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The effect of meal size on the cardiovascular responses to food ingestion
1Department of Physiology and Pharmacology, University of Nottingham Medical School.
Insights
Ingesting high-carbohydrate meals significantly increases heart rate and cardiac output in healthy females. Larger meals result in greater cardiovascular responses, affecting blood flow distribution.
Area of Science:
- Cardiovascular physiology
- Human nutrition
- Metabolic studies
Background:
- Postprandial cardiovascular adjustments are crucial for nutrient delivery.
- The impact of meal size on central and peripheral hemodynamics requires further investigation.
Purpose of the Study:
- To investigate the effects of varying high-carbohydrate meal sizes on cardiovascular function.
- To determine the relationship between meal energy content and hemodynamic responses.
Main Methods:
- Eight healthy females consumed 1, 2, or 3 MJ high-carbohydrate meals.
- Measurements included cardiac output (indirect Fick), blood pressure, heart rate (oscillometry), superior mesenteric artery blood flow (Duplex Doppler), and calf blood flow (venous occlusion plethysmography).
- Hemodynamic parameters were recorded in a fasted state and for 120 minutes postprandially.
Main Results:
- Heart rate and cardiac output significantly increased after all meal sizes.
- Larger meals (3 MJ) elicited greater integrated cardiac output increments compared to smaller meals.
- Superior mesenteric artery blood flow increased significantly with all meals, with larger meals showing a more pronounced and sustained increase.
- Calf blood flow transiently decreased after the largest meal.
Conclusions:
- High-carbohydrate meals induce significant central and peripheral cardiovascular adaptations.
- A dose-dependent relationship exists between meal size and the magnitude of postprandial cardiovascular responses.
- These findings highlight the substantial hemodynamic changes associated with food intake and meal energy content.
Abstract:
Cardiac output (CO; indirect Fick), blood pressure (BP) and heart rate (HR; oscillometry), superior mesenteric artery blood flow (SMABF; Duplex Doppler) and calf blood flow (CBF; venous occlusion plethysmography) were recorded in the fasted state and for 120 min following the ingestion of 1, 2, and 3 MJ, high-carbohydrate meals in eight healthy females. BP was unchanged following food. HR (P < 0.0005) and CO (P < 0.005) rose significantly following all three meals. Integrated increments in CO over the postprandial period were greater after 3 MJ compared with the 1 and 2 MJ meals (P < 0.05). SMABF rose significantly following all three meals. The pattern of blood flow response was significantly different between the 1 and 3 MJ meals (interaction effect P < 0.02, ANOVA), with blood flow after the 3 MJ meal being significantly greater than flow after the 1 MJ meal at 15, 60, and 90 min. Similarly, the pattern of response was significantly different after the 2 and 3 MJ meals (interaction effect P < 0.03, ANOVA), with blood flow being significantly greater at 15 and 90 min after the 3 MJ meal. CBF fell significantly in the first 15 min after the 3 MJ meal and then recovered towards baseline values. No other significant changes in CBF were recorded. There are substantial peripheral and central cardiovascular changes after food in man and there appears to be a relationship between meal size and the extent of these changes.