Key result
The Trendelenburg position during laparoscopic urological surgery significantly increased the average optic nerve sheath diameter in the right eye from 5.8 mm to 6.6 mm (p<0.000001), which did not correlate with postoperative complications.
Why the study?
The impact of winter swimming on the cardiovascular system remains to be investigated.
Does winter swimming affect heart rate variability and ECG parameters in adult subjects?
Observational (n=69)
No
Does winter swimming affect heart rate variability and ECG parameters in adult subjects?
Absolute Event Rate: 6.6% vs 5.8%
p-value: p=<0.000001
Winter swimming may improve heart rate variability in adults over 45, but high frequency (>1/week) could potentially increase cardiovascular risk by reducing autonomous reserve.
May warrant caution recommending winter swimming; leaves open net cardiovascular effects pending larger prospective data.
OBJECTIVE: Aim: To investigate the impact of winter swimming on the cardiovascular system. PATIENTS AND METHODS: Material and methods: A group of 30 adult subjects underwent an ECG Holter examination twice (during the winter swimming season and after its end). The following parameters available in the results of the ECG Holter examination were analysed: HR, VE and SVE beats, QT and heart rate variability parameters: SDNN, SDANN, pNN50, RMSSD and Tiangular index. RESULTS: Results: In subjects over 45 years of age, higher values of the SDNN and SDANN parameters during the winter period may suggest a positive impact of winter swimming on the cardiovascular system. The QTc max parameter showed higher values in males during the winter study, whereas higher values were recorded in females during the summer study. As the frequency of winter swimming episodes increased, higher HR min values and lower SDNN and SDANN values were observed. CONCLUSION: Conclusions: In healthy subjects under 45 years of age, winter swimming appears to have no significant impact on the heart rate variability parameters, whereas in individuals over 45 years of age, it shows a statistically significant positive impact. Winter swimming practised more frequently than once a week may reduce the autonomous reserve and increase cardiovascular risk. Further research with a larger sample size is necessary to better understand the effects of winter swimming on the cardiovascular system.
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Jurczak et al. (2025) conducted an observational in Urologic surgery requiring Trendelenburg position (n=69). Trendelenburg position vs. Preoperative baseline (horizontal position) was evaluated on Optic nerve sheath diameter (ONSD) in the right eye (p=<0.000001). The Trendelenburg position during laparoscopic urological surgery significantly increased the average optic nerve sheath diameter in the right eye from 5.8 mm to 6.6 mm (p<0.000001), which did not correlate with postoperative complications.
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