Evidence of Impact of Outdoor Swimming on Health using an Online Survey (Preprint)

BACKGROUND Outdoor swimming has grown in popularity in many countries including the UK. Many anecdotal accounts indicate an improvement in medical conditions which are considered a consequence of outdoor swimming. OBJECTIVE This study aimed to better understand outdoor swimmers’ perceptions of their health and the extent to which participation impacted upon their existing, self-reported symptoms. METHODS A survey was deployed investigating outdoor swimming behaviours and reports of any diagnosed medical conditions, if any. Medical conditions were coded into categories and descriptive statistics generated regarding the outdoor swimmers’ behaviours and about the effect outdoor swimming had on their medical symptoms, if any. The medical categories were clustered in to five larger categories based on their prevalence in the current sample: mental health, musculoskeletal & injury, neurological, cardiovascular & blood disease, ‘Other’ which consists of all conditions not categorised in the four previous groups. RESULTS In total, 722 outdoor swimmers responded, of which 498 (69%) were female. The probability of outdoor swimming having ‘some impact’ on health across all medical categories was 3.57 times higher compared to no impact (B=1.28,95% CI [0.63, 1.91], P<.001), 44.32 times higher for the mental health category (B=3.79, 95% CI [2.28, 5.30], P<.001), 5.25 times higher for Musculoskeletal & injury category (B = 1.66, 95% CI [0.52, 2.79], P=.004) and 4.02 times higher for ‘Other’ category (B = 1.39, 95% CI [0.27, 2.51], P=.015). Overall, outdoor swimming was associated with perceived reductions in symptoms of poor mental health (2(2)=25.099, P<0.001), musculoskeletal and injury (2 (2)=8.242, P=.038), cardiovascular and blood (2(2)=14.685, P=.006) and ‘other’ conditions (2(2)= 18.213, P<.001). CONCLUSIONS Physical activity taken in the form of outdoor swimming is perceived to have positive impacts on health and is associated with perceived symptom reductions in mental health, musculoskeletal, cardiovascular and respiratory conditions. This study cannot provide causal relationships, or provide mechanistic insight. It does, however, provide a starting point for more targeted prospective intervention research into individual conditions or categories of condition to establish the impact in those who choose to start outdoor swimming.