Rest-activity rhythm in breast cancer survivors: an update based on non-parametric indices

Recently we evaluated by actigraphy the rest-activity circadian rhythm (RAR) in breast cancer (BC) survivors at 5 years from primary diagnosis, as well as in a control group with similar age and body mass index (BMI). RAR, analyzed by Cosinor method, resulted significantly different in BC survivors compared to healthy subjects: BC survivors showed lower values of MESOR and Amplitude (A), while acrophase (φ) was similar in the two groups. Now, using non-parametric methods we have detected Interdaily Stability (IS), Intradaily Variability (IV), nocturnal activity (L5), and daily activity (M10) on the same sample of previous study: 15 BC survivors at 5 years from the primary diagnosis (mean age = 56.7 ± 6.6 yrs; mean BMI = 24.5 ± 3.8 Kg/m²) and 13 healthy controls (mean age = 54.4 ± 7.2 yrs; mean BMI = 25.2 ± 2.8 Kg/m²). The non-parametric indices showed that in BC-group IV was significantly higher than in Ctrl-group (0.86 vs. 0.65 a.u. in BC and Ctrl, respectively; p <.01), while L5 (11.27 vs. 34.41 a.c. in BC and Ctrl, respectively; p <.0001) and M10 (326.82 vs. 428.07 a.c. in BC and Ctrl, respectively; p <.01) were significantly lower compared to Ctrl-group. The data suggest that BC patients need constant clinical assessment of RAR characteristics along the years following the primary diagnosis. The analysis of RAR in all its components, parametric and non-parametric, is important to detect alterations in the sleep-wake cycle and can be useful for developing new strategies for health protection, such as structured and tailored physical activity programs, to improve circadian activity level in order to raise the quality of life in BC survivors.

Effect of chronotype on motor skills specific to soccer in adolescent players

Circadian rhythms influence daily behavior, psychological and physiological functions, as well as physical performance. Three chronotypes are distinguished according to the preferences people typically display for activity at certain times of day: Morning, Neither, and Evening types (M-, N- and E-types). The chronotype changes with age: eveningness tends to be stronger in youth and morningness in older age. The progressive shift toward eveningness during adolescence creates misalignment with morning society schedules and can lead to a deterioration in intellectual and physical performance. Soccer is one of the world's most popular sports practiced by adolescents and soccer workouts are usually held after school in the afternoon or evening. Performance in soccer is related to a host of factors, including physiological variables and motor skills that have a circadian variation. The aim of this study was to determine the effect of chronotype on motor skills specific to soccer, specifically whether agility, aerobic endurance, and explosive power differ among the three chronotypes in relation to the time of day. For this study 141 adolescent soccer players filled in the Morningness-Eveningness Questionnaire (MEQ) for the assessment of chronotype. A subsample of 75 subjects, subdivided in M-types (n= 25), E-types (n= 25), and N-types (n= 25), performed three tests (Sargent Jump Test - SJT, Illinois Agility Test - IAT, and 6-Minutes Run Test - 6MRT) at a morning and an evening training session (9:00 am and 6:00 pm). Mixed ANOVA was used to test the interactions between chronotypes, physical performance, and time. On all tests, better performance during the morning than the evening session was observed for the M-types (p< .05), whereas the E-types performed better in the evening than in the morning session (p< .05), and no differences in test performance were detected for the N-types. These findings underline the importance of a correct chronobiological approach to sports training. Scheduling training sessions according to an athlete's circadian preferences could be a valid strategy to enhance performance.

Effect of chronotype on academic achievement in a sample of Italian University students

