Methods for assessing change in brain plasticity at night and psychological resilience during daytime between repeated long-duration space missions.

This study was designed to examine the feasibility of analyzing heart rate variability (HRV) data from repeat-flier astronauts at matching days on two separate missions to assess any effect of repeated missions on brain plasticity and psychological resilience, as conjectured by Demertzi. As an example, on the second mission of a healthy astronaut studied about 20 days after launch, sleep duration lengthened, sleep quality improved, and spectral power (ms2) co-varying with activity of the salience network (SN) increased at night. HF-component (0.15-0.50 Hz) increased by 61.55%, and HF-band (0.30-0.40 Hz) by 92.60%. Spectral power of HRV indices during daytime, which correlate negatively with psychological resilience, decreased, HF-component by 22.18% and HF-band by 37.26%. LF-component and LF-band, reflecting activity of the default mode network, did not change significantly. During the second mission, 24-h acrophases of HRV endpoints did not change but the 12-h acrophase of TF-HRV did (P < 0.0001), perhaps consolidating the circadian system to help adapt to space by taking advantage of brain plasticity at night and psychological resilience during daytime. While this N-of-1 study prevents drawing definitive conclusions, the methodology used herein to monitor markers of brain plasticity could pave the way for further studies that could add to the present results.

Appropriate Circadian-Circasemidian Coupling Protects Blood Pressure from Morning Surge and Promotes Human Resilience and Wellbeing.

Background: Blood pressure (BP) variability is involved in the appraisal of threat and safety, and can serve as a potential marker of psychological resilience against stress. The relationship between biological rhythms of BP and resilience was cross-sectionally assessed by 7-day/24-hour chronobiologic screening in a rural Japanese community (Tosa), with focus on the 12-hour component and the "circadian-circasemidian coupling" of systolic (S) BP. Subjects and Methods: Tosa residents (N = 239, 147 women, 23-74 years), free of anti-hypertensive medication, completed 7-day/24-hour ambulatory BP monitoring. The circadian-circasemidian coupling was determined individually by computing the difference between the circadian phase and the circasemidian morning-phase of SBP. Participants were classified into three groups: those with a short coupling interval of about 4.5 hours (Group A), those with an intermediate coupling interval of about 6.0 hours (Group B), and those with a long coupling interval of about 8.0 hours (Group C). Results: Residents of Group B who showed optimal circadian-circasemidian coordination had less pronounced morning and evening SBP surges, as compared to residents of Group A (10.82 vs 14.29 mmHg, P < 0.0001) and Group C (11.86 vs 15.21 mmHg, P < 0.0001), respectively. The incidence of morning or evening SBP surge was less in Group B than in Group A (P < 0.0001) or Group C (P < 0.0001). Group B residents showed highest measures of wellbeing and psychological resilience, assessed by good relation with friends (P < 0.05), life satisfaction (P < 0.05), and subjective happiness (P < 0.05). A disturbed circadian-circasemidian coupling was associated with elevated BP, dyslipidemia, arteriosclerosis and a depressive mood. Conclusion: The circadian-circasemidian coupling of SBP could serve as a new biomarker in clinical practice to guide precision medicine interventions aimed at achieving properly timed rhythms, and thereby resilience and wellbeing.

Unconscious mind activates central cardiovascular network and promotes adaptation to microgravity possibly anti-aging during 1-year-long spaceflight.

The intrinsic cardiovascular regulatory system (ß, 0.00013-0.02 Hz) did not adapt to microgravity after a 6-month spaceflight. The infraslow oscillation (ISO, 0.01-0.10 Hz) coordinating brain dynamics via thalamic astrocytes plays a key role in the adaptation to novel environments. We investigate the adaptive process of a healthy astronaut during a 12-month-long spaceflight by analyzing heart rate variability (HRV) in the LF (0.01-0.05 Hz) and MF1 (0.05-0.10 Hz) bands for two consecutive days on four occasions: before launch, at 1-month (ISS01) and 11-month (ISS02) in space, and after return to Earth. Alteration of ß during ISS01 improved during ISS02 (P = 0.0167). During ISS01, LF and MF1 bands, reflecting default mode network (DMN) activity, started to increase at night (by 43.1% and 32.0%, respectively), when suprachiasmatic astrocytes are most active, followed by a 25.9% increase in MF1-band throughout the entire day during ISS02, larger at night (47.4%) than during daytime. Magnetic declination correlated positively with ß during ISS01 (r = 0.6706, P < 0.0001) and ISS02 (r = 0.3958, P = 0.0095). Magnetic fluctuations may affect suprachiasmatic astrocytes, and the DMN involving ISOs and thalamic astrocytes may then be activated, first at night, then during the entire day, a mechanism that could perhaps promote an anti-aging effect noted in other investigations.

