Browsing by Subject "HEART-RATE-VARIABILITY"

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  • Orjatsalo, Maija; Partinen, Eemil; Wallukat, Gerd; Alakuijala, Anniina; Partinen, Markku (2021)
    Study objectives: Narcolepsy type 1 is a rare hypersomnia of central origin, which is caused by loss of hypothalamic neurons that produce the neuropeptides hypocretin-1 and -2. Hypocretin-containing nerve terminals are found in areas known to play a central role in autonomic control and in pain signaling. Cholinergic M2 receptors are found in brain areas involved with the occurrence of hallucinations and cataplexy. In addition to classical symptoms of narcolepsy, the patients suffer frequently from autonomic dysfunction, chronic pain, and hypnagogic/hypnopompic hallucinations. We aimed to test whether narcolepsy type 1 patients have autoantibodies against autonomic beta 2 adrenergic receptor, M2 muscarinic receptors, or nociception receptors. Methods: We tested the serum of ten narcolepsy type 1 patients (five female) for activating beta 2 adrenergic receptor autoantibodies, M2 muscarinic receptor autoantibodies, and nociception receptor autoantibodies. Results: Ten of ten patients were positive for muscarinic M2 receptor autoantibodies (P <0.001), 9/10 were positive for autoantibodies against nociception receptors (P <0.001), and 5/10 were positive for beta 2 adrenergic receptor autoantibodies (P <0.001). Conclusions: Narcolepsy type 1 patients harbored activating autoantibodies against M2 muscarinic receptors, nociception receptors, and beta 2 adrenergic receptors. M2 receptor autoantibodies may be related to the occurrence of cataplexy and, moreover, hallucinations in narcolepsy since they are found in the same brain areas that are involved with these symptoms. The occurrence of nociception receptor autoantibodies strengthens the association between narcolepsy type 1 and pain. The connection between narcolepsy type 1, autonomic complaints, and the presumed cardiovascular morbidity might be associated with the occurrence of beta 2 adrenergic receptor autoantibodies. On the other hand, the presence of the autoantibodies may be secondary to the destruction of the hypocretin pathways. (C) 2020 Elsevier B.V. All rights reserved.
  • Karvonen, Risto; Sipola, Marika; Kiviniemi, Antti; Tikanmäki, Marjaana; Järvelin, Marjo-Riitta; Eriksson, Johan G.; Tulppo, Mikko; Vääräsmäki, Marja; Kajantie, Eero (2019)
    Objective To evaluate cardiac autonomic function in adults born preterm. Study design We studied the association between prematurity and cardiac autonomic function using heart rate variability measurements in 600 adults (mean age of 23.3 years) from a geographically based cohort in Northern Finland. There were 117 young adults born early preterm (= 37 weeks, controls). Autonomic function was analyzed by calculating time and frequency domain heart rate variability measurements using linear regression. Results Compared with controls, the mean difference in root mean square of successive differences (indicating cardiac vagal activity) was -12.0% (95% CI -22.2%, -0.5%, adjusted for sex, age, source cohort, and season P = .04) for the early preterm group and -7.8% (-16.8%, 2.0%, P = .12) for the late preterm group. Mean differences with controls in low frequency power (indicating cardiac vagal activity, including some sympathetic- and baroreflex-mediated effects) were -13.6% (-26.7%, 1.8%, P = .08) for the early pretermgroup and -16.4% (-27.0%, -4.3%, P = .01) for the late preterm group. Mean differences in high frequency power (quantifying cardiac vagal modulation in respiratory frequency) were -19.2% (-36.6%, 2.9%, P = .09) for the early preterm group and -13.8% (-29.4%, 5.3%, P = .15) for the late preterm group. Differences were attenuated when controlled for body mass index and physical activity. Conclusions Our results suggest altered autonomic regulatory control in adults born preterm, including those born late preterm. Altered autonomic regulatory control may contribute to increased cardiovascular risk in adults born preterm.
