Effects of bright light treatment on psychomotor speed in athletes

Purpose: A recent study suggests that transcranial brain targeted light treatment via ear canals may have physiological effects on brain function studied by functional magnetic resonance imaging (fMRI) techniques in humans. We tested the hypothesis that bright light treatment could improve psychomotor speed in professional ice hockey players. Methods: Psychomotor speed tests with audio and visual warning signals were administered to a Finnish National Ice Hockey League team before and after 24 days of transcranial bright light or sham treatment. The treatments were given during seasonal darkness in the Oulu region (latitude 65 degrees north) when the strain on the players was also very high (10 matches during 24 days). A daily 12-min dose of bright light or sham (n = 11 for both) treatment was given every morning between 8–12 am at home with a transcranial bright light device. Mean reaction time and motor time were analyzed separately for both psychomotor tests. Analysis of variance for repeated measures adjusted for age was performed. Results: Time x group interaction for motor time with a visual warning signal was p = 0.024 after adjustment for age. In Bonferroni post-hoc analysis, motor time with a visual warning signal decreased in the bright light treatment group from 127 ± 43 to 94 ± 26 ms (p = 0.024) but did not change significantly in the sham group 121 ± 23 vs. 110 ± 32 ms (p = 0.308). Reaction time with a visual signal did not change in either group. Reaction or motor time with an audio warning signal did not change in either the treatment or sham group. Conclusion: Psychomotor speed, particularly motor time with a visual warning signal, improves after transcranial bright light treatment in professional ice-hockey players during the competition season in the dark time of the year

Association between Birth Characteristics and Cardiovascular Autonomic Function at Mid-Life

Background Low birth weight is associated with an increased risk of cardiovascular diseases in adulthood. As abnormal cardiac autonomic function is a common feature in cardiovascular diseases, we tested the hypothesis that low birth weight may also be associated with poorer cardiac autonomic function in middle-aged subjects. Methods At the age of 46, the subjects of the Northern Finland Birth Cohort 1966 were invited to examinations including questionnaires about health status and life style and measurement of vagally-mediated heart rate variability (rMSSD) from R-R intervals (RRi) and spontaneous baroreflex sensitivity (BRS) in both seated and standing positions. Maternal parameters had been collected in 1965–1966 since the 16th gestational week and birth variables immediately after delivery. For rMSSD, 1,799 men and 2,279 women without cardiorespiratory diseases and diabetes were included and 902 men and 1,020 women for BRS. The analyses were adjusted for maternal (age, anthropometry, socioeconomics, parity, gestational smoking) and adult variables (life style, anthropometry, blood pressure, glycemic and lipid status) potentially confounding the relationship between birth weight and autonomic function. Results In men, birth weight correlated negatively with seated (r = -0.058, p = 0.014) and standing rMSSD (r = -0.090, p<0.001), as well as with standing BRS (r = -0.092, p = 0.006). These observations were verified using relevant birth weight categories (<2,500 g; 2,500–3,999 g; ≥4,000 g). In women, birth weight was positively correlated with seated BRS (r = 0.081, p = 0.010), but none of the other measures of cardiovascular autonomic function. These correlations remained significant after adjustment for potential confounders (p<0.05 for all). Conclusions In men, higher birth weight was independently associated with poorer cardiac autonomic function at mid-life. Same association was not observed in women. Our findings suggest that higher, not lower, birth weight in males may contribute to less favourable cardiovascular autonomic regulation and potentially to an elevated cardiovascular risk in later life

Moderate and heavy metabolic stress interval training improve arterial stiffness and heart rate dynamics in humans

Traditional continuous aerobic exercise training attenuates age-related increases of arterial stiffness, however, training studies have not determined whether metabolic stress impacts these favourable effects. Twenty untrained healthy participants (n = 11 heavy metabolic stress interval training, n = 9 moderate metabolic stress interval training) completed 6 weeks of moderate or heavy intensity interval training matched for total work and exercise duration. Carotid artery stiffness, blood pressure contour analysis, and linear and non-linear heart rate variability were assessed before and following training. Overall, carotid arterial stiffness was reduced (p  0.05). This study demonstrates the effectiveness of interval training at improving arterial stiffness and autonomic function, however, the metabolic stress was not a mediator of this effect. In addition, these changes were also independent of improvements in aerobic capacity, which were only induced by training that involved a high metabolic stress