Astronauts well-being and possibly anti-aging improved during long-duration spaceflight.

This study assesses how circadian rhythms of heart rate (HR), HR variability (HRV) and activity change during long-term missions in space and how they relate to sleep quality. Ambulatory 48-h ECG and 96-h actigraphy were performed four times on ten healthy astronauts (44.7 ± 6.9 years; 9 men): 120.4 ± 43.7 days (Before) launch; 21.1 ± 2.5 days (ISS01) and 143.0 ± 27.1 days (ISS02) after launch; and 86.6 ± 40.6 days (After) return to Earth. Sleep quality was determined by sleep-related changes in activity, RR-intervals, HRV HF- and VLF-components and LF-band. The circadian amplitude of HR (HR-A) was larger in space (ISS01: 12.54, P = 0.0099; ISS02: 12.77, P = 0.0364) than on Earth (Before: 10.90; After: 10.55 bpm). Sleep duration in space (ISS01/ISS02) increased in 3 (Group A, from 370.7 to 388.0/413.0 min) and decreased in 7 (Group B, from 454.0 to 408.9/381.6 min) astronauts. Sleep quality improved in Group B from 7.07 to 8.36 (ISS01) and 9.36 (ISS02, P = 0.0001). Sleep-related parasympathetic activity increased from 55.2% to 74.8% (pNN50, P = 0.0010) (ISS02). HR-A correlated with the 24-h (r = 0.8110, P = 0.0044), 12-h (r = 0.6963, P = 0.0253), and 48-h (r = 0.6921, P = 0.0266) amplitudes of the magnetic declination index. These findings suggest associations of mission duration with increased well-being and anti-aging benefitting from magnetic fluctuations.

A population-based cross-sectional study of the association between periodontitis and arterial stiffness among the older Japanese population.

OBJECTIVE: To investigate the potential association between periodontitis and arterial stiffness among the older Japanese population. BACKGROUND: The prevalence of periodontitis is increasing in Japanese older adults. Arterial stiffness increases the risks of cardiovascular events and death, morbidity, and dementia. METHODS: This secondary analysis of data from a cross-sectional study evaluated the periodontal inflamed surface area (PISA), reflecting the amount of inflamed periodontal tissue that was estimated by a full-mouth periodontal examination. Severe periodontitis was defined per the parameters provided by the Centers for Disease Control/American Academy of Periodontology. The Cardio-Ankle Vascular Index (CAVI) was used for measuring the overall stiffness of the artery, and higher CAVI indicated increased arterial stiffness. An ordinal logistic regression model was used to evaluate the association between periodontitis and arterial stiffness. RESULTS: The analysis included 185 Japanese adults [35% men; age, mean (standard deviation) 80.2 (4.4) years]. The average PISA and the prevalence of severe periodontitis were 64.4 mm2 and 27.6%, respectively; 54 (29.2%), 56 (30.3%), and 75 (40.5%) participants were stratified to the CAVI < 9, 9 ≤ CAVI <10, and CAVI ≥ 10 groups, respectively. After adjusting for potential confounders, the odds ratio of the prevalence and severity of arterial stiffness evaluated using CAVI was 1.06 [95% confidence interval (CI) 1.01 to 1.10] for PISA per 10 mm2 and 2.12 (95% CI 1.09 to 4.11) for severe periodontitis. CONCLUSION: Periodontitis was associated with arterial stiffness among Japanese older adults. Further studies are needed to investigate whether arterial stiffness is an intermediate factor in the pathway between periodontitis and systemic diseases, including cardiovascular disease and dementia.

