September 1, 2004Journal of Investigative Medicine
Parasympathetic Effects on Heart Rate Recovery after Exercise
Key result
Atropine administration during high-intensity exercise revealed a persistent parasympathetic effect on heart rate during maximal exercise (3.4-6 bpm, p<0.05) and early recovery (22.8 bpm, p<0.0002).
Why the study?
Does parasympathetic blockade with atropine alter heart rate recovery after high-intensity exercise in normal subjects?
Population
10 normal subjects (five women; age 33 +/- 2 years)
Comparison
Atropine administered 1 minute into the maximum… vs Identical exercise protocol performed on day 1…
Design
Other
Follow-up
10 minutes of recovery
Authors
Discussion
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Member takes
Implication
May support parasympathetic protection in early recovery; leaves open clinical relevance for arrhythmia prevention pending larger studies.
Key Points
- This research aims to explore the effects of parasympathetic activity on heart rate during high-intensity exercise and its recovery phase.
- Ten normal subjects underwent two exercise sessions on a bicycle ergometer.
- Atropine was administered during the maximum exercise stage on day two.
- Heart rates were recorded at various intervals during and after exercise.
- The parasympathetic effect during maximal exercise was 3.4 to 6 bpm (p < .05).
- In recovery, there was a significant parasympathetic effect on heart rate at one minute (22.8 bpm; p < .0002).
- P-R interval was shorter during recovery with parasympathetic blockade (p < .002).
Structured PICO
Does parasympathetic blockade with atropine alter heart rate recovery after high-intensity exercise in normal subjects?
P
Population
10 normal subjects (50% female, mean age 33 years) undergoing exercise testing to evaluate parasympathetic effects during high-intensity exercise and recovery.
I
Intervention
Atropine (0.04 mg/kg) administered 1 minute into the maximum exercise stage on day 2
C
Comparator
Identical exercise protocol performed on day 1 without atropine
O
Outcome
Parasympathetic effect on heart rate (defined by the difference in heart rate with and without atropine) during exercise and recoverysurrogate
Main Result
Mean Difference: 22.8
p-value: p=< .0002
Parasympathetic effects persist during high-intensity exercise and are prominent in early recovery, suggesting a protective role against sudden cardiac death during these periods.
Cite This Study
Kannankeril et al. (2004) studied Normal subjects (n=10). Atropine vs. No atropine (day 1 baseline) was evaluated on Parasympathetic effect on heart rate (difference in heart rate with and without atropine) at 1 minute of recovery (MD 22.8 bpm, p=< .0002). Atropine administration during high-intensity exercise revealed a persistent parasympathetic effect on heart rate during maximal exercise (3.4-6 bpm, p<0.05) and early recovery (22.8 bpm, p<0.0002).