Deep breathing improves blunted baroreflex sensitivity even after 30 years of type 1 diabetes

Abstract

Aims/hypotheses Cardiovascular autonomic neuropathy is associated with increased morbidity in patients with type 1 diabetes. Although it is conventionally considered to be an organic, irreversible disorder, we previously demonstrated in patients with short-duration type 1 diabetes that reduced baroreflex sensitivity (BRS) could be corrected by slow, deep breathing, indicating a functional component to the disorder. We have now tested whether autonomic abnormalities in long-term diabetes progress to a stage that cannot be modified by functional manoeuvres, indicating a switch towards predominantly organic dysfunction. Methods We studied 117 patients with a short duration (8.9± 0.1 years) and 37 patients with a long duration (33.7± 0.5 years) of type 1 diabetes, 73 healthy controls and 12 hearttransplanted participants (surgical heart denervation). An autonomic score was calculated from autonomic function tests. Spectral analysis of heart rate and blood pressure variability, and BRS, were obtained from recordings during normal (15 breaths per min) and slow, deep (six breaths per min) controlled breathing. Results BRS was reduced in all patients, but more in patients with a long duration of diabetes or with increasing autonomic involvement, although the effect of duration disappeared after adjustment for age. Slow breathing increased the BRS to the level of the control participants at a normal rate of breathing (15 per min) in all patients except those with an abnormal autonomic score. Conclusions/interpretation Patients with type 1 diabetes have a blunted BRS that in the majority of patients can be restored by slow breathing, irrespective of disease duration. Even after a long duration of diabetes, the abnormal BRS is at least in part of functional origin.

Baroreflex Sensitivity and Its Response to Deep Breathing Predict Increase in Blood Pressure in Type 1 Diabetes in a 5-Year Follow-Up

“…The potential reversibility of BRS and low prevalence of definite CAN in our patients (3,4) is in line with observations that the prevalence of diabetes complications seems to decrease (5,6). The concept of functional autonomic dysfunction does not diminish the importance of an early diagnosis given that the prognostic value of reduced BRS has undoubtedly been proven in hypertension, renal failure, postmyocardial infarction, heart failure, and cerebral stroke (7–9)—conditions associated with functional alterations in the autonomic nervous system.…”

“…The importance of early diagnosis lies in the fact that established CAN is associated with increased risk of diabetes complications (1) and mortality (2). However, in our recent studies in patients with type 1 diabetes with short (3) or long (4) duration, we demonstrated that reduced baroreflex sensitivity (BRS), an early marker of autonomic impairment, was markedly improved by slow, deep breathing. Notably, the patients had, regardless of duration of diabetes, blunted BRS that could be restored by deep breathing, except in those with definite CAN.…”

Effects of breathing frequency on baroreflex effectiveness index and spontaneous baroreflex sensitivity derived by sequence analysis

“…elderly, hypertensive or diabetic patients). However, the enhancement of baroreflex sensitivity during 0.1 Hz breathing was also found in patients with diabetes [25] or chronic obstructive pulmonary disease [26]. In the setting of paced breathing, we used the same inspiration and expiration times to provide equal opportunity for the occurrence of up and down sequences.…”

Baroreceptor sensitivity and diabetes mellitus

“…Regular exercise has been shown to improve HRV parameters in patients with CAN (Table 4) with a deterioration of those parameters within weeks of complete exercise withdrawal [109]. [90] also appears to be useful in improving BRS in DM patients regardless of the duration (except of course in those with marked CAN). Alpha-lipoic acid (ALA) shows promise in potentially improving BRS in diabetic patients due to the results already obtained in experimental models [86].…”