Caffeine and energy drink use by combat arms soldiers in Afghanistan as a countermeasure for sleep loss and high operational demands

Abstract

Objectives

Combat deployments are characterized by high operational demands with limited opportunities for sleep leading to fatigue and degraded cognitive and operational performance. Caffeine in moderate doses is recognized as an effective intervention for physical and cognitive decrements associated with sleep loss.

Methods

This report is based on data collected by two separate, independently conducted surveys administered in Afghanistan in 2011–2012. It assessed caffeine use and sleep disruption among U.S. Army combat soldiers (J-MHAT 8; n = 518) and among deployed soldiers with different military assignments (USARIEM Deployment Survey; n = 260).

Results

Daily caffeine intake assessed in the J-MHAT 8 survey averaged 404 ± 18 mg. In the USARIEM Deployment Survey, intake was 303 ± 29 mg and was significantly higher among combat arms soldiers (483 ± 100 mg) compared to combat service support personnel (235 ± 23 mg). In both surveys, over 55% of total caffeine intake was from energy drinks. Additional sources of caffeine included coffee, tea, sodas, gum, candy, and over-the-counter medications. Higher caffeine intake was not associated with ability to fall asleep at night or wake-up in the morning (J-MHAT 8 survey). Higher caffeine consumption was associated with disrupted sleep from high operational tempo and nighttime duties of combat operations.

Discussion

Overall caffeine consumption and energy drink use in Afghanistan was greater than among non-deployed soldiers and civilians. Caffeine was frequently used as a countermeasure during night operations to offset adverse effects of sleep loss on physical and cognitive function, consistent with current Department of the Army recommendations.

Keywords:

• Coffee
• Cola beverages
• Caffeinated gum
• Military
• Stress

Acknowledgements

The investigators have adhered to the policies for the protection of human subjects as prescribed in DOD Instruction 3216.02 and the research was conducted in adherence to the provisions of 32 CFR Part 219. The opinions or assertions contained herein are the private views of the author(s) and are not to be construed as official or as reflecting the views of the Army or the Department of Defense. Citations of commercial organizations and trade names in this report do not constitute an official Department of the Army endorsement or approval of the products or services of these organizations.

K.W. Williams was supported by the Oak Ridge Institute for Science and Education through an interagency agreement between the U.S. Department of Energy and US Army Medical Research and Materiel Command. T.M. McLellan was supported by the Oak Ridge Institute for Science and Education, as well as through a consulting agreement with the Henry M. Jackson Foundation for the Advancement of Military Medicine Inc.

Disclaimer statements

Contributors None.

Funding This work was supported by the Center Alliance for Nutrition and Dietary Supplement Research of the Defense Medical Research and Development Program and the Military Operational Medical Research Program of the U.S. Army Medical Research and Materiel Command.

Conflict of interest There are no conflicts of interest to disclose by any author of this work.

Ethics approval The surveys were approved by Human Use/Institutional Review Boards.