Some Near- and Far-Environmental Effects on Human Health and Disease with a Focus on the Cardiovascular System.

Environmental effects on human physiopathology are revisited herein from a chronobiologic viewpoint, with a focus on the cardiovascular system. Physiological variables undergo recurring changes that are predictable in a statistical, albeit not deterministic way. Biological rhythms cover a broad range of frequencies, which are usually shared by the environment as "co-periodisms". Some of these photic and non-photic periodicities shared by the environment and physiopathology are reviewed herein, together with their possible underlying mechanisms. A plausible cascade of events from the long-period cycles found in the cosmic environment to those affecting the Earth's atmosphere and weather conditions is presented, which may shed light on how they may shape the cycles characterizing human health. Maps of important cycles shared between the environment and physiopathology are being catalogued in an atlas of chronomes with the goal of distinguishing between strong and weak associations and providing an estimate of the lag that can be anticipated before observing physiological changes.

Repeated ambulatory monitoring reveals an evening rise in blood pressure in a Japanese population.

Recent studies have revealed 2 peaks in the onset of cardiovascular events, 1 in the morning and another in the evening. We evaluated whether blood pressure (BP) also rises in the morning/evening and identified the determinants of evening BP rise using 24-hour ambulatory BP monitoring for 7 consecutive days. We identified 2 BP peaks, 1 in the morning (0-3 hours after waking) and 1 in the evening (9-12 hours after waking). Subjects were subclassified according to the extent of evening BP rise: those in the top quartile (≥6.45 mm Hg, n = 34; ER group) vs all others. After adjustment for age, sex, and 24-hour systolic BP, evening BP rise was associated with the use of antihypertensive medications [odds ratio (OR), 3.57; 95% confidence interval (CI), 1.46-8.74; P = .01] and estimated glomerular filtration rate (OR, 0.96; 95% CI, 0.93-0.99; P = .04), confirming its association with antihypertensive medication use and renal dysfunction.

Anti-aging effects of long-term space missions, estimated by heart rate variability.

Reports that aging slows down in space prompted this investigation of anti-aging effects in humans by analyzing astronauts' heart rate variability (HRV). Ambulatory 48-hour electrocardiograms from 7 astronauts (42.1 ± 6.8 years; 6 men) 20.6 ± 2.7 days (ISS01) and 138.6 ± 21.8 days (ISS02) after launch were divided into 24-hour spans of relative lower or higher magnetic disturbance, based on geomagnetic measures in Tromso, Norway. Magnetic disturbances were significantly higher on disturbed than on quiet days (ISS01: 72.01 ± 33.82 versus 33.96 ± 17.90 nT, P = 0.0307; ISS02: 71.06 ± 51.52 versus 32.53 ± 27.27 nT, P = 0.0308). SDNNIDX was increased on disturbed days (by 5.5% during ISS01, P = 0.0110), as were other HRV indices during ISS02 (SDANN, 12.5%, P = 0.0243; Triangular Index, 8.4%, P = 0.0469; and TF-component, 17.2%, P = 0.0054), suggesting the action of an anti-aging or longevity effect. The effect on TF was stronger during light (12:00-17:00) than during darkness (0:00-05:00) (P = 0.0268). The brain default mode network (DMN) was activated, gauged by increases in the LF-band (9.7%, P = 0.0730) and MF1-band (9.9%, P = 0.0281). Magnetic changes in the magnetosphere can affect and enhance HRV indices in space, involving an anti-aging or longevity effect, probably in association with the brain DMN, in a light-dependent manner and/or with help from the circadian clock.

The effect of night shift work on the expression of clock genes in beard hair follicle cells.

