English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Background: U.S. Army Rangers must maintain a high level of physical fitness in order to be successful during training and deployment missions. The hormone testosterone increases muscle growth and strength, which leads to better physical fitness and performance. Therefore, maintaining high testosterone levels is of critical importance to this unit. However, many Ranger missions require sleep deprivation, which, in non-military populations, has been shown to decrease testosterone. The purpose of the study was to test the impact of sleep deprivation during military training on U.S. Army Ranger testosterone levels. Methods: In two studies surrounding Ranger training missions, salivary testosterone was measured within subjects during a rested condition and following sleep loss in male participants (Study 1 n = 76 males; Study 2 n = 44 males). Testosterone levels were compared using paired-sample t-tests. Additionally, given the diurnal secretion of testosterone, we compared testosterone levels assessed after sleep deprivation to historical data measured at the same time of day in participants who were well-rested. Results: In Study 1, testosterone significantly decreased from 105.91 ± 35.35 to 79.87 ± 35.65 pg/mL (a 28% reduction) after sleep deprivation (t (75) = 5.85, p = 0.001). Similarly, in Study 2, following sleep deprivation, testosterone significantly decreased from 115.31 ± 28.44 to 89.29 ± 29.00 pg/mL (a 25.4% reduction; t (43) = 4.81, p = 0.001). In addition, Ranger testosterone was roughly 90% lower than historical data sampled at the same time of day. Conclusion: These data add to the growing body of literature showing that loss of sleep decreases testosterone, which may ultimately have a negative impact on physical training and performance in physically elite populations like the U.S. Army Rangers.

Sleep Loss during Military Training Reduces Testosterone in U.S. Army Rangers: A Two-Study Series