Inhomogeneous point-process entropy: an instantaneous measure of complexity in discrete systems

Measures of entropy have been widely used to characterize complexity, particularly in physiological dynamical systems modeled in discrete time. Current approaches associate these measures to finite single values within an observation window, thus not being able to characterize the system evolution at each moment in time. Here, we propose a new definition of approximate and sample entropy based on the inhomogeneous point-process theory. The discrete time series is modeled through probability density functions, which characterize and predict the time until the next event occurs as a function of the past history. Laguerre expansions of the Wiener-Volterra autoregressive terms account for the long-term nonlinear information. As the proposed measures of entropy are instantaneously defined through probability functions, the novel indices are able to provide instantaneous tracking of the system complexity. The new measures are tested on synthetic data, as well as on real data gathered from heartbeat dynamics of healthy subjects and patients with cardiac heart failure and gait recordings from short walks of young and elderly subjects. Results show that instantaneous complexity is able to effectively track the system dynamics and is not affected by statistical noise properties

Self-Rated Mental Stress and Exercise Training Response in Healthy Subjects

Purpose: Individual responses to aerobic training vary from almost none to a 40% increase in aerobic fitness in healthy subjects. We hypothesized that the baseline self-rated mental stress may influence to the training response. Methods: The study population included 44 healthy sedentary subjects (22 women) and 14 controls. The laboratory controlled training period was 2 weeks, including five sessions a week at an intensity of 75% of the maximum heart rate for 40 min/session. Self-rated mental stress was assessed by inquiry prior to the training period from 1 (low psychological resources and a lot of stressors in my life) to 10 (high psychological resources and no stressors in my life), respectively. Results: Mean peak oxygen uptake (VO2peak) increased from 34 ± 7 to 37 ± 7 ml kg−1 min−1 in training group (p < 0.001) and did not change in control group (from 34 ± 7 to 34 ± 7 ml kg−1 min−1). Among the training group, the self-rated stress at the baseline condition correlated with the change in fitness after training intervention, e.g., with the change in maximal power (r = 0.45, p = 0.002, W/kg) and with the change in VO2peak (r = 0.32, p = 0.039, ml kg−1 min−1). The self-rated stress at the baseline correlated with the change in fitness in both female and male, e.g., r = 0.44, p = 0.039 and r = 0.43, p = 0.045 for ΔW/kg in female and male, respectively. Conclusion: As a novel finding the baseline self-rated mental stress is associated with the individual training response among healthy females and males after highly controlled aerobic training intervention. The changes in fitness were very low or absent in the subjects who experience their psychological resources low and a lot of stressors in their life at the beginning of aerobic training intervention

Depressive Symptoms and Risk for Sudden Cardiac Death in Stable Coronary Artery Disease