  • Ahonen, Lauri; Cowley, Benjamin; Torniainen, Jari; Ukkonen, Antti; Vihavainen, Arto; Puolamäki, Kai (2016)
    It is known that periods of intense social interaction result in shared patterns in collaborators' physiological signals. However, applied quantitative research on collaboration is hindered due to scarcity of objective metrics of teamwork effectiveness. Indeed, especially in the domain of productive, ecologically-valid activity such as programming, there is a lack of evidence for the most effective, affordable and reliable measures of collaboration quality. In this study we investigate synchrony in physiological signals between collaborating computer science students performing pair-programming exercises in a class room environment. We recorded electrocardiography over the course of a 60 minute programming session, using lightweight physiological sensors. We employ correlation of heart-rate variability features to study social psychophysiological compliance of the collaborating students. We found evident physiological compliance in collaborating dyads' heart-rate variability signals. Furthermore, dyads' self-reported workload was associated with the physiological compliance. Our results show viability of a novel approach to field measurement using lightweight devices in an uncontrolled environment, and suggest that self-reported collaboration quality can be assessed via physiological signals.
  • Tuomikoski, Pauliina; Salomaa, Veikko; Havulinna, Aki; Airaksinen, Juhani; Ketonen, Matti; Koukkunen, Heli; Ukkola, Olavi; Kesaniemi, Y. Antero; Lyytinen, Heli; Ylikorkala, Olavi; Mikkola, Tomi S. (2016)
    Objectives: The role of postmenopausal hormone therapy (HT) in the incidence of acute coronary syndrome (ACS) has been studied extensively, but less is known of the impact of HT on the mortality risk due to an ACS. Study design and main outcome measures: We extracted from a population-based ACS register, FINAMI, 7258 postmenopausal women with the first ACS. These data were combined with HT use data from the National Drug Reimbursement Register; 625 patients (9%) had used various HT regimens. The death risks due to ACS before admission to hospital, 2-28, or 29-365 days after the incident ACS were compared between HT users and non-users with logistic regression analyses. Results: In all follow-up time points, the ACS death risks in HT ever-users were smaller compared to non-users. Of women with FIT ever use, 42% died within one year as compared with 52% of non-users (OR 0.62, p <0.001). Most deaths (84%) occurred within 28 days after the ACS, and in this group 36% of women with ever use of FIT (OR 0.73, p = 0.002) and 30% of women with >= 5 year FIT use (OR 0.54, p <0.001) died as compared to 43% of the non-users. Age 60 years at the HT initiation was accompanied with similar reductions in ACS mortality risk. Conclusions: Postmenopausal HT use is accompanied with reduced mortality risk after primary ACS. (C) 2016 Elsevier Ireland Ltd. All rights reserved.
  • Halko, Marja-Liisa; Lappalainen, Olli; Sääksvuori, Lauri (2021)
    We investigate the feasibility of inferring economic choices from simple biometric non-choice data. We employ a machine learning approach to assess whether biometric data acquired during sleep, naturally occurring daily chores and participation in an experi-ment can reveal preferences for competitive and team-based compensation schemes. We find that biometric data acquired using wearable devices enable equally accurate out-of-sample prediction for compensation-scheme choice as gender and performance. Our re-sults demonstrate the feasibility of inferring economic choices from simple biometric data without observing past decisions. However, we find that biometric data recorded in nat-urally occurring environments during daily chores and sleep add little value to out-of-sample predictions. (c) 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )
  • Virtanen, Juhani; Leivo, Joni; Vehkaoja, Antti; Somppi, Sanni; Tornqvist, Heini; Fiedler, Patrique; Vaataja, Heli; Surakka, Veikko (ACM, 2018)
    Measuring the heart rate of animals is an important area of research which can be applied to numerous analyses. In this work we evaluate the performance of two dry contact electrocardiogram (ECG) electrode structures for monitoring the heart rate of domestic pets. The aim was to improve the operation of previously evaluated electrodes with some modifications. First, the thirty-pins of a previously studied polymer electrode with a silver/silver chloride (Ag/AgCl) coating were reduced to 12. Second, a 12-pin gold-plated metal electrode was coated with poly (3,4 ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS). These electrodes were attached to a specifically designed measurement harness and the performance of the electrodes was evaluated in terms of heartbeat detection coverage. The heart rate coverage was measured during four different behaviors: standing, sitting, lying, and walking (N=27/activity). The results were, in general, comparable to the previously reported performance but having fewer pins on a polymer electrode seemed to cause more variation in the coverage values. However, when measures such as the median value of the coverages are considered, there was no obvious difference, especially when the coverage values were observed altogether. Thus, new electrode solutions are worthy of further research.