Circadian rhythms play an important role in biological function; their expression differs across individuals; three chronotypes are distinguished: Morning- [MT], Evening- [ET], and Neither- [NT] type. MT achieve peak activation in the first part of the day and are generally more conscientious and achievement-oriented than ET, which reach their best during the second half of the day and express a higher intelligence. University class schedules can sometimes conflict with ET circadian preferences, compromising their academic performance compared with their MT classmates. Conversely, MT students, being more aligned with their daily schedule, might be more advantaged in their mental performance. The attitudes and performance of NT students are little considered. No studies to date have investigated academic achievement in relation to chronotype in an Italian student population. To fill this gap, this study examined the relationship between chronotype and academic performance in a population of Motor Science Faculty in Milan, differentiating achievement in theoretical and practical subjects by chronotype. The study population was 423 university students (290 males and 133 females) and categorized by chronotype according to Morningness-Eveningness Questionnaire (MEQ) scores. Student transcripts were reviewed to obtain exam grades on three practical and three theoretical subjects. The interaction between MEQ score or chronotypes and mean exam grade was evaluated using one-way ANOVA. The mean grades on the theoretical and practical exams were higher for the MT than for either the ET or the NT students. The NT students (24.8 ± 0.1) had lower mean grades for the theoretical subjects than either the MT (26.3 ± 0.4) or the ET (25.3 ± 0.2) students, while the ET (26.6 ± 0.2) performed worse than either the MT (27.8 ± 0.2) or the NT students (26.9 ± 0.1) on the practical exams. The same trend was observed for the total sample and when subdivided by sex. In the total sample, significant differences in theoretical and practical exam grades were noted between chronotypes: MT vs ET (p < .002, p < .0006) and MT vs NT (p < .04, p < .003). The differences between the males were significant for the theoretical (p < .006, MT vs NT, p < .002) and the practical subjects (MT vs ET p < .004, MT vs NT, p < .01), but no significant differences were noted between the females. Our findings indicate overall better academic achievement by the MT students, whereas the NT had lower exam grades for the theoretical subjects and the ET performed worse on the practical exams. We speculate that the higher intelligence expressed by the ET students might have helped them compensate the disadvantage on the theoretical but not on practical exams, in which the effect of misalignment between circadian preferences and university class schedule was more evident.

Rest-activity circadian rhythm and sleep quality in patients with binge eating disorder

Recent findings suggest that altered rest-activity circadian rhythms (RARs) are associated with a compromised health status. RARs abnormalities have been observed also in several pathological conditions, such as cardiovascular, neurological, and cancer diseases. Binge eating disorder (BED) is the most common eating disorder, with a prevalence of 3.5% in women and 2% in men. BED and its associate obesity and motor inactivity could induce RARs disruption and have negative consequences on health-related quality of life. However, the circadian RARs and sleep behavior in patients with BED has been so far assessed only by questionnaires. Therefore, the purpose of this study was to determine RARs and sleep parameters by actigraphy in patients with BED compared to a body mass index-matched control group (Ctrl). Sixteen participants (eight obese women with and eight obese women without BED diagnosis) were recruited to undergo 5-day monitoring period by actigraphy (MotionWatch 8®, CamNtech, Cambridge, UK) to evaluate RARs and sleep parameters. In order to determine the RARs, the actigraphic data were analyzed using the single cosinor method. The rhythmometric parameters of activity levels (MESOR, amplitude and acrophase) were then processed with the population mean cosinor. The Actiwatch Sleep Analysis Software (Cambridge Neurotecnology, Cambridge, UK) evaluated the sleep patterns. In each participant, we considered seven sleep parameters (sleep onset: S-on; sleep offset: S-off; sleep duration: SD; sleep latency: SL; movement and fragmentation index: MFI; immobility time: IT; sleep efficiency: SE) calculated over a period of five nights. The population mean cosinor applied to BED and Ctrl revealed the presence of a significant circadian rhythm in both groups (p < 0.001). The MESOR (170.0 vs 301.6 a.c., in BED and Ctrl, respectively; p < 0.01) and amplitude (157.66 vs 238.19 a.c., in BED and Ctrl, respectively p < 0.05) differed significantly between the two groups. Acrophase was not different between BED and Ctrl, as well as all sleep parameters. Both groups displayed a low level of sleep quality (SE 80.7% and 75.7% in BED and Ctrl, respectively). These data provided the first actigraphy-based evidence of RARs disruption and sleep behavior disorder in patients with BED. However, while sleep disorders could be reasonably ascribed to overweight/obesity and the related lower daily physical activity, RARs disruption in this pathology should be ascribed to factors other than reduced physical activity. The circadian timing approach can represent a novel potential tool in the treatment of patients with eating disorders. These data provide exploratory evidence of behavioral association in a small population of patients that, if confirmed in a wider number of subjects and across different populations, may lead to a revision and enhancement of interventions in BED patients.

