were significantly related to the subjective circadian phase as determined by the morningness-eveningness questionnaire. The level of significance and the resolving power was greater for the melatonin parameters and for the minimum of heart rate than for the minimum of rectal temperature. The temporal differences between the opposite diurnal types were larger and the correlation coefficients with morningness were higher in men than in women. The temporal parameters of melatonin synthesis are valid indicators of the individual circadian phase. As morningness is closely related to the ability to cope with shiftwork, the determination of the melatonin profile might be a valuable element of the criteria when assigning a person to shiftwork.     

Shifts of the hormonal rhythms of melatonin and cortisol after a 4 h bright‐light pulse in different diurnal types

If applied during corresponding times of the individual melatonin profiles, bright light shifts the circadian phase equally, irrespective of diurnal type. We examined 32 young men: 10 morning types, 11 evening types, and 11 with no predisposition; 16 with high and 16 with low melatonin production. Each completed a 40 h session that included two consecutive nights during which the participants remained, apart from two short breaks during the second day, in bed under an illumination level of 30 lux. A 4 h bright light pulse was applied just after the expected individual melatonin onset the first night to cause a delay of the hormonal profile the second night. Salivary levels of melatonin and cortisol were determined hourly. Melatonin was delayed by 108 min, and cortisol offset and onset by 47 and 110 min, respectively. The cortisol quiescent period (start and end of the quiescent period being defined by the decrease below and the increase above 60% of the average cortisol production between 18:00 and 09:00 h) was prolonged. In contrast to the other subgroups, the delay of melatonin synthesis was about 0.5 h shorter in morning types, and their cortisol quiescent period was shortened. The present study leads to the hypothesis that, despite individually scheduled light exposure, morning types are potentially disadvantaged due to elevated cortisol levels, if persisting, in career night workers.     

Olfactory discrimination and transient mood change in young men and women: variation by season, mood state, and time of day

Odor performance varies by clinical state and gender, though little is known about its variation by season or time of day. Many odors, including lavender, induce transient mood changes. This study explored discrimination differences between various lavender oil blends and their effects on transient mood in the morning and evening in depressed and nondepressed adults. We also determined seasonal influences on these measures. A total of 169 subjects, 98 women and 71 men (mean age +/- SD, 19.3 +/- 1.6 y) participated, with different subjects studied at different times of the year. The Beck Depression Inventory (BDI) classified subjects as depressed (score > or =10; N= 57) or nondepressed (score <10; N= 112). In the discrimination test, subjects compared pairs of two different lavender oil blends or a control. Transient change in mood was assessed by the Profile of Mood States (POMS) after each trial of five lavender blends interspersed by three control odors. Tests were conducted in the morning (08:00-10:00 h) and evening (18:00-20:00h). In all subjects, discrimination was significantly better for some odor pairs than for others, thus demonstrating test specificity. Discrimination was better overall in the fall than winter/spring and better in depressed than nondepressed subjects for specific odor pairs. No significant gender or time-of-day differences in discriminability were detected. There were, however, significant group differences in transient mood profiles. Current depressed state affected mood response, with lavender increasing anger in depressed subjects only. In addition, depressed subjects and men, whether or not depressed, exhibited diurnal mood variation, with better mood in the evening; the former group also showed more evening energy. All subjects were more confused in the morning than evening. Season also affected transient mood; winter/spring-tested subjects reported more vigor than fall-tested subjects. In addition, summer-tested subjects showed more tension in the morning, whereas fall-tested subjects showed the opposite pattern in the evening. In all subjects, lavender increased fatigue, tension, confusion, and total mood disturbance, and it decreased vigor. The study showed that both chronobiological (seasonal and time-of-day) and clinical factors modify discrimination and mood response to odors. Brief lavender odor presentation may serve as a nonphotic method for altering mood in young depressed and nondepressed adults particularly during the fall, a time of heightened discriminability.     

Effects of dose and timing of calcium supplementation on bone resorption in early menopausal women.

Bone resorption follows a circadian rhythm that peaks at night, reflecting the circadian rhythm of serum parathyroid hormone. Our previous studies in early postmenopausal women have established that 1000 mg of calcium given at 9 p. m. reduced bone resorption markers overnight, but not during the day. In contrast, 1000 mg given as a divided dose (500 mg doses at 9 a. m. and 9 p. m. each) reduced bone resorption markers during the day, but not during the night. We have now evaluated the effect of 1500 mg of calcium given as a divided dose of 500 mg in the morning and 1000 mg in the evening on bone resorption. We studied 26 healthy women (median age 56 years) whose menopause was less than five years before. On two days, urine was collected from 9 a. m. to 9 p. m. (day collection), and from 9 p. m. to 9 a. m. (night collection); a further fasting (spot) urine sample was obtained at 9 a. m. at the end of the night collection. On the second day, 500 mg of calcium in the carbonate form was taken at 9 a. m. (at the start of the collection) and a further 1000 mg at 9 p. m. (at the start of the second night collection). Calcium supplementation decreased urinary deoxypyridinoline (DPyr/Cr) during the day (p = 0.08) and night (p < 0.05), as well as urinary pyridinoline (Pyr/Cr) both by day (p < 0.05) and night (p < 0.001). There were also decreases in urine hydroxyproline. We conclude that the acute administration of 500 mg of calcium in the morning and 1000 mg in the evening to early postmenopausal women suppresses bone resorption markers during both the day and night.