Understanding the sleep of ultra-marathon swimmers: Guidance for coaches and swimmers

Abstract

Open water swimming ultra-marathon events ≥10 km have become increasingly popular amongst master athletes. However, very little is known about the timing of training sessions and the impact on sleep. This study aimed to examine sleep behaviours, sleep problems and disorders and the relationship with training timings. This study used a longitudinal observational design for 42 nights with 24 masters' swimmers (n = 13 females), aged 39 ± 11 years, body mass index of 26 ± 3 kg/m2 during a training squad for an ocean ultra-swim (19.7 km) in Western Australia. Objective measures of sleep were obtained from a wrist-activity monitor, the Readiband™ (Fatigue Science Inc., Canada). Swimmers completed a survey instrument related to sleep problems, disorders, chronotype, anthropometric and demographic information. Generalised linear mixed models were fitted to examine relationships between predictor variables and sleep responses. Body mass index was associated with a decline in Total Sleep Time (TST), each one-unit increase in BMI was associated with 5 min less TST (p = 0.04). Swimmers with a “high risk” of sleep apnea had 21 min more wake time (p = 0.04) and 5% lower Sleep Efficiency (p = 0.04). Sleep Offset on the morning of a morning training session was earlier by 48 min (p < 0.001) resulting in less TST by 39 min (p < 0.001). This study provides evidence that coaches need to consider sleep behaviours and problems before designing training schedules. Swimmers need to plan and allocate an adequate sleep opportunity and those who have a suspected sleep disorder or problem should seek the support of a sleep physician.

Athletic retirement: factors contributing to sleep and mental health problems

“…Body mass also predicted risk for sleep difficulty and compromised wellbeing. A study of ultra-marathon swimmers found that higher BMI was associated with reduced total sleep time (Dunican et al, 2022). A systematic review and meta-analysis by Amiri (2023) found a direct linear relationship between BMI and sleep disturbances.…”

Sleep hygiene education for improving sleep in ultra-marathon swimmers: Guidance for coaches and swimmers

“…Interestingly, this study's average sleep onset time of 10:29 pm highlights that participants were primarily moderate morning chronotypes, as previously reported. 4…”

“…A detailed examination of participants’ pre-intervention sleep and the lifestyle- and training-related factors that influence their sleep has already been published. 4 In summary, 8% were obese, 50% were overweight and 63% rated the importance of sleep as extremely important. The potential prevalence of obstructive sleep apnoea (OSA) was 21%, with 67% being moderate morning types (wake up at 07:24) (Supplementary Table 1).…”

“…3 In a previous study, 4 we reported that these swimmers consistently sleep <7 hours per night despite this age group requiring 7–9 hours of total sleep per night, 5 have a high risk of sleep apnoea and have less total sleep time (TST) the night before an early morning training sessions twice a week (<06:00). 4 Poor sleep outcomes in this population may reflect the impact of family, work, study and social commitments, which in addition to athletic training, may leave little opportunity for sleep. Such challenges are also present with youth athletes, with improvements in sleep with a sleep hygiene educational intervention.…”

“…Interestingly, this study's average sleep onset time of 10:29 pm highlights that participants were primarily moderate morning chronotypes, as previously reported. 4 In our study, the intervention was conducted in late November and post-intervention measures were collected in December. A potential factor impacting the inability to increase sleep is the increase in daylight hours.…”