OBJECTIVE: Shift work encompasses a broad range of work time arrangements. However, how shift work affects the circadian expression of clock genes remains to be explored. The objective of this study was to evaluate the pattern of clock gene expression in shift workers in the field. METHODS: We examined clock gene expression in Japanese men who work: (1) one night shift followed by a day off (caregivers: nurses and doctors; the one-night group); (2) three or more consecutive night shifts (factory workers; the consecutive-night group); or (3) daytime only (the daytime group), using beard follicle samples. The expression of Period3, Nuclear Receptor Subfamily 1 Group D Member 1 (Nr1d1), and Nuclear Receptor Subfamily 1 Group D Member 2 (Nr1d2) was examined by real-time polymerase chain reaction. RESULTS: Period3 expression in the daytime and one-night groups together with Nr1d2 expression in the one-night group fitted a 24-h-period cosine curve better than in the consecutive-night group (p = 0.004, 0.012, and 0.001, respectively). The level of overall Period3 gene expression, calibrated with that of 18S-rRNA, was decreased in the consecutive-night group compared with that in the daytime group (p = 0.006). The patterns of Period3 and Nr1d2 expression in the daytime and one-night groups were more coherent than those in the consecutive-night group. CONCLUSIONS: These results suggest that night shift work affects the rhythms and levels of circadian Period3 and Nr1d2 expression dependent on the shift schedule or type of the shift; however, there is substantial variation between individuals.

Coefficients in the CAVI Equation and the Comparison Between CAVI With and Without the Coefficients Using Clinical Data.

AIM: The Cardio-Ankle Vascular Index (CAVI) is a stiffness index of the arterial tree from the origin of the aorta to the ankle, independent of blood pressure at the time of measurement. The CAVI equation includes the coefficients "a" and "b" to adjust it to the value of Hasegawa's pulse wave velocity, which is compensated for at 80 mmHg of diastolic pressure. To verify this adjustment with the coefficients, the clinical significance of CAVI and CAVI without the coefficients (haß) were compared in both an epidemiological study and an acute clinical study. METHODS: In the epidemiological study, the significances of CAVI and haß among people with or without coronary risks such as hypertension, dyslipidemia, hyperglycemia, and abnormal electrocardiography change, were compared. In the acute clinical study, nitroglycerin was administered to subjects in a control group and to coronary artery disease patients, observing CAVI and haß values over a 20-min period. RESULTS: There was no discrepancy in terms of statistically significant differences between CAVI and haß among subjects with or without risk factors. Furthermore, there was also no discrepancy in terms of statistically significant differences between CAVI and haß during the changes of those values following nitroglycerin administration over a 20-min period. CONCLUSION: In both the epidemiologic and clinical studies, there was no discrepancy in terms of significant differences between CAVI and haß. These results suggest that both are valid as indices of stiffness of the arterial tree from the origin of the aorta to the ankle.

Circadian challenge of astronauts' unconscious mind adapting to microgravity in space, estimated by heart rate variability.

It is critical that the regulatory system functions well in space's microgravity. However, the "intrinsic" cardiovascular regulatory system (ß), estimated by the fractal scaling of heart rate variability (HRV) (0.0001-0.01 Hz), does not adapt to the space environment during long-duration (6-month) space flights. Neuroimaging studies suggest that the default mode network (DMN) serves a broad adaptive purpose, its topology changing over time in association with different brain states of adaptive behavior. Hypothesizing that HRV varies in concert with changes in brain's functional connectivity, we analyzed 24-hour HRV records from 8 healthy astronauts (51.8 ± 3.7 years; 6 men) on long (174.5 ± 13.8 days) space missions, obtained before launch, after about 21 (ISS01), 73 (ISS02), and 156 (ISS03) days in space, and after return to Earth. Spectral power in 8 frequency regions reflecting activity in different brain regions was computed by maximal entropy. Improved ß (p < 0.05) found in 4 astronauts with a positive activation in the "HRV slow-frequency oscillation" (0.10-0.20 Hz) occurred even in the absence of consciousness. The adaptive response was stronger in the evening and early sleep compared to morning (p = 0.039). Brain functional networks, the DMN in particular, can help adapt to microgravity in space with help from the circadian clock.

Self-rated health is associated with subsequent functional decline among older adults in Japan.

