The Impact of Early Morning Training Sessions on Total Sleep Time in Collegiate Athletes

International Journal of Exercise Science 15(6): 423-433, 2022. Early morning training sessions may affect sleep quantity in athletes. The purpose of this study is to examine differences in total sleep time of collegiate athletes on nights prior to early morning training sessions relative to non-training nights. Wristwatch monitors equipped with photoplethysmography and accelerometer technology were worn by 18 NCAA Division III collegiate athletes (Age: 20.1 ± 1.6 years, Height: 1.81 ± 0.02 m, Body Mass: 91.2 ± 6.5 kg, Body Fat %: 20.8 ± 1.6%) during a two-week period of training to monitor total sleep times. Athletes recorded time in and out of bed using a sleep diary, anxiety levels due to having to wake up in the morning, and perceived recovery status (PRS) upon waking the next day. The data were divided into: nights before non-training days (NT) and Training days (TD). Data were analyzed using univariate analysis. All athletes obtained significantly less total sleep on nights before TD relative to NT (NT: 8:15 ± 1:03 vs. TD: 6:08 ± 0:59 hh:mm; p \u3c 0.05). There was a positive relationship between total sleep time and recovery status (p \u3c 0.01). Anxiety scores were inversely related to total sleep time (p \u3c 0.01). Next-day recovery status was inversely related to anxiety scores (p \u3c 0.001). College athletes obtained significantly less total sleep time on nights before early morning training sessions (\u3c 0700) during the off-season, regardless of sex and sport. Coaches should consider later training sessions or promote optimal sleep quantity in order to minimize the risks associated to early morning training sessions

13-lined ground squirrel platelets exhibit rod conformation that reduces rates of liver cell phagocytosis

Thrombocytopenia, or low levels of platelets in blood, is a symptom of various conditions and is typically treated via platelet transfusions. Donated platelets must be stored at room temperature due to structural damages when chilled, which leads to rapid clearance via liver cells and macrophages post-transfusion. Storage at room temperature leads to a 5-day shelf life, susceptibility to microbial contamination, and limits supply. Hibernating mammals like 13-lined ground squirrels (Ictidomys tridecemlineatus) have platelets that are resistant to cold storage lesions and may reduce phagocytosis. Human and ground squirrel platelets were stored in cold and room temperature, exposed to receptor-glycan-specific enzymes, fluorescently labeled, incubated with HepG2 cells, and HepG2 fluorescence was measured via flow cytometry. Long-term-cold-stored ground squirrel platelets were taken up by HepG2 cells at a significantly slower rate than both control ground squirrel platelets and taxol-treated human platelets (P. 0.10) while sialic acid was lost in human platelets after cold storage (P < 0.01). Further sequestration and platelet receptor clustering experiments should be performed to better understand how ground squirrel platelets withstand repeated temperature cycles without rapid clearance post-transfusion