Heart rate changes after ultra-endurance swim from italy to albania: a case report

PURPOSE: To evaluate the effect of a solo ultra-endurance open-water swim upon autonomic and non-autonomic control of heart rate (HR). METHODS: A male athlete (age: 48yr, height, 172 cm; body mass, 68 kg; BMI, 23 kg/m2) underwent the heart rate variability (HRV) and circulating catecholamine evaluations at different time intervals before and after an ultra-endurance swim, crossing the Adriatic sea from Italy to Albania. The HRV was measured in 5-minutes segments and quantified by time-and frequency-domain. Circulating catecholamines were extimated by salivary alpha-amylase (sAA) assay. RESULTS: The athlete completed 78.1 km in 23:44 hr:min. After arrival, sAA levels 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%; LF low frequency, -78.0%; high frequency, -76.4%); while HR increased by 41.8%. At 16-hr recovery, sAA returned to pre-event values; while, a stable tachycardia was accompanied by reduced HRV measures. CONCLUSION: To our knowledge, this is the first study reporting cardiac autonomic adjustments to an extreme and challanging ultra-endurance open-water swim. Our findings confirmed that the autonomic drives depend upon exercise efforts. Since HRV changes did not mirror the catecholamine response 16-hr post-event, we assume that ultra-endurance swim differently influenced cardiac function by both adaptive autonomic and non-autonomic patterns.