BACKGROUND: Previous studies have reported that self-rated health (SRH) predicts subsequent mortality. However, less is known about the association between SRH and functional ability. The aim of this study was to examine whether SRH predicts decline in basic activities of daily living (ADL), even after adjustment for depression, among community-dwelling older adults in Japan. METHODS: A three-year prospective cohort study was conducted among 654 residents aged 65 years and older without disability in performing basic ADL at baseline. SRH was assessed using a visual analogue scale (range; 0-100), and dichotomized into low and high groups. Information on functional ability, sociodemographic factors, depressive symptoms, and medical conditions were obtained using a self-administered questionnaire. Logistic regression analysis was used to examine the association between baseline SRH and functional decline three years later. RESULTS: One hundred and eight (16.5%) participants reported a decline in basic ADL at the three-year follow-up. Multiple logistic regression analysis showed that the low SRH group had a higher risk for functional decline compared to the high SRH group, even after controlling for potential confounding factors (odds ratio (OR) = 2.4; 95% confidence interval (CI) = 1.3-4.4). Furthermore, a 10-point difference in SRH score was associated with subsequent functional decline (OR = 1.37; 95% CI = 1.16-1.61). CONCLUSIONS: SRH was an independent predictor of functional decline. SRH could be a simple assessment tool for predicting the loss or maintenance of functional ability in community-dwelling older adults. Positive self-evaluation might be useful to maintain an active lifestyle and stay healthy.

Sleep quality among elderly high-altitude dwellers in Ladakh.

It has been already known that people who temporarily stay at high altitude may develop insomnia as a symptom of acute mountain sickness. However, much less is known about people living at high altitude. The aim of this study was to determine the effect of high altitude environment on sleep quality for the elderly who have been living at high altitude for their whole lives. A cross-sectional study was conducted in Domkhar valley at altitudes of 2800-4200m, Ladakh. Sleep quality was assessed using Insomnia Severity Index (ISI). Measurement items include body mass index, blood pressure, blood sugar, hemoglobin, timed Up and Go test, oxygen saturation during wakefulness, respiratory function test, Oxford Knee Score (OKS), and Geriatric Depression Scale (GDS), and so on. The participants were Ladakhi older adults aged 60 years or over (n=112) in Domkhar valley. The participation rate was 65.1% (male: female=47:65, mean age: 71.3 years and 67.9 years, respectively). The prevalence of the high score of ISI (8 or more) was 15.2% (17 out of 112). Altitude of residence was significantly correlated with ISI. Stepwise multiple regression analysis showed that OKS and altitude of residence were significantly related with ISI.

Chronobiology of Aging: A Mini-Review.

Aging is generally associated with weakening of the circadian system. The circadian amplitude is reduced and the circadian acrophase becomes more labile, tending to occur earlier with advancing age. As originally noted by Franz Halberg, similar features are observed in the experimental laboratory after bilateral lesioning of the suprachiasmatic nuclei, suggesting the involvement of clock genes in the aging process as they are in various disease conditions. Recent work has been shedding light on underlying pathways involved in the aging process, with the promise of interventions to extend healthy life spans. Caloric restriction, which is consistently and reproducibly associated with prolonging life in different animal models, is associated with an increased circadian amplitude. These results indicate the critical importance of chronobiology in dealing with problems of aging, from the circadian clock machinery orchestrating metabolism to the development of geroprotectors. The quantitative estimation of circadian rhythm characteristics interpreted in the light of time-specified reference values helps (1) to distinguish effects of natural healthy aging from those associated with disease and predisease; (2) to detect alterations in rhythm characteristics as markers of increased risk before there is overt disease; and (3) to individually optimize by timing prophylactic and/or therapeutic interventions aimed at restoring a disturbed circadian system and/or enhancing a healthy life span. Mapping changes in amplitude and/or acrophase that may overshadow any change in average value also avoids drawing spurious conclusions resulting from data collected at a fixed clock hour. Timely risk detection combined with treatment optimization by timing (chronotherapy) is the goal of several ongoing comprehensive community-based studies focusing on the well-being of the elderly, so that longevity is not achieved at the cost of a reduced quality of life.

