A Personalized Low Intensity Exercise Prescription based on an Index of Non-Linear Heart Rate Variability: A Case Report

The short-term scaling exponent alpha1 of detrended fluctuation analysis (DFA a1), a nonlinear index of heart rate variability (HRV) based on fractal correlation properties, has been shown to steadily change with increasing exercise intensity. To date, no study has specifically examined using the behavior of this index as a method for defining a low intensity exercise zone. The aim of this report is to compare both oxygen intake (VO2) and heart rate (HR) reached at the first ventilatory threshold (VT1), a well-established delimiter of low intensity exercise, to those derived from a predefined DFA a1 transitional value. Gas exchange and HRV data were obtained from 15 participants during an incremental treadmill run. Comparison of both VO2 and HR reached at VT1 defined by gas exchange (VT1 GAS) was made to those parameters derived from analysis of DFA a1 reaching a value of 0.75 (HRVT). Based on Bland Altman analysis, linear regression, intraclass correlation (ICC) and t testing, there was strong agreement between VT1 GAS and HRVT as measured by both HR and VO2. Mean VT1 GAS was reached at 39.8 ml/kg/min with a HR of 152 bpm compared to mean HRVT which was reached at 40.1 ml/kg/min with a HR of 154 bpm. Strong linear relationships were seen between test modalities, with Pearson’s r values of 0.99 (p < 0.001) and.97 (p < 0.001) for VO2 and HR comparisons, respectively. Intraclass correlation between VT1 GAS and HRVT was 0.99 for VO2 and 0.96 for HR. In addition, comparison of VT1 GAS and HRVT showed no differences by t testing, also supporting the method validity. In conclusion, it appears that reaching a DFA a1 value of 0.75 on an incremental treadmill test is closely associated with crossing the first ventilatory threshold. As training intensity below the first ventilatory threshold is felt to have great importance for endurance sport, utilization of DFA a1 activity may provide guidance for a valid low training zone.

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Heart rate variability following coronary artery bypass graft surgery as a function of recovery time, posture, and exercise

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y04-076 ◽

2004 ◽

Vol 82 (7) ◽

pp. 457-464 ◽

Cited By ~ 13

Author(s):

C Ann Brown ◽

Larry A Wolfe ◽

Sylvia Hains ◽

Glorianne Ropchan ◽

Joel Parlow

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Baroreflex Sensitivity ◽

Artery Bypass ◽

Bypass Graft ◽

Interval Data ◽

Artery Bypass Graft ◽

Low Intensity ◽

Spontaneous Baroreflex ◽

Low Intensity Exercise

This study examined the claim made by Niemela et al. (1992) that the decline in heart rate variability after coronary artery bypass graft surgery is irreversible. We tested six women and 16 men six and 12 weeks postoperative in three postures: in the supine position, in the standing position, and during low-intensity steady-state exercise. Beat-by-beat arterial blood pressure and electrocardiographic R–R interval data were collected continuously for 10 min in each condition. R–R interval data were analyzed with spectral analysis; baroreflex data were analyzed using the sequence method. Our results show that the indices of parasympathetic modulation improved over time, as seen by an | increased spontaneous baroreflex sensitivity and parasympathetic indicator, that both indices were affected by posture, and that spontaneous baroreflex sensitivity was also affected by low-intensity exercise. The effects of posture are consistent with attenuated responses of healthy older subjects to orthostatic stress. Similarly, the effects of low-intensity exercise are consistent with findings in healthy subjects. We found that spontaneous baroreflex sensitivity declined during exercise, whereas, in healthy subjects, this is maintained during low-intensity steady-state exercise. Our results of significant functional recovery between six and 12 weeks postoperative suggest that at least some of the autonomic dysfunction following surgery is temporary. Previously, no such duration of study has lasted longer than four or six weeks following cardiac surgery, which may not have been long enough to show significant functional restoration in heart rate variability.Key words: heart rate variability, spontaneous baroreflex sensitivity, CABG surgery, posture, exercise.

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Cardiac autonomic modulation in juvenile idiopathic arthritis with use of biological medication: case report

Journal of Human Growth and Development ◽

10.7322/jhgd.v30.9962 ◽

2020 ◽

Vol 30 (1) ◽

pp. 129-134

Author(s):

Patrícia Merly Martinelli ◽

Ana Carolina Gonçalves de Abreu ◽

José Rener Cordeiro da Silva ◽

Asami Takahara Vasconscelos ◽

Adilson Monteiro ◽

...

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Juvenile Idiopathic Arthritis ◽

Case Report ◽

Joint Damage ◽

Response To Therapy ◽

Functional Evaluation ◽

Autonomic Modulation ◽

Cardiac Autonomic Modulation ◽

Non Linear

Introduction: The introduction of biological medication in Juvenile Idiopathic Arthritis (JIA) proposes better therapeutic results with decreased pain and inflammation and consequent reduction in joint damage. The autonomic state can be a predictor for verifying the response to immunomodulation therapy. Thus, measuring heart rate variability can express autonomous behavior and possibly accompany the response to therapy through the expression of the inflammatory condition. Objective: Analysis of heart rate variability in a child with Juvenile Idiopathic Arthritis using the anti-Tumor Necrosis Factor. Methods: This is a clinical case report of an 8-year-old male with a diagnosis of JIA - oligoarticular form, using etanercept, admitted to Clínica Escola de Fisioterapia UNINORTE, Acre, Brazil in 2017. We analyzed laboratory and imaging tests, kinetic-functional evaluation, examination of cardiac autonomic modulation and physiotherapeutic treatment for analgesic, anti-inflammatory purposes, gaining flexibility, strength and postural re-education, according to CARE guidelines, case report guidelines. Results: After medication administration, there was a decrease in pain and normalization of serum creatinine (0.50 mg / dL) and CRP (less than 6 mg / dL) and an increase in erythrocyte sedimentation rate (17 mm3). In the examination of heart rate variability, the linear indices in the time domain showed a predominance of parasympathetic activity (RMSSD: 35ms), with decreased sympathetic control measured through the frequency domain (LF: 27.1 un). However, non-linear methods showed low variability with little dispersion of RR intervals. Conclusion: In the present report, the linear indices showed parasympathetic predominance and in the non-linear analysis a low heart rate variability with abnormal and insufficient adaptation of the autonomic nervous system in a child with juvenile idiopathic arthritis using biological medication.

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