Written by Joyce Smith, BS. This study found that decreased use of media devices at bedtime was associated with longer sleep duration and greater sperm quality.
Recent decades have shown a significant decline in sperm concentrations among men in Western and industrialized countries. This is in contrast to non-western countries which have not experienced this trend 1. Contributing factors include obesity 2, environmental toxins 3, mobile phone radiation 4, and stress 5. Although mobile phones are partial contributors to the problem, short wavelength (SWL) light emitted from digital media may also be problematic. Two recent studies suggested that sleep duration may play a role in male spermatogenesis 6,7.
Thus the purpose of this study 8 was to assess the relationship between greater exposure to digital media device screens before bedtime and decline in both sleep and sperm quality. Semen samples from 116 men, 21 to 59 years old, who were undergoing fertility evaluation in a fertility clinic. Samples were evaluated based on volume (mL), pH, sperm concentration (million/mL), motility percentage (progressive% + non-progressive motility%), and total sperm count. Questionnaires provided data regarding participants’ exposure time to electronic device screens as well as their sleep habits.
- Users of smartphone and tablets in the evening and after bedtime and those who watched television in the evening all had a reduction in their quality of sperm. Sperm motility, sperm progressive motility and sperm concentration were all reduced (p < .05 for all) and the percentage of immotile sperm was increased p < .05). In addition, men who slept longer had a higher sperm count and sperm with better motility (p < .05) and better semen quality with a higher pH (p<0.05) compared to men who slept less.
- Sixty % of participants had trouble concentrating in the morning and 30% reported subjective sleepiness both of which were significantly associated with reduced total and progressive motility (−0.264; p < .05) as well as total motile sperm number (p < .05).
- Increased exposure to screen digital devices significantly affected the amount of times that participants woke up during the night and the amount of reports of poor quality sleep.
Was sleep deprivation (due to SWL light) responsible for the decline in sleep quality or did SWL suppress melatonin secretion independently of sleep to produce poor semen quality? SWL from digital screens reduces sleep quality and duration and upsets circadian rhythms when exposure occurs in the evening or before bedtime. Melatonin, a neurohormone, regulates circadian rhythms which when dysfunctional can affect cardiovascular, metabolic and immune system functions. Thus melatonin may also play a role in spermatogenesis.
Since the use of light emitting devices is universal, the use of a control group was not feasible in this study. Other study limitations include a small cohort of participants, no assessment of light sources (bedroom night stand and ceiling lights) beyond media devices, and no confirmation of suppressed melatonin levels. However, study results support the hypothesis that SWL light from media sources is associated with a decline in semen quality; therefore, larger future studies evaluating the effect of melatonin levels on sperm quality are recommended.
Source: Green, Amit, Shlomi Barak, Lior Shine, Arik Kahane, and Yaron Dagan. “Exposure by males to light emitted from media devices at night is linked with decline of sperm quality and correlated with sleep quality measures.” Chronobiology International 37, no. 3 (2020): 414-424.
© 2020 Taylor & Francis Group, LLC
Posted October 13, 2020.
Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.
References:
- Levine H, Jørgensen N, Martino-Andrade A, et al. Temporal trends in sperm count: a systematic review and meta-regression analysis. Hum Reprod Update. 2017;23(6):646-659.
- Macdonald AA, Stewart AW, Farquhar CM. Body mass index in relation to semen quality and reproductive hormones in New Zealand men: a cross-sectional study in fertility clinics. Human reproduction (Oxford, England). 2013;28(12):3178-3187.
- Jurewicz J, Hanke W, Radwan M, Bonde JP. Environmental factors and semen quality. International journal of occupational medicine and environmental health. 2009;22(4):305-329.
- Adams JA, Galloway TS, Mondal D, Esteves SC, Mathews F. Effect of mobile telephones on sperm quality: a systematic review and meta-analysis. Environ Int. 2014;70:106-112.
- Nordkap L, Jensen TK, Hansen Å M, et al. Psychological stress and testicular function: a cross-sectional study of 1,215 Danish men. Fertil Steril. 2016;105(1):174-187.e171-172.
- Jensen TK, Andersson AM, Skakkebæk NE, et al. Association of sleep disturbances with reduced semen quality: a cross-sectional study among 953 healthy young Danish men. Am J Epidemiol. 2013;177(10):1027-1037.
- Chen Q, Yang H, Zhou N, et al. Inverse U-shaped Association between Sleep Duration and Semen Quality: Longitudinal Observational Study (MARHCS) in Chongqing, China. Sleep. 2016;39(1):79-86.
- Green A, Barak S, Shine L, Kahane A, Dagan Y. Exposure by males to light emitted from media devices at night is linked with decline of sperm quality and correlated with sleep quality measures. Chronobiol Int. 2020;37(3):414-424.