Histological changes of the meniscus following an osteochondral lesion

In the last few years, different tissue engineering strategies have been developed for the repair of osteochondral lesions. When the osteochondral scaffold is implanted on the femoral condyle, the meniscus might be affected by the implant and might undergo a progressive degeneration. The aim of our study is to analyze the morphological changes of the meniscus following an osteochondral lesion and the implant of a biphasic scaffold. A critical osteochondral defect was generated in the medial femoral condyle of mature sheep. Three defects were left untreated, the remaining lesions were divided into three groups and treated with a biphasic substituted formed by collagen type I and Wollastonite or Wollastonite/Hydroxyapatite. Animals were sacrificed after 6 months and menisci were isolated and analyzed by arthro-CT, macroscopic evaluation and histology. The results demonstrated that the osteochondral lesion negatively affects meniscus morphology and that the osteochondral substitute only partially mitigates the meniscus degeneration.

The sportsman readjustment after transcontinental flight: a study on marathon runners

AIM

The aim of the study was to evaluate the synchronizing effect of physical activity on the rest-activity cycle after a flight across different time zones, investigating the parameters linked to sleep. The purpose of this study is to evaluate the synchronizing effect of physical activity on the sleep-activity parameters after a flight across different time zones.

METHODS

Eighteen volunteers flew from Milan to New York for the 2007 New York City Marathon. A training program, that consisted of running sessions three times a week for one month, was planned for the twelve athletes that participated in the marathon. The athletes were divided in two groups: Morning Training Group (MTG), trained from 7:00 to 9:00; Evening Training Group (ETG) from 19:00 to 21:00. The Control Group (CG), of 6 non-athletes, did not train before the flight and did not participate in the marathon. In New York, both groups of athletes trained in the morning. Two Actigraph monitoring sessions were performed in all three groups, before the Milan-New York flight and during the stay in New York. The actigraphy made it possible to calculate sleep and activity-specific parameters; sleep and activity patterns were continuously monitored using an actometer on the wrist of the non-dominant hand.

RESULTS

Sleep analysis done on the first night in New York showed a significant difference (P<0.05) in the Movement and Fragmentation Index (MFI) between MTG and ETG. In CG and MTG, the MFI increased after the flight, while in ETG, the MFI decreased. Activity analysis demonstrated that, in ETG, evening physical activity in Milan associated with morning activity in New York produced a shift in the Cosine Peak of the rhythm of activity.

CONCLUSIONS

Physical activity can have a positive effect both on sleep, by improving quality, as well as on the circadian rhythm of activity, by encouraging re-synchronization after the flight.

Resynchronization of blood pressure circadian rhythm after westward trans-7-meridian flight with and without melatonin treatment

Blood pressure (BP) of a healthy 37-yr-old male traveling from Milan to Houston was monitored for 36 h before the flight and continued for 5 d after the arrival. The rhythmometric analysis of BP data was made to investigate the rate of adaptation to a rapid rest-activity cycle shift. Since two trips were evaluated, during the second one the subject took melatonin (3 mg) before the nocturnal rest. In the first trip the BP circadian rhythm synchronization occurred on the 5th day. In the second trip melatonin promoted an immediate but unstable adaptation to the new rest-activity cycle.

The early maturation of the circadian system in newborns

The time of maturation of the circadian periodicity in humans has been differently considered. The present study aimed to investigate the existence of rhythmic variations in the body temperature of healthy full-term infants just after birth. We studied 19 healthy term newborns, nursed in their cribs at environment temperature of 25 degrees C and moderately dimmed artificial lighting during the night. Continuous recording of body temperature was performed with a solid memory recorder (Fiamarker) connected to a disposable rectal probe, during the first three days of life. Data were analyzed by means of single and mean cosinor methods and spectral analysis. All the newborns, except two, demonstrated a statistically significant circadian periodicity of temperature (p < .001). Acrophases were distributed along the 24h since the synchronization to environment was not yet completed. A clear ultradian fluctuation of body temperature was observed in all 19 newborns with an unexpected fall of temperature every three-four hours. Our data show that the maturation of the circadian system is probably almost complete in newborns, but the adjustment to the new environment can be expected in the subsequent weeks of life.