Fig. 2: Illustration of the functional evaluation.

After a 2-day prescribed, weight-maintenance diet, 12 participants were studied on 3 occasions, according to a randomized, crossover design. Briefly, after an overnight fast, the functional evaluation started with a 90-min resting period. It was followed by a 30-min mental stress (consisting of 5-min periods of Stroop’s color word conflict test alternated with 5-min periods of complex mental arithmetic operations), a 30-min recovery period and a 3-min CPT. From time 60, and every 15 min until the end of the test, participants ingested 25-mL test drinks containing either pure water, 106 g.L⁻¹ sucrose or a mix of NNS (392 mg.L⁻¹ sodium cyclamate, 181 mg.L⁻¹ acesulfame K and 116 mg.L⁻¹ aspartame) after a 10-s mouth rinse. The effects of test drinks on hemodynamic stress responses were investigated by the repeated measurement of mean arterial pressure, as well as the continuous monitoring of cardiac output by thoracic electrical bioimpedance measurement. Each functional evaluation was separated by 1–3-week washout periods. CPT: cold pressure test.