Sex-specific differences in circadian sleep profiles were found among liver transplant candidates, with men exhibiting longer sleep duration, greater movement, and higher pre-sleep light exposure, whereas women demonstrated superior sleep efficiency and a delayed core sleep phase.
Key Findings
Results
Significant sex-based differences in actual sleep time were found among liver transplant candidates on the waiting list.
50 patients total: 40 men and 10 women on the waiting list at Hospital Clínico Universitario Virgen de la Arrixaca (Murcia, Spain)
Men exhibited longer sleep duration than women
Difference in actual sleep time was statistically significant (p = .03)
Patients wore the Kronowise K6 wrist device on their nondominant wrist for 1 week pre-transplantation
42 variables related to sleep quality and circadian rhythms were assessed via Student's t-test
Results
Women demonstrated superior sleep efficiency compared to men despite shorter sleep duration.
Sleep efficiency difference was statistically significant (p = .022)
Women achieved better sleep quality even with shorter overall sleep duration
The authors suggest this may be related to behavioral differences in pre-sleep routines
Results
Men exhibited significantly greater total movement time during sleep compared to women.
Total movement time difference was statistically significant (p = .011)
Greater movement in men was identified as one of the less favorable sleep hygiene indicators in male patients
This was one of four variables showing significant sex-based differences out of 42 assessed
Results
Men had significantly higher blue light exposure before sleep compared to women, up to 2.5 times greater.
Blue light exposure before sleep difference was statistically significant (p = .04)
Women's pre-sleep blue light exposure was up to 2.5 times less than that of men
The authors attribute this disparity likely to differing pre-sleep behaviors, such as screen use
Reduced blue light exposure in women was proposed as a potential explanation for their superior sleep efficiency
Results
Women's core sleep phase was delayed by approximately 30 minutes compared to men.
The midpoint of sleep-related peak values occurred later in women
Women's core sleep phase was delayed by approximately 30 minutes
This delay suggests sex-specific differences in circadian timing among this patient population
Conclusions
Sex-specific differences in circadian sleep profiles among liver transplant candidates suggest targeted pre-transplant sleep interventions may be warranted for men.
Men's less favorable sleep hygiene indicators included longer sleep duration with lower efficiency, greater movement, and higher blue light exposure
The authors suggest targeted interventions to improve pre-transplant sleep health specifically for men
Sleep was characterized as 'a critical component of health' that is 'underexplored in patients awaiting organ transplantation'
Data were analyzed using Kronowise 100 software (Kronohealth, Spain)
What This Means
This research suggests that male and female patients waiting for a liver transplant have meaningfully different sleep patterns in the week before their transplant. In a study of 50 patients in Spain who wore wrist-based sleep monitors for one week, men slept longer overall but had lower sleep efficiency (meaning more of their time in bed was not productive sleep), moved around more during the night, and were exposed to significantly more blue light — the kind emitted by screens — before going to sleep. Women, despite sleeping for shorter periods, achieved better quality sleep and tended to fall into their core sleep phase about 30 minutes later in the night than men.
One of the most striking findings was that men were exposed to up to 2.5 times more blue light before sleep than women, which the researchers suggest is likely due to greater screen use (such as phones or televisions) in the hours before bed. Blue light exposure is known to interfere with the body's natural sleep signals, which may help explain why men's sleep was less efficient. Women's later sleep timing also points to differences in circadian (internal body clock) rhythms between sexes in this patient group.
This research matters because patients on organ transplant waiting lists are already under significant physical and psychological stress, and poor sleep can affect surgical outcomes and overall health. The findings suggest that sleep health programs designed for liver transplant candidates may need to be tailored differently for men and women, with particular attention to reducing screen use and blue light exposure before bed among male patients.
Martínez-Alarcón L, Jover-Aguilar M, Sáez-Sánchez J, Romero P, Vidal G. (2026). Differences in Circadian Sleep Parameters as a Function of Gender in Patients on the Waiting List for Liver Transplantation.. Transplantation proceedings. https://doi.org/10.1016/j.transproceed.2026.01.021