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document
Age and autonomic effects on interrelationships between lung volume and heart rate . To determine effects of aging and autonomic input on interrelationships between respiratory and heart rate variability , we collected 5 min of lung volume of R-R interval data from 7 young [ 27 +/- 3 ( SD ) yr ] and 10 older ( 69 +/- 6 yr ) healthy supine humans before and after double pharmacological autonomic blockade with propranolol ( 0.2 mg/kg iv ) and atropine ( 0.04 mg/kg iv ) . Estimates of respiratory and heart rate power spectra and linear transfer functions between the two groups were generated by Fourier analysis . Age , double blockade effects , the age-drug interactions were determined by analysis of variance for repeated measures . Basal R-R intervals were unaffected by age . Double blockade decreased R-R intervals and variability in both age groups ( P < 0.0001 ) , but R-R intervals decreased less in older than in young subjects ( P < 0.0001 ) . In contrast , basal respiratory intervals and standard deviation were greater in older subjects ( P = 0.05 ) and were unaffected by double blockade in young and older subjects . Lung volume-to-heart rate spectral coherence was highest at frequencies associated with respiration and greater in young than in older subjects ( P < 0.07 ) . Double blockade decreased lung volume-to-heart rate variability transfer function magnitude ( P < 0.007 ) and increased phase angle ( P < 0.02 ) without age effects or age-drug interactions . In conclusion , heart rate , respiration , and respiration-heart rate interrelations are altered by aging , and double autonomic pharmacological blockade does not eliminate all age-related differences .
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Intervention_Pharmacological
propranolol
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Intervention_Pharmacological
atropine
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Outcome_Physical
R-R intervals
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Outcome_Physical
variability
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Outcome_Physical
basal respiratory intervals
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Outcome_Physical
Lung volume-to-heart rate spectral coherence
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Outcome_Physical
lung volume-to-heart rate variability transfer function magnitude
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Outcome_Physical
phase angle
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Outcome_Physical
heart rate
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Outcome_Physical
respiration
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Outcome_Physical
respiration-heart rate interrelations
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Participant_Sample-size
7
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Participant_Age
young [ 27 +/- 3 ( SD ) yr ]
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Participant_Sample-size
10
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Participant_Age
older ( 69 +/- 6 yr )
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Participant_Condition
healthy supine humans before and after double pharmacological autonomic blockade with propranolol ( 0.2 mg/kg iv ) and atropine ( 0.04 mg/kg
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Participant_Age
young and older subjects .