Influence of cerebral white matter hyperintensities on cognitive impairment in elderly medical patients.

AIM: We investigated the characteristics of elderly medical patients with white matter hyperintensities on magnetic resonance imaging. METHODS: A total of 213 patients (123 men and 90 women; mean age 74.8 years) reported their history of hypertension, diabetes, dyslipidemia, previous stroke, coronary heart disease and chronic kidney disease (CKD). All patients completed the Mini-Mental State Examination and Geriatric Depression Scale. White matter hyperintensities were evaluated for the periventricular region, basal ganglia (BGH), deep white matter and infratentorial region, and brain atrophy was calculated as bicaudate ratios. RESULTS: Patients with cognitive impairment (Mini-Mental State Examination score < 24) were significantly older (P = 0.001), had periventricular region hyperintensities (P = 0.029) and BGH (P = 0.0015), and showed atrophy (P < 0.0001). Logistic regression showed that cognitive impairment was predicted by stroke (OR 2.5, 95% CI 0.033-0.894, P = 0.036) and atrophy (OR 8.43, 95% CI 5.71-37.0, P = 0.0109). Multiple regressions showed that BGH was associated with CKD (ß = 0.213; P = 0.003), and infratentorial region was associated with stroke (ß = 0.157; P =0.035) and CKD (ß = 0.172; P = 0.016). Periventricular region was associated with age (ß = 0.2; P = 0.011) and Geriatric Depression Scale (ß = 0.151; P = 0.037), and deep white matter hyperintensities with age (ß = 0.189; P = 0.016). CONCLUSIONS: Although cognitive impairment in elderly medical patients is associated with stroke and brain atrophy, white matter hyperintensities, especially BGH and infratentorial region, are associated with cognitive decline in relation to CKD. Geriatr Gerontol Int 2017; 17: 1488-1493.

Glucose intolerance associated with hypoxia in people living at high altitudes in the Tibetan highland.

OBJECTIVES: To clarify the association between glucose intolerance and high altitudes (2900-4800 m) in a hypoxic environment in Tibetan highlanders and to verify the hypothesis that high altitude dwelling increases vulnerability to diabetes mellitus (DM) accelerated by lifestyle change or ageing. DESIGN: Cross-sectional epidemiological study on Tibetan highlanders. PARTICIPANTS: We enrolled 1258 participants aged 40-87 years. The rural population comprised farmers in Domkhar (altitude 2900-3800 m) and nomads in Haiyan (3000-3100 m), Ryuho (4400 m) and Changthang (4300-4800 m). Urban area participants were from Leh (3300 m) and Jiegu (3700 m). MAIN OUTCOME MEASURE: Participants were classified into six glucose tolerance-based groups: DM, intermediate hyperglycaemia (IHG), normoglycaemia (NG), fasting DM, fasting IHG and fasting NG. Prevalence of glucose intolerance was compared in farmers, nomads and urban dwellers. Effects of dwelling at high altitude or hypoxia on glucose intolerance were analysed with the confounding factors of age, sex, obesity, lipids, haemoglobin, hypertension and lifestyle, using multiple logistic regression. RESULTS: The prevalence of DM (fasting DM)/IHG (fasting IHG) was 8.9% (6.5%)/25.1% (12.7%), respectively, in all participants. This prevalence was higher in urban dwellers (9.5% (7.1%)/28.5% (11.7%)) and in farmers (8.5% (6.1%)/28.5% (18.3%)) compared with nomads (8.2% (5.7%)/15.7% (9.7%)) (p=0.0140/0.0001). Dwelling at high altitude was significantly associated with fasting IHG+fasting DM/fasting DM (ORs for >4500 and 3500-4499 m were 3.59/4.36 and 2.07/1.76 vs <3500 m, respectively). After adjusting for lifestyle change, hypoxaemia and polycythaemia were closely associated with glucose intolerance. CONCLUSIONS: Socioeconomic factors, hypoxaemia and the effects of altitudes >3500 m play a major role in the high prevalence of glucose intolerance in highlanders. Tibetan highlanders may be vulnerable to glucose intolerance, with polycythaemia as a sign of poor hypoxic adaptation, accelerated by lifestyle change and ageing.

