The acute effects of Zone 2 aerobic exercise on Vagus nerve activity and postprandial sleepiness in women
DOI:
https://doi.org/10.47197/retos.v78.118411Keywords:
Zone 2 exercise, Heart rate variability, Vagus nerve, Postprandial somnolence, WomenAbstract
Background: postprandial sleepiness is a common problem in women, characterized by reduced alertness after meals due to autonomic and metabolic shifts toward digestion. Zone 2 aerobic exercise, a moderate-intensity activity focused on fat oxidation, may enhance vagal activity and counteract this postprandial sleepiness.
Objective: This study examined the acute effects of Zone 2 exercise on vagal activity and postprandial sleepiness in women.
Methods: Twenty women aged 30–45 years were randomly assigned to an experimental group (n=10) or a control group (n=10). After consuming a standardized meal, the experimental group performed 40 minutes of treadmill walking at Zone 2 exercise intensity (60–70% of maximum heart rate), while the control group rested passively. Vagal activity was assessed using heart rate variability (rMSSD values), and sleepiness was measured with the Stanford Sleepiness Scale. Paired and independent t-tests were used for analysis, with effect sizes calculated.
Results: The experimental group showed significant improvements, with increased rMSSD values and reduced sleepiness, whereas the control group demonstrated decreased vagal activity and increased sleepiness. Between-group post-test differences were statistically significant with large effect sizes.
Conclusion: Zone 2 exercise effectively enhances vagal tone and reduces postprandial sleepiness. It represents a practical, non-pharmacological strategy to improve alertness and autonomic balance in women.
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