  • Chumaeva, Nadja; Hintsanen, Mirka; Hintsa, Taina; Ravaja, Niklas; Juonala, Markus; Raitakari, Olli T.; Keltikangas-Järvinen, Liisa (2010)
  • Seppänen, Sirke; Toivanen, Tapio; Makkonen, Tommi; Jääskeläinen, Iiro P; Anttonen, Mikko; Tiippana, Kaisa (2020)
    Objectives Teaching involves multiple performance situations, potentially causing psychosocial stress. Since the theater-based improvisation method is associated with diminished social stress, we investigated whether improvisation lessened student teachers’ stress responses using the Trier Social Stress Test (TSST; preparatory phase, public speech, and math task). Moreover, we studied the influence of interpersonal confidence (IC) – the belief regarding one’s capability related to effective social interactions – on stress responses. Methods The intervention group (n = 19) received a 7-week (17.5 h) improvisation training, preceded and followed by the TSST. We evaluated experienced stress using a self-report scale, while physiological stress was assessed before (silent 30-s waiting period) and during the TSST tasks using cardiovascular measures (heart rate, heart rate variability [HRV]), electrodermal activation, facial electromyography (f-EMG), and EEG asymmetry. Hypothalamus-pituitary-adrenal (HPA-axis) reactivity was assessed through repeated salivary cortisol sampling. Results Compared to the control group (n = 16), the intervention group exhibited less f-EMG activity before a public speech and higher HRV before the math task. The low IC intervention subgroup reported significantly less stress during the math task. The controls showed a decreased heart rate before the math task, and controls with a low IC exhibited higher HRV during the speech. Self-reported stress and cortisol levels were positively correlated during the post-TSST preparatory phase. Conclusions These findings suggest that improvisation training might diminish stress levels, specifically before a performance. In addition, interpersonal confidence appears to reduce stress responses. The decreased stress responses in the control group suggest adaptation through repetition. Keywords: Improvisation; Anticipatory anxiety; Interpersonal confidence; Psychophysiology; Teacher education; Trier Social Stress Test
  • Ylikoski, Jukka; Lehtimaki, Jarmo; Pirvola, Ulla; Makitie, Antti; Aarnisalo, Antti; Hyvarinen, Petteri; Ylikoski, Matti (2017)
    Conclusion: Transcutaneous vagal nerve stimulation (tVNS) might offer a targeted, patient-friendly, and low-cost therapeutic tool for tinnitus patients with sympathovagal imbalance. Objectives: Conventionally, VNS has been performed to treat severe epilepsy and depression with an electrode implanted to the cervical trunk of vagus nerve. This study investigated the acute effects of tVNS on autonomic nervous system (ANS) imbalance, which often occurs in patients with tinnitus-triggered stress. Methods: This study retrospectively analysed records of 97 patients who had undergone ANS function testing by heart rate variability (HRV) measurement immediately before and after a 15-60min tVNS stimulation. Results: The pre-treatment HRV recording showed sympathetic preponderance/reduced parasympathetic activity in about three quarters (73%) of patients. Active tVNS significantly increased variability of R-R intervals in 75% of patients and HRV age was decreased in 70% of patients. Either the variability of R-R intervals was increased or the HRV age decreased in 90% of the patients. These results indicate that tVNS can induce a shift in ANS function from sympathetic preponderance towards parasympathetic predominance. tVNS caused no major morbidity, and heart rate monitoring during the tVNS treatment showed no cardiac or circulatory effects (e.g. bradycardia) in any of the patients.
  • van Leeuwen, Wessel M. A.; Sallinen, Mikael; Virkkala, Jussi; Lindholm, Harri; Hirvonen, Ari; Hublin, Christer; Porkka-Heiskanen, Tarja; Harma, Mikko (2018)
    Purpose Sleep restriction is increasingly common and associated with the development of health problems. We investigated how the neuroendocrine stress systems respond to prolonged sleep restriction and subsequent recovery sleep in healthy young men. Methods After two baseline (BL) nights of 8 h time in bed (TIB), TIB was restricted to 4 h per night for five nights (sleep restriction, SR, n = 15), followed by three recovery nights (REC) of 8 h TIB, representing a busy workweek and a recovery weekend. The control group (n = 8) had 8 h TIB throughout the experiment. A variety of autonomic cardiovascular parameters, together with salivary neuropeptide Y (NPY) and cortisol levels, were assessed. Results In the control group, none of the parameters changed. In the experimental group, heart rate increased from 60 +/- 1.8 beats per minute (bpm) at BL, to 63 +/- 1.1 bpm after SR and further to 65 +/- 1.8 bpm after REC. In addition, whole day low-frequency to-high frequency (LF/HF) power ratio of heart rate variability increased from 4.6 +/- 0.4 at BL to 6.0 +/- 0.6 after SR. Other parameters, including salivary NPY and cortisol levels, remained unaffected. Conclusions Increased heart rate and LF/HF power ratio are early signs of an increased sympathetic activity after prolonged sleep restriction. To reliably interpret the clinical significance of these early signs of physiological stress, a follow-up study would be needed to evaluate if the stress responses escalate and lead to more unfavourable reactions, such as elevated blood pressure and a subsequent elevated risk for cardiovascular health problems.
