P5.08 ACUTE CHANGES IN CAROTID DIAMETER AND THICKNESS AFTER AND IRONMAN COMPETITION

Abstract

Objective: The aim of this study was to evaluate the acute effects of participation in Ironman triathlon competition on carotid properties, in relation to hemodynamic load. Methods: 28 male triathletes (41±8 years), participating at the Ironman competition (swimming 3.8 km, cycling 180 km, running 42,2 km; 13 athletes performed half-race), underwent carotid and cardiac ultrasound examinations at rest and within 20’ from the arrival. Right carotid diameter (D), distension (ΔD) and Intima-Media-Thickness (IMT) were estimated by an automatic system applied to ultrasound B-mode image sequences, and carotid pulse pressure (PP) by tonometry. Results: The mean duration of the competition was 12:48±1:14 h (6:14 ± 0:37 hrs for the half-race). At the end of the competition the athletes showed increased heart rate (60.2±13.1 to 82.8±15.6 bpm, p<0.0001), unchanged mean BP (93±14 to 91±10 mmHg, p=ns), carotid PP (from 42 to 42 mmHg, p=ns), and stroke volume (64±14 to 59±16 ml, p=ns) and total body water (48.0±4.0 to 46.5±3.9 kg, p=ns). Cardiac output was significantly increased (5.5±1.2 to 6.7±2.4 l/min, p<0.05), and total peripheral resistances were reduced (17.6±3.9 to 14.8±4.6, p=0.01). D was increased (7.19±0.65 to 7.61 ± 0.76mm, p<0.05), while IMT was significantly reduced at the end of the competition (537±70 to 495±70 μm, p<0.05). ΔD and CC were not modified (588±139 to 568±168 μm and 1.12±0.58 to 1.22±0.54 mm^2/KPa, p=ns). Conclusions: In an Ironman competition, strenuous exercise induced a marked carotid dilation and a decrease in IMT.