No abstract

Several studies have shown the differences among chronotypes in the circadian rhythm of different physiological variables. Individuals show variation in their preference for the daily timing of activity; additionally, there is an association between chronotype and sleep duration/sleep complaints. Few studies have investigated sleep quality during the week days and weekends in relation to the circadian typology using self-assessment questionnaires or actigraphy. The purpose of this study was to use actigraphy to assess the relationship between the three chronotypes and the circadian rhythm of activity levels and to determine whether sleep parameters respond differently with respect to time (weekdays versus the weekend) in Morning-types (M-types), Neither-types (N-types) and Evening-types (E-types). The morningness-eveningness questionnaire (MEQ) was administered to 502 college students to determine their chronotypes. Fifty subjects (16 M-types, 15 N-types and 19 E-types) were recruited to undergo a 7-days monitoring period with an actigraph (Actiwacth® actometers, CNT, Cambridge, UK) to evaluate their sleep parameters and the circadian rhythm of their activity levels. To compare the amplitude and the acrophase among the three chronotypes, we used a one-way ANOVA followed by the Tukey-Kramer post-hoc test. To compare the Midline Estimating Statistic of Rhythm (MESOR) among the three chronotypes, we used a Kruskal-Wallis non-parametric test followed by pairwise comparisons that were performed using Dunn's procedure with a Bonferroni correction for multiple comparisons. The analysis of each sleep parameter was conducted using the mixed ANOVA procedure. The results showed that the chronotype was influenced by sex (χ(2) with p = 0.011) and the photoperiod at birth (χ(2) with p < 0.05). Though the MESOR and amplitude of the activity levels were not different among the three chronotypes, the acrophases compared by the ANOVA post-hoc test were significantly different (p < 0.001). The ANOVA post-hoc test revealed the presence of a significant difference (p < 0.001) between the M-types (14:32 h) and E-types (16:53 h). There was also a significant interaction between the chronotype and four sleep parameters: Sleep end, Assumed Sleep, Immobility Time and Sleep Efficiency. Sleep Efficiency showed the same patterns as did Assumed Sleep and Immobility Time: the Sleep Efficiency of the E-types was poorer than that of the M- and N-types during weekdays (77.9% ± 7.0 versus 84.1% ± 4.9 and 84.1% ± 5.2) but was similar to that measured in the M- and N-types during the weekend. Sleep Latency and Movement and Fragmentation Index were not different among the three chronotypes and did not change on the weekend compared with weekdays. This study highlights two key findings: first, we observed that the circadian rhythm of activity levels was influenced by the chronotype; second, the chronotype had a significant effect on sleep parameters: the E-types had a reduced sleep quality and quantity compared with the M- and N-types during weekdays,...

Sports trainers and coaches should take into account the influence of both the time of day and chronotype effect when scheduling training sessions into specific time periods.

Italy is one of the first European epicenters of the COVID-19 pandemic. In attempts to hinder the spread of the novel coronavirus disease, Italian government hardened protective measures, from quarantine to lockdown, impacting millions of lives dramatically. Amongst the enacted restrictions, all non-essential activities were prohibited as well as all outdoor activities banned. However, at the first spur of the outbreak, for about a dozen of days, physical and sports activities were permitted, while maintaining social distancing. In this timeframe, by administering measures coming from self-determination theory and theory of planned behavior and anxiety state, in an integrated approach, we investigated the prevalence of these activities by testing, via a Structural Equation Model, the influence of such psychosocial variables on the intention to preserve physical fitness during the healthcare emergency. Through an adequate fit of the hypothesized model and a multi-group analysis, we compared the most COVID-19 hit Italian region-Lombardy-to the rest of Italy, finding that anxiety was significantly higher in the Lombardy region than the rest of the country. In addition, anxiety negatively influenced the intention to do physical activity. Giving the potential deleterious effects of physical inactivity due to personal restrictions, these data may increase preparedness of public health measures and attractiveness of recommendations, including on the beneficial effects of exercise, under circumstances of social distancing to control an outbreak of a novel infectious disease.

Osteoporosis and sarcopenia represent two major health problems with an increasing prevalence in the elderly population. The correlation between these diseases has been widely reported, leading to the development of the term "osteosarcopenia" to diagnose those patients suffering from both diseases. Several imaging methods for the diagnosis and management of osteoporosis exist, with dual-energy X-ray absorptiometry (DXA) being the most commonly used for measuring bone mineral density (BMD). Imaging technique other than DXA is represented by conventional radiography, computed tomography (CT) and ultrasound (US). Similarly, the imaging technologies used to detect loss of skeletal muscle mass in sarcopenia include DXA, CT, US and magnetic resonance imaging (MRI). These methods differ in terms of reliability, radiation exposure and costs. CT and MRI represent the gold standard for evaluating body composition (BC), but are costly and time-consuming. DXA remains the most often used technology for studying BC, being quick, widely available and with low radiation exposure.

A reliable non-invasive method to assess autonomic nervous system activity involves the evaluation of the time course of heart rate variability (HRV). HRV may vary in accordance with the degree and duration of training, and the circadian fluctuation of this variable is crucial for human health since the heart adapts to the needs of different activity levels during sleep phases or in the daytime. In the present review, time-of-day and chronotype effect on HRV in response to acute sessions of physical activity are discussed. Results are sparse and controversial; however, it seems that evening-type subjects have a higher perturbation of the autonomic nervous system (ANS), with slowed vagal reactivation and higher heart rate values in response to morning exercise than morning types. Conversely, both chronotype categories showed similar ANS activity during evening physical tasks, suggesting that this time of day seems to perturb the HRV circadian rhythm to a lesser extent. The control for chronotype and time-of-day effect represents a key strategy for individual training schedules, and, in perspective, for primary injury prevention.

