Reduced heart rate variability during sleep in long-duration spaceflight

2013 ◽  
Vol 305 (2) ◽  
pp. R164-R170 ◽  
Author(s):  
D. Xu ◽  
J. K. Shoemaker ◽  
A. P. Blaber ◽  
P. Arbeille ◽  
K. Fraser ◽  
...  

Limited data are available to describe the regulation of heart rate (HR) during sleep in spaceflight. Sleep provides a stable supine baseline during preflight Earth recordings for comparison of heart rate variability (HRV) over a wide range of frequencies using both linear, complexity, and fractal indicators. The current study investigated the effect of long-duration spaceflight on HR and HRV during sleep in seven astronauts aboard the International Space Station up to 6 mo. Measurements included electrocardiographic waveforms from Holter monitors and simultaneous movement records from accelerometers before, during, and after the flights. HR was unchanged inflight and elevated postflight [59.6 ± 8.9 beats per minute (bpm) compared with preflight 53.3 ± 7.3 bpm; P < 0.01]. Compared with preflight data, HRV indicators from both time domain and power spectral analysis methods were diminished inflight from ultralow to high frequencies and partially recovered to preflight levels after landing. During inflight and at postflight, complexity and fractal properties of HR were not different from preflight properties. Slow fluctuations (<0.04 Hz) in HR presented moderate correlations with movements during sleep, partially accounting for the reduction in HRV. In summary, substantial reduction in HRV was observed with linear, but not with complexity and fractal, methods of analysis. These results suggest that periodic elements that influence regulation of HR through reflex mechanisms are altered during sleep in spaceflight but that underlying system complexity and fractal dynamics were not altered.

2001 ◽  
Vol 179 (2) ◽  
pp. 167-171 ◽  
Author(s):  
Hagit Cohen ◽  
Uri Loewenthal ◽  
Michael Matar ◽  
Moshe Kotler

BackgroundAntipsychotic medications cause a wide range of adverse effects and have been associated with sudden death in psychiatric patients.AimsTo supply power spectral analysis of heart rate variability as a tool to examine the arrythmogenic effects of neuroleptics.MethodHeart rate analysis was carried out in patients with schizophrenia on standard doses of neuroleptic monotherapy − 21 were on clozapine, 18 on haloperidol and 17 on olanzapine – and in 53 healthy subjects.ResultsPatients with schizophrenia on clozapine had significantly higher heart rate, lower heart rate variability and lower high-frequency and higher low-frequency components compared with patients on haloperidol or olanzapine and matched control subjects. Prolonged QTc intervals were more common in patients than controls.ConclusionsPatients treated with neuroleptic medications, especially clozapine, showed autonomic dysregulation and cardiac repolarisation changes. Physicians should be aware of this adverse reaction.


2007 ◽  
Vol 25 (11) ◽  
pp. 2280-2285 ◽  
Author(s):  
Robert H Fagard ◽  
Katarzyna Stolarz ◽  
Tatiana Kuznetsova ◽  
Jitka Seidlerova ◽  
Valérie Tikhonoff ◽  
...  

2014 ◽  
Vol 30 (1) ◽  
pp. 11-15
Author(s):  
Qazi Farzana Akhter ◽  
Qazi Shamima Akhter ◽  
Farhana Rahman ◽  
Sybyla Ferdousi ◽  
Susmita Sinha

Heart rate variability (HRV) has been considered as an indicator of autonomic nerve function status. We aimed to find out the reference values of heart rate variability by power spectral analysis in our healthy population of different age. This cross sectional study was conducted in the Department of Physiology, Dhaka Medical College, Dhaka from the period of July 2012 to June 2013. For this, 180 subjects were selected with the age ranging from 15-60 years. All the study subjects were divided into 3 different groups according to age (Group A: 15-30 years; Group B: 31-45 years; Group C: 46-60 years). Each group contained 60 subjects of which 30 were male and 30 were female. The subjects were selected from different areas of Dhaka city by personal contacts. Analysis of HRV parameters were done in Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka. For statistical analysis, one way ANOVA, unpaired Students t-test and Pearson’s correlation coefficient test were performed by using SPSS (version-17) as applicable. LF nu, LF power and LF/HF were significantly (p<0.001) higher in group C in comparison to those of group A and B. Again Total power, HF power, HF nu (p<0.001) were significantly higher in group A and B in comparison to that of group C. This study concludes that cardiac parasympathetic activity was decreased and sympathetic activity was increased with aging.DOI: http://dx.doi.org/10.3329/bjpp.v30i1.20788 Bangladesh J Physiol Pharmacol 2014; 30(1):11-15


1998 ◽  
Vol 275 (1) ◽  
pp. H213-H219 ◽  
Author(s):  
Michael V. Højgaard ◽  
Niels-Henrik Holstein-Rathlou ◽  
Erik Agner ◽  
Jørgen K. Kanters

Frequency domain analysis of heart rate variability (HRV) has been proposed as a semiquantitative method for assessing activities in the autonomic nervous system. We examined whether absolute powers, normalized powers, and the low frequency-to-high frequency ratio (LF/HF) derived from the HRV power spectrum could detect shifts in autonomic balance in a setting with low sympathetic nervous tone. Healthy subjects were examined for 3 h in the supine position during 1) control conditions ( n = 12), 2) acute β-blockade ( n = 11), and 3) chronic β-blockade ( n = 10). Heart rate fell during the first 40 min of the control session (72 ± 2 to 64 ± 2 beats/min; P < 0.005) and was even lower during acute and chronic β-blockade (56 ± 2 beats/min; P < 0.005). The powers of all spectral areas rose during the first 60 min in all three settings, more so with β-blockade ( P < 0.05). LF/HF was found to contain the same information as powers expressed in normalized units. LF/HF detected the shift in autonomic balance induced by β-blockade but not the change induced by supine position. In conclusion, none of the investigated measures derived from power spectral analysis comprehensively and consistently described the changes in autonomic balance.


1996 ◽  
Vol 19 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Tadashi Aono ◽  
Takayuki Sato ◽  
Masanori Nishinaga ◽  
Akiko Kawamoto ◽  
Toshio Ozawa

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