  • Noerman, Stefania; Klavus, Anton; Järvelä-Reijonen, Elina; Karhunen, Leila; Auriola, Seppo; Korpela, Riitta; Lappalainen, Raimo; Kujala, Urho M.; Puttonen, Sampsa; Kolehmainen, Marjukka; Hanhineva, Kati (2020)
    Psychological stress is a suggested risk factor of metabolic disorders, but molecular mediators are not well understood. We investigated the association between the metabolic profiles of fasting plasma and the improvement of psychological well-being using non-targeted liquid chromatography-mass spectrometry (LC-MS) platform. The metabolic profiles of volunteers participating in the face-to-face intervention group (n = 60) in a randomised lifestyle intervention were compared to ones of controls (n = 64) between baseline and 36-week follow-up. Despite modest differences in metabolic profile between groups, we found associations between phosphatidylcholines (PCs) and several parameters indicating stress, adiposity, relaxation, and recovery. The relief of heart-rate-variability-based stress had positive, while improved indices of recovery and relaxation in the intervention group had an inverse association with the reduction of e.g. lysophosphatidylcholines (LPC). Interleukin-1 receptor antagonist and adiposity correlated positively with the suppressed PCs and negatively with the elevated plasmalogens PC(P-18:0/22:6) and PC(P-18:0/20:4). Also, we found changes in an unknown class of lipids over time regardless of the intervention groups, which also correlated with physiological and psychological markers of stress. The associations between lipid changes with some markers of psychological wellbeing and body composition may suggest the involvement of these lipids in the shared mechanisms between psychological and metabolic health.
  • Järvelä-Reijonen, Elina; Järvinen, Suvi; Karhunen, Leila; Föhr, Tiina; Myllymäki, Tero; Sairanen, Essi; Lindroos, Sanni; Peuhkuri, Katri; Hallikainen, Maarit; Pihlajamäki, Jussi; Puttonen, Sampsa; Korpela, Riitta; Ermes, Miikka; Lappalainen, Raimo; Kujala, Urho M.; Kolehmainen, Marjukka; Laitinen, Jaana (2021)
    Background: Association of physiological recovery with nutrition has scarcely been studied. We investigated whether physiological recovery during sleep relates to eating habits, i.e., eating behaviour and diet quality. Methods: Cross-sectional baseline analysis of psychologically distressed adults with overweight (N = 252) participating in a lifestyle intervention study in three Finnish cities. Recovery measures were based on sleep-time heart rate variability (HRV) measured for 3 consecutive nights. Measures derived from HRV were 1) RMSSD (Root Mean Square of the Successive Differences) indicating the parasympathetic activation of the autonomic nervous system and 2) Stress Balance (SB) indicating the temporal ratio of recovery to stress. Eating behaviour was measured with questionnaires (Intuitive Eating Scale, Three-Factor Eating Questionnaire, Health and Taste Attitude Scales, ecSatter Inventory (TM)). Diet quality was quantified using questionnaires (Index of Diet Quality, Alcohol Use Disorders Identification Test Consumption) and 48-h dietary recall. Results: Participants with best RMSSD reported less intuitive eating (p = 0.019) and less eating for physical rather than emotional reasons (p = 0.010) compared to those with poorest RMSSD; participants with good SB reported less unconditional permission to eat (p = 0.008), higher fibre intake (p = 0.028), higher diet quality (p = 0.001), and lower alcohol consumption (p < 0.001) compared to those with poor SB, although effect sizes were small. In subgroup analyses among participants who reported working regular daytime hours (n = 216), only the associations of SB with diet quality and alcohol consumption remained significant. Conclusions: Better nocturnal recovery showed associations with better diet quality, lower alcohol consumption and possibly lower intuitive eating. In future lifestyle interventions and clinical practice, it is important to acknowledge sleep-time recovery as one possible factor linked with eating habits.