AbstractThe association between the mode of death and depression in patients with stable coronary artery disease (CAD) is far from clear. We investigated the association between depressive symptoms and the mode of death including all-cause mortality, noncardiac death, sudden cardiac death (SCD), and non-SCD in stable CAD patients. Patients with angiographically documented CAD (n = 1,928) underwent a clinical examination including screening for depression symptoms with the Depression Scale (DEPS) and extensive risk profiling at the baseline. The patients were divided into quartiles based on their DEPS score. The patients entered the follow-up (median 6.3 years) during which 49 SCDs (2.5%) and 48 non-SCDs (2.5%) occurred. The incidence of SCD was 1.1% (5 events), 2.0% (9 events), 2.6% (14 events), and 4.4% (21 events) from the lowest to the highest quartile of DEPS. The patients in the highest quartile of DEPS had a fourfold elevated univariate risk (95% confidence interval 1.5 to 10.5; p = 0.006), and after adjustment for traditional risk factors, a 3.2-fold elevated multivariate risk (95% confidence interval 1.2 to 8.9, p = 0.025) for SCD compared with patients in the lowest quartile. DEPS was not associated with non-SCD or noncardiac deaths. Depressive symptoms are associated with an increased risk of SCD independently of clinical risk factors in patients with CAD. The results highlight the importance of screening for depression and emphasize the need for additional interventions to alleviate the depressive symptoms in these patients.Abstract The association between the mode of death and depression in patients with stable coronary artery disease (CAD) is far from clear. We investigated the association between depressive symptoms and the mode of death including all-cause mortality, noncardiac death, sudden cardiac death (SCD), and non-SCD in stable CAD patients. Patients with angiographically documented CAD (n = 1,928) underwent a clinical examination including screening for depression symptoms with the Depression Scale (DEPS) and extensive risk profiling at the baseline. The patients were divided into quartiles based on their DEPS score. The patients entered the follow-up (median 6.3 years) during which 49 SCDs (2.5%) and 48 non-SCDs (2.5%) occurred. The incidence of SCD was 1.1% (5 events), 2.0% (9 events), 2.6% (14 events), and 4.4% (21 events) from the lowest to the highest quartile of DEPS. The patients in the highest quartile of DEPS had a fourfold elevated univariate risk (95% confidence interval 1.5 to 10.5; p = 0.006), and after adjustment for traditional risk factors, a 3.2-fold elevated multivariate risk (95% confidence interval 1.2 to 8.9, p = 0.025) for SCD compared with patients in the lowest quartile. DEPS was not associated with non-SCD or noncardiac deaths. Depressive symptoms are associated with an increased risk of SCD independently of clinical risk factors in patients with CAD. The results highlight the importance of screening for depression and emphasize the need for additional interventions to alleviate the depressive symptoms in these patients

Lower hemoglobin levels associate with higher baroreflex sensitivity and heart rate variability

Abstract The aim of this study was to cross-sectionally examine whether hemoglobin (Hb) levels within the normal variation associate with heart rate variability (HRV) measures and baroreflex sensitivity (BRS). The study population included 733 Finnish subjects of the OPERA cohort (aged 41–59 yr, 53% males, 51.7% treated for hypertension) of whom HRV was measured from a standardized 45-min period and whose Hb levels were within the Finnish reference intervals. The low Hb tertile (mean Hb, 135 g/L) had an overall healthier metabolic profile compared with the high Hb tertile (mean Hb, 152 g/L). BRS was higher in the low Hb tertile compared with the high Hb tertile (P < 0.05). R-R interval (RRi) and standard deviation (SD) of the RRi (SDNN)index were the longest in the low Hb tertile regardless of posture. Of the spectral components of HRV, HF power was the highest in the low Hb tertile regardless of posture (P < 0.05). In a stepwise logistic regression model, BRS associated negatively with Hb levels after adjusting for covariates (B = −0.160 [−0.285; −0.035]). Similar associations were observed for SDNNindex when lying down (B = −0.105 [−0.207; −0.003]) and walking (B = −0.154 [−0.224; −0.083]). For HF power negative associations with Hb levels were observed when lying down (B = −0.110 [−0.180; −0.040]), sitting (B = −0.150 [−0.221; −0.079]), and in total analysis (B = −0.124 [−0.196; −0.053]). Overall, lower Hb levels associated independently with healthier cardiac autonomic function.Abstract The aim of this study was to cross-sectionally examine whether hemoglobin (Hb) levels within the normal variation associate with heart rate variability (HRV) measures and baroreflex sensitivity (BRS). The study population included 733 Finnish subjects of the OPERA cohort (aged 41–59 yr, 53% males, 51.7% treated for hypertension) of whom HRV was measured from a standardized 45-min period and whose Hb levels were within the Finnish reference intervals. The low Hb tertile (mean Hb, 135 g/L) had an overall healthier metabolic profile compared with the high Hb tertile (mean Hb, 152 g/L). BRS was higher in the low Hb tertile compared with the high Hb tertile (P < 0.05). R-R interval (RRi) and standard deviation (SD) of the RRi (SDNN)index were the longest in the low Hb tertile regardless of posture. Of the spectral components of HRV, HF power was the highest in the low Hb tertile regardless of posture (P < 0.05). In a stepwise logistic regression model, BRS associated negatively with Hb levels after adjusting for covariates (B = −0.160 [−0.285; −0.035]). Similar associations were observed for SDNNindex when lying down (B = −0.105 [−0.207; −0.003]) and walking (B = −0.154 [−0.224; −0.083]). For HF power negative associations with Hb levels were observed when lying down (B = −0.110 [−0.180; −0.040]), sitting (B = −0.150 [−0.221; −0.079]), and in total analysis (B = −0.124 [−0.196; −0.053]). Overall, lower Hb levels associated independently with healthier cardiac autonomic function