Long-term exposure to space's microgravity alters the time structure of heart rate variability of astronauts.

BACKGROUND: Spaceflight alters human cardiovascular dynamics. The less negative slope of the fractal scaling of heart rate variability (HRV) of astronauts exposed long-term to microgravity reflects cardiovascular deconditioning. We here focus on specific frequency regions of HRV. METHODS: Ten healthy astronauts (8 men, 49.1 ± 4.2 years) provided five 24-hour electrocardiographic (ECG) records: before launch, 20.8 ± 2.9 (ISS01), 72.5 ± 3.9 (ISS02) and 152.8 ± 16.1 (ISS03) days after launch, and after return to Earth. HRV endpoints, determined from normal-to-normal (NN) intervals in 180-min intervals progressively displaced by 5 min, were compared in space versus Earth. They were fitted with a model including 4 major anticipated components with periods of 24 (circadian), 12 (circasemidian), 8 (circaoctohoran), and 1.5 (Basic Rest-Activity Cycle; BRAC) hours. FINDINGS: The 24-, 12-, and 8-hour components of HRV persisted during long-term spaceflight. The 90-min amplitude became about three times larger in space (ISS03) than on Earth, notably in a subgroup of 7 astronauts who presented with a different HRV profile before flight. The total spectral power (TF; p < 0.05) and that in the ultra-low frequency range (ULF, 0.0001-0.003 Hz; p < 0.01) increased from 154.9 ± 105.0 and 117.9 ± 57.5 msec2 (before flight) to 532.7 ± 301.3 and 442.4 ± 202.9 msec2 (ISS03), respectively. The power-law fractal scaling ß was altered in space, changing from -1.087 ± 0.130 (before flight) to -0.977 ± 0.098 (ISS01), -0.910 ± 0.130 (ISS02), and -0.924 ± 0.095 (ISS03) (invariably p < 0.05). INTERPRETATION: Most HRV changes observed in space relate to a frequency window centered around one cycle in about 90 min. Since the BRAC component is amplified in space for only specific HRV endpoints, it is likely to represent a physiologic response rather than an artifact from the International Space Station (ISS) orbit. If so, it may offer a way to help adaptation to microgravity during long-duration spaceflight.

Predictors of difficulty in carrying out basic activities of daily living among the old-old: A 2-year community-based cohort study.

AIM: To present practical predictors for the difficulty of carrying out basic activities of daily living (ADL) among the old-old during a 2-year period. METHODS: Assessment was carried out using data obtained from the Tosa Longitudinal Aging Study, a community-based cohort survey on geriatric functions in the elderly. Predictor variables measured at baseline included age; sex; height; weight; blood pressure; oxygen saturation; neurobehavioral functions, such as Mini-Mental State Examination, Kohs Block Design test, Timed Up and Go test, button score, functional reach test, geriatric depression scale, cardio-ankle vascular index, ankle brachial pressure index; and blood chemical results, such as hemoglobin, fasting blood sugar, hemoglobin A1c, serum lipids, serum albumin and serum creatinine. The outcome variable was the presence of difficulties while carrying out basic ADL after 2 years. RESULTS: Age of ≥85 years, Timed Up and Go test of ≥15 s, button score of >17 s and presence of knee pain were independent predictors of difficulty in carrying out basic ADL after 2 years. Elderly individuals who have had at least two positive findings out of these four variables were likely to have impaired basic ADL during a 2-year period with a positive predictive value of 52.0%, negative predictive value of 90.2%, sensitivity of 70.3% and specificity of 80.8%. CONCLUSIONS: Assessment of age, Timed Up and Go test, manual dexterity, and presence of knee pain is a useful and relevant way to identify patients who should be informed about their likelihood of developing difficulties in carrying out basic ADL.

Erratum: Intrinsic cardiovascular autonomic regulatory system of astronauts exposed long-term to microgravity in space: observational study.

[This corrects the article DOI: 10.1038/npjmgrav.2015.18.].