Extended Abstract
Background and Purpose
Sleep is restorative in immune, nervous, and endocrine processes (2). Sleep deprivation is a common occurrence during sports competitions (3). Sleep deprivation is usually categorized into total sleep deprivation (TSD) and partial sleep deprivation (PSD) (5). In TSD, a person experiences long-term sleep deprivation. PSD is short-term sleep deprivation.
PSD is more common among athletes (5). PSD may occur due to factors such as sleeping in a new and unfamiliar environment, anxiety before competition, and heavy training (4). PSD can negatively affect the body's physiological function during the athlete's performance. It appears that PSD at the beginning or end of the night may have different effects on anaerobic capacity. This issue has been investigated in a few studies. Research showed that PSD at the end of the night caused a greater decrease in anaerobic power than PSD at the beginning of the night (5, 15, 16). It should be noted that in studies comparing the effect of sleep deprivation at the beginning and end of the night on anaerobic performance, the subjects were male.
Studies show that sleep complaints are almost twice as common in women as in men (17). Women's sleep patterns are different from men's and are influenced by different phases of their menstrual cycle (19). Given that women's participation in sports competitions is growing, it is important to pay attention to and examine the effect of sleep deprivation on women's athletic performance. To date, no study has been conducted on the effect of sleep deprivation on women's anaerobic performance with consideration of menstrual phases. The present study examines the effect of partial sleep deprivation at the beginning and end of the night on anaerobic performance in the luteal and follicular phases of the menstrual cycle in women.
Methods
Fifteen active young women voluntarily participated in this research. Each subject visited the laboratory for two consecutive months in six sessions. Three sessions in the first 14 days of the menstrual cycle (follicular phase) and three sessions in the second 14 days of the menstrual cycle (luteal phase). There were at least 72 hours of rest between test sessions. To investigate the effects of PSD at the beginning and end of the night on anaerobic performance in each phase (follicular or luteal), the subject conducted 3 sleep pattern models the night before the test. The sleep models included 4 hours of PSD at the beginning and end of the night, and full sleep. Three sleep models were applied once in the follicular phase and once in the luteal phase. The Wingate test is used to evaluate anaerobic power (Ergomedic 894E, Monark, Sweden) (14). The SPSS software (v.25) and the repeated measures analysis of variance were used for statistical analysis.
Results
The results showed that peak and mean anaerobic power in the luteal phase were significantly lower than the follicular phase (p = 0.001), respectively 38.9 ± 14.59 and 33.5 ± 1.42. Also, regardless of menstrual phase, PSD at the end of the night compared to full sleep resulted in a decrease in peak anaerobic power by 57.8 ± 24.87 (p = 0.001).
Conclusion
In the present study, anaerobic performance decreased after PSD at the end of the night. Since no similar study has been conducted to date that has examined the effects of PSD at the beginning and end of the night on the phases of the menstrual cycle in women, we cannot directly compare the results of the present study with previous studies. Research shows that PSD at the end of the night reduces anaerobic performance in men (15). In the present study, a decrease in anaerobic performance in women was also observed after PSD at the end of the night compared to full sleep. Several factors contribute to the decline in anaerobic performance in active women due to sleep deprivation at the end of the night. Disruption in melatonin secretion after PSD can impact sleep quality and thus explain the decline in athletic performance (9). In the present study, PSD at the end of the night might have caused greater disruption to melatonin secretion. Other factors affecting the reduction of anaerobic performance with PSD at the end of the night include impaired regeneration of energy stores such as phosphocreatine and muscle glycogen (30).
Another result of the present study was a decrease in peak anaerobic power in active women in the luteal phase compared to the follicular phase. There is less consistent evidence that anaerobic power declines in the luteal phase, but many studies show that the difference between the luteal and follicular phases is small and variable. These responses depend on training level, the presence of premenstrual syndrome, the method used to determine the menstrual phase, and the type of anaerobic test (34, 35, 36).
The findings showed that PSD at the beginning of the night did not affect women's anaerobic power. However, PSD at the end of the night decreased women's anaerobic performance regardless of menstrual cycle phase. Women's anaerobic performance was also reduced in the luteal phase compared to the follicular phase.
Article Message
Partial sleep deprivation at the beginning of the night and the follicular phase does not affect anaerobic performance in active women. However, partial sleep deprivation at the end of the night leads to a decline in anaerobic power in active women. Women's anaerobic performance is also impaired in the luteal phase of the menstrual cycle. This may be particularly important for women participating in high-level competition.
Ethical Considerations
The present study was approved by the Ethics Committee of the Sport Sciences Research Institute, Ministry of Science, Research, and Technology, under the ethics code IR.SSRC.REC.1403.021. All research procedures were conducted in accordance with the relevant ethical guidelines and protocols.
Authors' Contributions
Conceptualization: Sahar Mirzaei Ezbarami, Leila Ghazaleh
Data Collection: Sahar Mirzaei Ezbarami
Data Analysis: Leila Ghazaleh, Sahar Mirzaei Ezbarami
Manuscript Writing: Sahar Mirzaei Ezbarami, Leila Ghazaleh, Fereshteh Shahidi
Review and Editing: Leila Ghazaleh, Fereshteh Shahidi
Responsible for funding: None.
Literature Review: Sahar Mirzaei Ezbarami
Project Manager: Leila Ghazaleh
Any other Contributions: All authors have read and approved the final manuscript.
Conflict of Interest
The authors declared no conflict of interest.
Acknowledgments
The authors gratefully acknowledge all participants who volunteered as subjects in this study