title: Long-term effects of frequent maximal breath-holding on the cardiac health of elite freedivers.
abstract: Cardiac arrhythmias are commonly reported in freedivers during maximal voluntary breath-holds, but their influence on the cardiological status and their long-term effects on the cardiac health of these athletes have not been investigated. Here we present the results of a study on 32 healthy young men (mean age 32.6 ± 1.3 years) who were divided into two groups of 16 subjects. One group included 16 continuously training freedivers at the "high achievers in sports" level (DIVERS group). The CONTROL group included 16 healthy young men not involved in sports. The subjects were monitored using 24-h electrocardiogram (ECG), and echocardiological study (EchoCG) for all the subjects was performed. The mean heart rate in the DIVERS group was 69.5 ± 1.7 bpm compared with 70.9 ± 1.5 bpm in the CONTROL group. The minimal heart rate was 42.3 ± 1.0 bpm in the DIVERS group and 48.8 ± 1.7 bpm in the CONTROL group (P < 0.005). The maximal heart rate was 132.8 ± 4.6 bpm in the DIVERS group and 132.1 ± 2.9 bpm in the CONTROL group. ECG analysis revealed supraventricular arrhythmias in the DIVERS group: four of the DIVERS (25%) exhibited supraventricular couplets and triplets, three (19%) exhibited transient first- and second-degree AV blocks (Mobitz type 1) at night, and one (6%) exhibited a second-degree sinoatrial block at night. According to the echocardiogram, the DIVERS had slightly larger left ventricles (5.1 ± 1.33, P < 0.05) and left atriums (41.1 ± 12.7) compared with the CONTROL group without exceeding the normal values. The right ventricle volume (3.6 ± 0.69, P < 0.05) was somewhat above the upper normal value (up to 3.5 cm). In conclusion, freediving athletes exhibited changes in their cardiac status, most likely due to the regular exercise, that were not associated with regular maximal voluntary breath-holds. These changes are within the normal physiological values and do not limit their freediving practice.
authors.affiliation: Russian Olympic Committee Innovation Center, Moscow, Russia. iz@i1.ru.
authors.forename: I
authors.initials: I
authors.lastname: Zelenkova
authors.affiliation: Department of Cardiology, I.M. Sechenov First Moscow State Medical University, Moscow, Russia.
authors.forename: P
authors.initials: P
authors.lastname: Chomahidze
mesh_terms: D000328:Adult; D001145:Arrhythmias, Cardiac / Q000453:epidemiology / Q000503:physiopathology*; D054537:Atrioventricular Block / Q000453:epidemiology / Q000503:physiopathology; D062485:Breath Holding; D016022:Case-Control Studies; D004242:Diving; D004452:Echocardiography; D004562:Electrocardiography; D015716:Electrocardiography, Ambulatory; D006321:Heart / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006325:Heart Atria / Q000000981:diagnostic imaging / Q000503:physiopathology; D006339:Heart Rate; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D008297:Male; D012848:Sinoatrial Block / Q000453:epidemiology / Q000503:physiopathology
keywords: Breath-holding; Holter monitoring; echocardiogram; electrocardiogram; long-term effect