Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Scaling graphs of heart rate time series in athletes demonstrate the
  VLF, LF and HF regions   Scaling analysis of heart rate time series has emerged as an useful tool for
assessment of autonomic cardiac control. We investigate the heart rate time
series of ten athletes (five males and five females), by applying detrended
fluctuation analysis (DFA). High resolution ECGs are recorded under
standardized resting conditions over 30 minutes and subsequently heart rate
time series are extracted and artefacts filtered. We find three distinct
regions of scale-invariance, which correspond to the well-known VLF, LF, and HF
bands in the power spectra of heart rate variability. The scaling exponents
alpha are alphaHF: 1.15 [0.96-1.22], alphaLF: 0.68 [0.57-0.84], alphaVLF:
0.83[0.82-0.99]; p<10^-5). In conclusion, DFA scaling exponents of heart rate
time series should be fitted to the VLF, LF, and HF ranges, respectively.

12
The categories of this paper are: nucl-th
29
The categories of this paper are: funct-an
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The categories of this paper are: eess
8
The categories of this paper are: hep-ex
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The categories of this paper are: q-fin
6
The categories of this paper are: astro-ph
4
The categories of this paper are: cond-mat
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
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The categories of this paper are: bayes-an
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The categories of this paper are: solv-int
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: atom-ph