To evaluate the effect of a solo ultraendurance open-water swim on autonomic and nonautonomic control of heart rate (HR).
A male athlete (age 48 y, height 172 cm, body mass 68 kg, BMI 23 kg/m2) underwent HR-variability (HRV) and circulating catecholamine evaluations at different times before and after an ultraendurance swim crossing the Adriatic Sea from Italy to Albania. HRV was measured in 5-min segments and quantified by time and frequency domain. Circulating catecholamines were estimated by salivary alpha-amylase (sAA) assay.
The athlete completed 78.1 km in 23:44 h:min. After arrival, sAA levels had increased by 102.6%. Time- and frequency-domain HRV indexes decreased, as well (mean RR interval, −29,7%; standard deviation of normal mean RR interval, −63,1%; square root of mean squared successive differences between normal-to-normal RR intervals, −49.3%; total power, −74.3%; low frequency, −78.0%; high frequency, −76.4%), while HR increased by 41.8%. At 16-h recovery, sAA had returned to preevent values, while a stable tachycardia was accompanied by reduced HRV measures.
To the authors’ knowledge, this is the first study reporting cardiac autonomic adjustments to an extreme and challenging ultraendurance open-water swim. The findings confirmed that the autonomic drives depend on exercise efforts. Since HRV changes did not mirror the catecholamine response 16 h postevent, the authors assume that the ultraendurance swim differently influenced cardiac function by both adaptive autonomic and nonautonomic patterns.
Valenzano, Moscatelli, Triggiani, and Cibelli are with the Dept of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy. Capranica, De Ioannon, and Piacentini are with the Dept of Movement, Human and Health Sciences, University of Rome “Foro Italico,” Rome, Italy. Mignardi is with the School of Sport CONI Lazio, Rome, Italy. Messina is with the Section of Human Physiology, Second University of Naples, Naples, Italy. Villani is with the Unit of Sport Medicine, A.S.L. Foggia, S. Severo, Italy.