  • Ylikoski, Jukka; Markkanen, Marika; Pirvola, Ulla; Lehtimaki, Jarmo Antero; Ylikoski, Matti; Jing, Zou; Sinkkonen, Saku T.; Mäkitie, Antti (2020)
    Introduction Tinnitus can become a strong stressor for some individuals, leading to imbalance of the autonomous nervous system with reduction of parasympathetic activity. It can manifest itself as sleep disturbances, anxiety and even depression. This condition can be reversed by bioelectrical vagal nerve stimulation (VNS). Conventional invasive VNS is an approved treatment for epilepsy and depression. Transcutaneous VNS (taVNS) stimulating the auricular branch of the vagus nerve has been shown to activate the vagal pathways similarly as an implanted VNS. Therefore, taVNS might also be a therapeutic alternative in health conditions such as tinnitus-related mental stress (TRMS). This retrospective study in 171 TRMS patients reports the clinical features, psychophysiological characteristics, and results of the heart rate variability (HRV) tests before and after test-taVNS. This study also reports the therapy outcomes of 113 TRMS patients treated with taVNS, in combination with standard tinnitus therapy. Methods Diagnostic tinnitus and hearing profiles were defined. To detect possible cardiac adverse effects, test-taVNS with heart rate monitoring as well as pre- and post-stimulation HRV tests were performed. Daily taVNS home therapy was prescribed thereafter. To assess therapeutic usefulness of taVNS, 1-year follow-up outcome was studied. Results of HRV tests were retrospectively analyzed and correlated to diagnostic data. Results The large majority of patients with TRMS suffer from associated symptoms such as sleep disturbances and anxiety. Baseline HRV data showed that more than three quarters of the 171 patients had increased sympathetic activity before test-taVNS. Test-taVNS shifted mean values of different HRV parameters toward increased parasympathetic activity in about 80% of patients. Test-taVNS did not cause any cardiac or other side effects. No significant adverse effects were reported in follow-up questionnaires. Conclusion TRMS is an example of a stress condition in which patients may benefit from taVNS. As revealed by HRV, test-taVNS improved parasympathetic function, most efficiently in patients with a low starting HRV level. Our tinnitus treatment program, including taVNS, effectively alleviated tinnitus stress and handicap. For wider clinical use, there is a great need for more knowledge about the optimal methodology and parameters of taVNS.
  • Saarinen, Aino; Lieslehto, Johannes; Kiviniemi, Vesa; Häkli, Jani; Tuovinen, Timo; Hintsanen, Mirka; Veijola, Juha (2020)
    Background Physiological brain pulsations have been shown to play a critical role in maintaining interstitial homeostasis in the glymphatic brain clearance mechanism. We investigated whether psychotic symptomatology is related to the physiological variation of the human brain using fMRI. Methods The participants (N = 277) were from the Northern Finland Birth Cohort 1986. Psychotic symptoms were evaluated with the Positive Symptoms Scale of the Structured Interview for Prodromal Syndromes (SIPS). We used the coefficient of variation of BOLD signal (CVBOLD) as a proxy for physiological brain pulsatility. The CVBOLD-analyses were controlled for motion, age, sex, and educational level. The results were also compared with fMRI and voxel-based morphometry (VBM) meta-analyses of schizophrenia patients (data from the Brainmap database). Results At the global level, participants with psychotic-like symptoms had higher CVBOLD in cerebrospinal fluid (CSF) and white matter (WM), when compared to participants with no psychotic symptoms. Voxel-wise analyses revealed that CVBOLD was increased, especially in periventricular white matter, basal ganglia, cerebellum and parts of the cortical structures. Those brain regions, which included alterations of physiological fluctuation in symptomatic psychosis risk, overlapped
  • Kuula, Liisa; Halonen, Risto; Kajanto, Kristiina; Lipsanen, Jari; Makkonen, Tommi; Peltonen, Miina; Pesonen, Anu-Katriina (2020)
    Knowledge on efficient ways to reduce presleep arousal and, therefore, improve sleep, is scanty. We explored the effects of presleep slow breathing and music listening conditions on sleep quality and EEG power spectral density in young adults in a randomized, controlled trial with a crossover design. Participants’ (N = 20, 50% females) sleep was measured on two consecutive nights with polysomnography (40 nights), the other night serving as the control condition. The intervention condition was either a 30-minute slow breathing exercise or music listening (music by Max Richter: Sleep). The intervention and control conditions were placed in a random order. We measured heart rate variability prior to, during and after the intervention condition, and found that both interventions increased immediate heart rate variability. Music listening resulted in decreased N2 sleep, increased frontal beta1 power spectral density, and a trend towards increased N3 sleep was detected. In the slow breathing condition higher central delta power during N3 was observed. While some indices pointed to improved sleep quality in both intervention groups, neither condition had robust effects on sleep quality. These explorative findings warrant further replication in different populations.
