title: Integrative physiological and behavioural responses to sudden cold-water immersion are similar in skilled and less-skilled swimmers.
abstract: We examined the initial physiological responses and subsequent capacity to swim following cold-water immersion. An ecologically-valid model was used whereby immersion was sudden (<2s) and participants had to actively remain afloat. Participants (15 skilled swimmers, 17 less-skilled swimmers) undertook four experimental test sessions: a physiological test and a swimming test in both cold (10°C) water and temperate (27°C) water in a swimming flume (temperature order counter-balanced). For physiological testing, measures of brain perfusion [flow velocity (MCAv, Doppler) and oxygenation (NIRS)] and cardiorespiratory function [ventilation parameters and end-tidal PCO2 (PETCO2)] were recorded whilst treading water for 150s. The swimming test involved treading water (150s) before swimming at 60% (up to 120s) and 90% (to intolerance) of pre-determined maximum velocity. Multifactorial analysis revealed that swimming duration was influenced most heavily by water temperature, followed by respiratory variables and MCAv in the first 30s of immersion. The time course and severity of cold shock were similar in both groups (p=0.99), in terms of initial physiological changes (MCAv down ~20 ± 11%, respiratory frequency increased to 58 ± 18 breaths·min(-1), PETCO2 dropped to 12 ± 9 mmHg). Treading water following cold-water immersion increased MCAv by 30% above resting values despite maintained cold-shock-induced hyperventilation. In comparison to temperate water, swimming capacity was also reduced similarly between groups in the cold (i.e., distance decreased by 34 ± 26% skilled; 41 ± 33% less-skilled, p=0.99). These integrative findings verify that sudden cold-water immersion followed by physical activity leads to similar physiological responses in humans when contrasting between skilled and less-skilled swimmers.
authors.affiliation: School of Physical Education, Sport and Exercise Sciences, University of Otago, New Zealand. Electronic address: chris.button@otago.ac.nz.
authors.forename: Chris
authors.initials: C
authors.lastname: Button
authors.affiliation: Centre for Exercise and Sports Science Research, Edith Cowan University, Perth, Australia.
authors.forename: James L
authors.initials: JL
authors.lastname: Croft
authors.affiliation: School of Physical Education, Sport and Exercise Sciences, University of Otago, New Zealand.
authors.forename: James D
authors.initials: JD
authors.lastname: Cotter
authors.affiliation: School of Physical Education, Sport and Exercise Sciences, University of Otago, New Zealand.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Graham
authors.affiliation: School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, United Kingdom.
authors.forename: Samuel J E
authors.initials: SJ
authors.lastname: Lucas
mesh_terms: D000293:Adolescent; D000328:Adult; D056352:Athletes; D001921:Brain / Q000098:blood supply / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology; D003080:Cold Temperature / Q000009:adverse effects*; D006801:Humans; D016857:Hypocapnia / Q000209:etiology / Q000503:physiopathology; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D012119:Respiration; D012720:Severity of Illness Index; D012769:Shock / Q000209:etiology / Q000503:physiopathology*; D013550:Swimming / Q000502:physiology*; D014867:Water; D055815:Young Adult
chemical_list: D014867:Water
keywords: Cold shock; Drowning; Hyperventilation; Survival; Treading water