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- Title
Effects of caffeine on linear and nonlinear measures of heart rate variability before and after exercise.
- Authors
Yeragani, Vikram K.; Krishnan, Siddartha; Engels, Hermann J.; Gretebeck, Randall
- Abstract
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.
- Subjects
PHYSIOLOGICAL effects of caffeine; HEART beat; VARIABILITY (Psychometrics); EXERCISE; PLACEBOS
- Publication
Depression & Anxiety (1091-4269), 2005, Vol 21, Issue 3, p130
- ISSN
1091-4269
- Publication type
Article
- DOI
10.1002/da.20061