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Effects of caffeine on linear and nonlinear measures of heart rate variability before and after exercise
Author(s) -
Yeragani Vikram K.,
Krishnan Siddartha,
Engels Hermann J.,
Gretebeck Randall
Publication year - 2005
Publication title -
depression and anxiety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.634
H-Index - 129
eISSN - 1520-6394
pISSN - 1091-4269
DOI - 10.1002/da.20061
Subject(s) - caffeine , placebo , heart rate , heart rate variability , medicine , anxiety , approximate entropy , cardiology , anesthesia , physical therapy , psychology , blood pressure , psychiatry , alternative medicine , pathology , pattern recognition (psychology) , cognitive psychology
Caffeine intake is associated with an increase in heart rate (HR) variability. This study sought to examine the effects of caffeine on HR variability measures before and during progressive exercise in 11 healthy volunteers in a double‐blind randomized and counterbalanced placebo‐controlled paradigm. As expected, there were significant increases in HR and decreases in HR variability after exercise during both placebo and caffeine conditions; however, pre‐exercise caffeine condition was associated with a significant increase of HR variability, especially in the high‐frequency range (0.15–0.5 Hz), and also approximate entropy (APEN), which is usually attributed to cardiac vagal function. But during progressive exercise, caffeine intake resulted in a greater decrease of HF power as well as HR APEN. Caffeine also was associated with significantly higher LF power during exercise compared to the placebo condition. These results suggest that caffeine may have different effects on HR variability at rest, compared to exercise. These findings may have implications for patients with cardiac illness and anxiety, depression, and psychotic disorders who use beverages containing excessive caffeine. © 2005 Wiley‐Liss, Inc.