Background. Light exposure to the eye can influence different physiological functions, for example, the suprachiasmatic nucleus (SCN). By affecting the autonomic nervous system, the SCN may influence the heart rate variability (HRV). Standardized colored light exposure alters HRV but the results are inconsistent. In this study we investigated the effects of nonstandardized red light (approx. 640 nm) and blue (approx. 480 nm) light (approx. 50 lx) on cardiorespiratory coordination and HRV. Methods. 17 healthy subjects (7 males, age: 26.5 ± 6.2 years) were exposed to the following sequence (10 minutes each): daylight-red light-daylight-blue light-daylight. Red and blue lights were created by daylight passing through colored glass panes. Spectral measures of HRV (LF: low frequency, HF: high frequency oscillations, and sympathovagal balance LF/HF) and measures of cardiorespiratory coordination (HRR: heart respiration ratio, PCR: phase coordination ratio) were analyzed. Results. The LF component increased and the HF component decreased after red light. Consequently, LF/HF increased after red light. Furthermore, during red light HRR and PCR confined to 4 : 1, that is, 4 heartbeats during one respiratory cycle. Conclusion. Nonstandardized red and blue lights are able to alter the autonomic control reflected by HRV as well as cardiorespiratory coordination.
BackgroundIntegrative medicine (IM) integrates evidence-based Complementary and Alternative Medicine (CAM) with conventional medicine (CON). Medical schools offer basic CAM electives but in postgraduate medical training (PGMT) little has been done for the integration of CAM. An exception to this is anthroposophic medicine (AM), a western form of CAM based on CON, offering an individualized holistic IM approach. AM hospitals are part of the public healthcare systems in Germany and Switzerland and train AM in PGMT. We performed the first quality evaluation of the subjectively perceived quality of this PGMT.MethodsAn anonymous full survey of all 214 trainers (TR) and 240 trainees (TE) in all 15 AM hospitals in Germany and Switzerland, using the ETHZ questionnaire for annual national PGMT assessments in Switzerland (CH) and Germany (D), complemented by a module for AM. Data analysis included Cronbach’s alpha to assess internal consistency questionnaire scales, 2-tailed Pearson correlation of specific quality dimensions of PGMT and department size, 2-tailed Wilcoxon Matched-Pair test for dependent variables and 2-tailed Mann–Whitney U-test for independent variables to calculate group differences. The level of significance was set at p < 0.05.ResultsReturn rates were: D: TE 89/215 (41.39%), TR 78/184 (42.39%); CH: TE 19/25 (76%), TR 22/30 (73.33%). Cronbach’s alpha values for TE scales were >0.8 or >0.9, and >0.7 to >0.5 for TR scales. Swiss hospitals surpassed German ones significantly in Global Satisfaction with AM (TR and TE); Clinical Competency training in CON (TE) and AM (TE, TR), Error Management, Culture of Decision Making, Evidence-based Medicine, and Clinical Competency in internal medicine CON and AM (TE). When the comparison was restricted to departments of comparable size, differences remained significant for Clinical Competencies in AM (TE, TR), and Culture of Decision Making (TE). CON received better grades than AM in Global Satisfaction and Clinical Competency. Quality of PGMT depended on department size, working conditions and structural training features.ConclusionThe lower quality of PGMT in German hospitals can be attributed to larger departments, more difficult working conditions, and less favorable structural features for PGMT in AM, possibly also in relation to increased financial pressure.
Colored light is applied in medicine in the treatment of various diseases. The aim of this study was to investigate potential effects of exposure to blue and red light on brain and muscle blood volume ([tHb]) and tissue oxygenation (StO2) measured by noninvasive near-infrared spectrophotometry (NIRS). Ten healthy volunteers were included in a randomized crossover study. Blue light exposure leads to decreased oxygen consumption in the brain and the skeletal muscle. I ntr oductionLight of different colors (CL) is applied for various medical conditions to improve the physical, emotional or mental state of patients. Examples are the use of blue light in the treatment of the neonatal jaundice [1], a phenomenon due to the immature liver function of newborns, the application of red [2] and UV light in dermatology (physical level), and the use of bright white light to treat seasonal affective disorders [3] (emotional or mental level). It is known that blue light is strongly absorbed by the skin, suppresses melatonin production and is generally associated with coldness. In contrast, red light penetrates tissue relatively deeply and is associated with warmth. However, little is known about the effects of CL on hemodynamics and tissue oxygenation.We therefore investigated potential effects of blue and red light, being the two main colors used in medical treatments, on blood volume and tissue oxygenation in the brain and skeletal leg muscle using near-infrared spectrophotometry (NIRS). M ater ials and methodsTen healthy volunteers (5 male, 5 female; mean age 27, range 23-44 years) were measured during blue and red light exposure. Light was generated using thermal white light sources (60W, OSRAM Inc., Germany) and color filters (Lee Inc., Germany). During exposure phases the CL was projected onto a white wall. The subjects were seated in a comfortable chair facing the wall. Subjects were asked to keep their eyes open throughout the entire measurement. Otherwise the room was completely dark and instruments were shielded in order to avoid ambient light.All subjects were measured twice on different days, exposed to blue or red light in a randomized crossover protocol. The protocol consisted of 8 min baseline (darkness), 10 min CL (blue or red) exposure, followed by 16 min recovery (darkness). Blood volume, i.e. total hemoglobin concentration ([tHb] in µM) and tissue oxygen saturation (StO 2 in %) were measured with a Hamamatsu NIRO 300 instrument. One sensor was attached to the forehead and the other to the lateral calf muscle. Using a paired t-test the last 5 min of the baseline were compared to the first and last 5 min of the CL exposure, and to 3 periods of 5 min of the recovery. Blue and red exposures were compared by a linear mixed effects (LME) model (R statistical software).