Objective In a convenience sample of athletes, we conducted a survey of COVID-19-mediated lockdown (termed ‘lockdown’ from this point forward) effects on: (i) circadian rhythms; (ii) sleep; (iii) eating; and (iv) training behaviors. Methods In total, 3911 athletes [mean age: 25.1 (range 18–61) years, 1764 female (45%), 2427 team-sport (63%) and 1442 elite (37%) athletes] from 49 countries completed a multilingual cross-sectional survey including the Pittsburgh Sleep Quality Index and Insomnia Severity Index questionnaires, alongside bespoke questions about napping, training, and nutrition behaviors. Results Pittsburgh Sleep Quality Index (4.3 ± 2.4 to 5.8 ± 3.1) and Insomnia Severity Index (4.8 ± 4.7 to 7.2 ± 6.4) scores increased from pre- to during lockdown ( p < 0.001). Pittsburgh Sleep Quality Index was predominantly influenced by sleep-onset latency ( p < 0.001; + 29.8%), sleep efficiency ( p < 0.001; − 21.1%), and total sleep time ( p < 0.001; − 20.1%), whilst Insomnia Severity Index was affected by sleep-onset latency ( p < 0.001; + 21.4%), bedtime ( p < 0.001; + 9.4%), and eating after midnight ( p < 0.001; + 9.1%). During lockdown, athletes reported fewer training sessions per week (− 29.1%; d = 0.99). Athletes went to bed (+ 75 min; 5.4%; d = 1.14) and woke up (+ 150 min; 34.5%; d = 1.71) later during lockdown with an increased total sleep time (+ 48 min; 10.6%; d = 0.83). Lockdown-mediated circadian disruption had more deleterious effects on the sleep quality of individual-sport athletes compared with team-sport athletes ( p < 0.001; d = 0.41), elite compared with non-elite athletes ( p = 0.028; d = 0.44) and older compared with younger ( p = 0.008; d = 0.46) athletes. Conclusions These lockdown-induced behavioral changes reduced sleep quality and increased insomnia in athletes. Data-driven and evidence-based recommendations to counter these include, but are not limited to: (i) early outdoor training; (ii) regular meal scheduling (whilst avoiding meals prior to bedtime and caffeine in the evening) with appropriate composition; (iii) regular bedtimes and wake-up times; and (iv) avoidance of long and/or late naps. Supplementary Information The online version contains supplementary material available at 10.1007/s40279-021-01601-y.

Adequate plasmatic Vitamin D levels are crucial to maintain calcium homeostasis and bone metabolism both in the general population and in athletes. Correct dietary supply and a regular sun exposure are fundamental for allowing the desired and effective fitness level. Past studies highlighted a scenario of Vitamin D insufficiency among professional soccer players in several countries, especially in North Europe, whilst a real deficiency in athletes is rare. The typical seasonal fluctuations of Vitamin D are wrongly described transversally in athletes belonging to teams that play at different latitudes and a chronobiologic approach studying the Vitamin D circannual rhythm in soccer players has not been described yet. Therefore, we studied plasma vitamin D, cortisol, testosterone, and creatin kinase (CK) concentrations in three different Italian professional teams training at the same latitude during a period of two consecutive competitive seasons (2013 and 2014). In this retrospective observational study, 167 professional soccer players were recruited (mean age at sampling 25.1 ± 4.7 years) and a total of 667 blood drawings were carried out to determine plasma 25(OH)D, serum cortisol, serum testosterone and CK levels. Testosterone to cortisol ratio (TC) was calculated based as a surrogate marker of overtraining and psychophysical stress and each athlete was drawn until a maximum of 5 times per season. Data extracted by a subgroup of players that underwent at least 4 sample drawings along a year (N = 45) were processed with the single and population mean cosinor tests to evaluate the presence of circannual rhythms: the amplitude (A), acrophase (Φ) and the MESOR (M) are described. In total, 55 players (32.9%) had an insufficient level of 25(OH)D during the seasons and other 15 athletes (9.0%) showed, at least once, a deficiency status of Vitamin D. The rhythmometric analyses applied to the data of Vitamin D revealed the presence of a significant circannual rhythm (p < 0.001) with the acrophase that occurred in August; the rhythms of Vitamin D levels were not different neither among the three soccer teams nor between competitive seasons. Cortisol, testosterone and TC showed significant circannual rhythms (p < 0.001): cortisol registered an acrophase during winter (February) while testosterone and TC registered their peaks in the summer months (July). On the contrary, CK did not display any seasonal fluctuations. In addition, we observed weak but significant correlations between 25(OH)D versus testosterone (r = 0.29 and p < 0.001), cortisol (r = -0.27 and p < 0.001) and TC (r = 0.37 and p < 0.001). No correlation was detected between Vitamin D and CK. In conclusion, the correct chronobiologic approach in the study of annual variations of Vitamin D, cortisol and testosterone could be decisive in the development of more specific supplementation and injury prevention strategies by athletic trainers and physicians.