Cardiac structure and function across the continuum of glucose metabolism

Abstract Diabetes and prediabetes increase the risk of heart failure, but the relationship between glycated hemoglobin (HbA1c) and left ventricular systolic function in the general population is not known. This study aimed to investigate the relationship between HbA1c and global longitudinal strain (GLS) in nondiabetic and prediabetic subjects. A subpopulation of the Northern Finland Birth Cohort 1966 took part in a follow-up, including extensive medical examination and echocardiography (n = 1155), at the age of 46. The final study population included 636 healthy subjects. Normal HbA1c levels were divided into sex-specific tertiles and prediabetes, which were later pooled together. Univariate analysis after adjusted with covariates was used to compare cardiac function in HbA1c groups. HbA1c groups were defined as low (30.9 ± 1.7 mmol/mol, n = 190), medium (34.6 ± 1.0 mmol/mol, n = 189), high (37.4 ± 1.0 mmol/mol, n = 190) and prediabetes (41.0 ± 1.3 mmol/mol, n = 67) groups. Subjects with abnormal absolute GLS (<18) comprised 7.4%, 12.7%, 21.1%, and 17.9% (main effect p < 0.01) of low, medium, high HbA1c and prediabetes groups, respectively. HbA1c was not associated with any cardiac structure variables. High normal HbA1c levels and prediabetes are associated with reduced myocardial contractility in a healthy middle-aged population, potentially predicting the development of heart failure.Abstract Diabetes and prediabetes increase the risk of heart failure, but the relationship between glycated hemoglobin (HbA1c) and left ventricular systolic function in the general population is not known. This study aimed to investigate the relationship between HbA1c and global longitudinal strain (GLS) in nondiabetic and prediabetic subjects. A subpopulation of the Northern Finland Birth Cohort 1966 took part in a follow-up, including extensive medical examination and echocardiography (n = 1155), at the age of 46. The final study population included 636 healthy subjects. Normal HbA1c levels were divided into sex-specific tertiles and prediabetes, which were later pooled together. Univariate analysis after adjusted with covariates was used to compare cardiac function in HbA1c groups. HbA1c groups were defined as low (30.9 ± 1.7 mmol/mol, n = 190), medium (34.6 ± 1.0 mmol/mol, n = 189), high (37.4 ± 1.0 mmol/mol, n = 190) and prediabetes (41.0 ± 1.3 mmol/mol, n = 67) groups. Subjects with abnormal absolute GLS (<18) comprised 7.4%, 12.7%, 21.1%, and 17.9% (main effect p < 0.01) of low, medium, high HbA1c and prediabetes groups, respectively. HbA1c was not associated with any cardiac structure variables. High normal HbA1c levels and prediabetes are associated with reduced myocardial contractility in a healthy middle-aged population, potentially predicting the development of heart failure

Revealing Real-Time Emotional Responses: a Personalized Assessment based on Heartbeat Dynamics

Emotion recognition through computational modeling and analysis of physiological signals has been widely investigated in the last decade. Most of the proposed emotion recognition systems require relatively long-time series of multivariate records and do not provide accurate real-time characterizations using short-time series. To overcome these limitations, we propose a novel personalized probabilistic framework able to characterize the emotional state of a subject through the analysis of heartbeat dynamics exclusively. The study includes thirty subjects presented with a set of standardized images gathered from the international affective picture system, alternating levels of arousal and valence. Due to the intrinsic nonlinearity and nonstationarity of the RR interval series, a specific point-process model was devised for instantaneous identification considering autoregressive nonlinearities up to the third-order according to the Wiener-Volterra representation, thus tracking very fast stimulus-response changes. Features from the instantaneous spectrum and bispectrum, as well as the dominant Lyapunov exponent, were extracted and considered as input features to a support vector machine for classification. Results, estimating emotions each 10 seconds, achieve an overall accuracy in recognizing four emotional states based on the circumplex model of affect of 79.29%, with 79.15% on the valence axis, and 83.55% on the arousal axis