  • Voikar, Vootele; Gaburro, Stefano (2020)
    Animal models of neurodegenerative and neuropsychiatric disorders require extensive behavioral phenotyping. Currently, this presents several caveats and the most important are: (i) rodents are nocturnal animals, but mostly tested during the light period; (ii) the conventional behavioral experiments take into consideration only a snapshot of a rich behavioral repertoire; and (iii) environmental factors, as well as experimenter influence, are often underestimated. Consequently, serious concerns have been expressed regarding the reproducibility of research findings on the one hand, and appropriate welfare of the animals (based on the principle of 3Rs—reduce, refine and replace) on the other hand. To address these problems and improve behavioral phenotyping in general, several solutions have been proposed and developed. Undisturbed, 24/7 home-cage monitoring (HCM) is gaining increased attention and popularity as demonstrating the potential to substitute or complement the conventional phenotyping methods by providing valuable data for identifying the behavioral patterns that may have been missed otherwise. In this review, we will briefly describe the different technologies used for HCM systems. Thereafter, based on our experience, we will focus on two systems, IntelliCage (NewBehavior AG and TSE-systems) and Digital Ventilated Cage (DVC®, Tecniplast)—how they have been developed and applied during recent years. Additionally, we will touch upon the importance of the environmental/experimenter artifacts and propose alternative suggestions for performing phenotyping experiments based on the published evidence. We will discuss how the integration of telemetry systems for deriving certain physiological parameters can help to complement the description of the animal model to offer better translation to human studies. Ultimately, we will discuss how such HCM data can be statistically interpreted and analyzed.
  • Esposito, Pasquale; Mereu, Roberto; De Barbieri, Giacomo; Rampino, Teresa; Di Toro, Alessandro; Groop, Per-Henrik; Dal Canton, Antonio; Bernardi, Luciano (2016)
    Cardiovascular autonomic dysfunction, evaluated as baroreflex sensitivity (BRS), could be acutely corrected by slow breathing or oxygen administration in patients with type 1 diabetes, thus suggesting a functional component of the disorder. We tested this hypothesis in patients with the type 2 diabetes with or without renal impairment. Twenty-six patients with type 2 diabetes (aged 61.0 +/- A 0.8 years, mean +/- A SEM; duration of diabetes 10.5 +/- A 2 years, BMI 29.9 +/- A 0.7 kg/m(2), GFR 68.1 +/- A 5.6 ml/min) and 24 healthy controls (aged 58.5 +/- A 1.0 years) were studied. BRS was obtained from recordings of RR interval and systolic blood pressure fluctuations during spontaneous and during slow, deep (6 breaths/min) controlled breathing in conditions of normoxia or hyperoxia (5 l/min oxygen). During spontaneous breathing, diabetic patients had lower RR interval and lower BRS compared with the control subjects (7.1 +/- A 1.2 vs. 12.6 +/- A 2.0 ms/mmHg, p <0.025). Deep breathing and oxygen administration significantly increased arterial saturation, reduced RR interval and increased BRS in both groups (to 9.6 +/- A 1.8 and 15.4 +/- A 2.4 ms/mmHg, respectively, p <0.05, hyperoxia vs. normoxia). Twelve diabetic patients affected by chronic diabetic kidney disease (DKD) presented a significant improvement in the BRS during slow breathing and hyperoxia (p <0.025 vs. spontaneous breathing during normoxia). Autonomic dysfunction present in patients with type 2 diabetes can be partially reversed by slow breathing, suggesting a functional role of hypoxia, also in patients with DKD. Interventions known to relieve tissue hypoxia and improve autonomic function, like physical activity, may be useful in the prevention and management of complications in patients with diabetes.