Hintergrund: Die anthroposophischen Kliniken arbeiten integrativmedizinisch, indem sie konventionelle Medizin (KON) anthroposophischmedizinisch (AM) ergänzen. Die Integrativmedizin wird dabei in der ärztlichen Weiterbildung vermittelt. Im Rahmen einer erstmaligen Untersuchung der Weiterbildungsqualität an anthroposophischen Kliniken analysierten wir die Probleme dieser Weiterbildung aus Sicht der Assistenzärzte und Weiterbilder. Methodik: Im Rahmen der Erhebung führten wir eine anonymisierte Querschnittsbefragung aller Assistenzärzte und aus- und weiterbildenden Ärzte (Weiterbilder) der 15 AM-Kliniken in Deutschland (DE) und der Schweiz (CH) mit Fragebögen der Eidgenössischen Technischen Hochschule (ETH) Zürich durch. Der Fragebogen war durch ein anthroposophisches Modul ergänzt. Zudem führten wir deskriptive Statistiken zu den skalierten Fragen, einen statistischen Gruppenvergleich mittels zweiseitigem Mann-Whitney-U-Test und eine qualitative Inhaltsanalyse (Mayring) der Freitextantworten sowie eine Problemanalyse durch. Ergebnisse: Die Rücklaufquote in DE umfasste 89 von insgesamt 215 (41.39%) befragten Assistenzärzten und 78 von 184 (42.39%) Weiterbildern. In CH füllten 19 von 25 (76%) Assistenz-ärzten und 22 von 30 (73.33%) Weiterbildern die Fragebögen aus. Die Freitextoption zur Problemanalyse in DE und CH wurde von insgesamt 16 (14,8%) Assistenzärzten und 20 (20%) Weiterbildern genutzt. Zu den Hauptproblemen zählen ein Übermaß an Arbeitsbelastung, Mängel bei der Arbeitsorganisation, Kompetenzabgrenzung, interprofessionelle Zusammenarbeit, personelle und finanzielle Ressourcen (Weiterbilder), Bezahlung (Assistenzärzte DE), Praxisbezogenheit der AM (Assistenzärzte und Weiterbilder DE), Fach- oder didaktische Kompetenz der Weiterbilder, fehlendes Interesse der Assistenzärzte an AM, Aneignungs- und Umsetzungsprobleme in AM, fehlendes Weiterbildungscurriculum in AM sowie Spannungen zwischen AM und KON. Als Gründe für die Unterschiede zwischen DE und CH werden die Existenz größerer Abteilungen und das DRG-System in DE sowie bessere strukturelle Bedingungen für die AM-Weiterbildung in CH diskutiert. Schlussfolgerung: Hauptprobleme der Weiterbildung in AM betreffen zum Teil unspezifische und systemische Aspekte, aber auch spezifische Probleme der AM selbst. Um konkrete Ansatzpunkte für Problemlösungsoptionen zu schaffen, soll diese Untersuchung ergänzt werden durch eine Analyse von Problemlösungsvorschlägen aus Sicht der betroffenen Assistenzärzte und Weiterbilder.
Color light therapy is a therapeutic method in complementary medicine. In color therapy, light of two contrasting colors is often applied in a sequential order. The aim of this study was to investigate possible physiological effects, i.e., changes in the blood volume and oxygenation in the brain and calf muscle of healthy subjects who were exposed to red and blue light in sequential order. The hypothesis was that if a subject is first exposed to blue and then red light, the effect of the red light will be enhanced due to the contrastingly different characteristics of the two colors. The same was expected for blue light, if first exposing a subject to red and then to blue light. Twelve healthy volunteers (six male, six female) were measured twice on two different days by near-infrared spectroscopy during exposure to colored light. Two sequences of colored light were applied in a controlled, randomized, crossover design: first blue, then red, and vice versa. For the brain and muscle, the results showed no significant differences in blood volume and oxygenation between the two sequences, and a high interindividual physiological variability. Thus, the hypothesis had to be rejected. Comparing these data to results from a previous study, where subjects were exposed to blue and red light without sequential color changes, shows that the results of the current study appear to be similar to those of red light exposure. This may indicate that the exposure to red light was preponderant and thus effects of blue light were outweighed.
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