Effects of carbohydrate and protein meals on cardiovascular levels and reactivity.

This study examined the effects of standard laboratory stressors on cardiovascular measures before and after the consumption of a modest meal. A mental arithmetic task and a reaction time task were administered before and 2 h after a carbohydrate or a protein meal. A noncaloric placebo meal and a fasting condition were included as control treatments. The caloric meals, in particular the carbohydrate meal, induced an increase in cardiac output, ventricular contractility, and systolic blood pressure. Total peripheral resistance and diastolic blood pressure dropped. Although postprandial adjustments were substantial, stress reactivity patterns generally were not perturbed by the meals. Only heart rate reactivity was stronger after eating the carbohydrate meal. It is concluded that subjects' meal consumption prior to their participation in a psychophysiological experiment needs to be taken into account.