Effects of Hot Night Exposure on Human Semen Quality: A Multicenter Population-Based Study.

Ting Ting DAI; Ting XU; Qi Ling WANG; Hao Bo NI; Chun Ying SONG; Yu Shan LI; Fu Ping LI; Tian Qing MENG; Hui Qiang SHENG; Ling Xi WANG; Xiao Yan CAI; Li Na XIAO; Xiao Lin YU; Qing Hui ZENG; Pi GUO; Xin Zong ZHANG

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Effects of Hot Night Exposure on Human Semen Quality: A Multicenter Population-Based Study.

Author: Ting Ting DAI ¹ ; Ting XU ¹ ; Qi Ling WANG ² ; Hao Bo NI ¹ ; Chun Ying SONG ³ ; Yu Shan LI ⁴ ; Fu Ping LI ⁵ ; Tian Qing MENG ⁶ ; Hui Qiang SHENG ⁷ ; Ling Xi WANG ¹ ; Xiao Yan CAI ¹ ; Li Na XIAO ¹ ; Xiao Lin YU ¹ ; Qing Hui ZENG ¹ ; Pi GUO ¹ ; Xin Zong ZHANG ²
Author Information

1. Department of Preventive Medicine, Shantou University Medical College, Shantou 515041, Guangdong, China.
2. National Health Commission Key Laboratory of Male Reproduction and Genetics, Guangzhou 510600, Guangdong, China;Department of Andrology, Guangdong Provincial Reproductive Science Institute (Guangdong Provincial Fertility Hospital), Guangzhou 510600, Guangdong, China.
3. Human Sperm Bank, the Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Taiyuan 030032, Shanxi, China.
4. Human Sperm Bank, the Third Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, Henan, China.
5. Human Sperm Bank, the Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education, West China Second University Hospital of Sichuan University, Chengdu 610041, Sichuan, China.
6. Reproductive Medicine Center, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China;Human Sperm Bank, Reproductive Medicine Center, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China.
7. Human Sperm Bank, the Zhejiang Provincial Maternal and Child and Reproductive Health Care Center, Hangzhou 310012, Zhejiang, China.
Publication Type:Multicenter Study
Keywords: Climate change; Exposure-response relationship; Hot night exposure; Human semen quality; Multicenter study
MeSH: Humans; Male; Semen Analysis; Adult; Sperm Motility; Hot Temperature/adverse effects*; China; Middle Aged; Spermatozoa/physiology*; Young Adult
From: Biomedical and Environmental Sciences 2025;38(2):178-193
CountryChina
Language:English
Abstract: OBJECTIVE:To explore and quantify the association of hot night exposure during the sperm development period (0-90 lag days) with semen quality.
METHODS:A total of 6,640 male sperm donors from 6 human sperm banks in China during 2014-2020 were recruited in this multicenter study. Two indices (i.e., hot night excess [HNE] and hot night duration [HND]) were used to estimate the heat intensity and duration during nighttime. Linear mixed models were used to examine the association between hot nights and semen quality parameters.
RESULTS:The exposure-response relationship revealed that HNE and HND during 0-90 days before semen collection had a significantly inverse association with sperm motility. Specifically, a 1 °C increase in HNE was associated with decreased sperm progressive motility of 0.0090 (95% confidence interval [ CI]: -0.0147, -0.0033) and decreased total motility of 0.0094 (95% CI: -0.0160, -0.0029). HND was significantly associated with reduced sperm progressive motility and total motility of 0.0021 (95% CI: -0.0040, -0.0003) and 0.0023 (95% CI: -0.0043, -0.0002), respectively. Consistent results were observed at different temperature thresholds on hot nights.
CONCLUSION:Our findings highlight the need to mitigate nocturnal heat exposure during spermatogenesis to maintain optimal semen quality.