Glycogen levels in wildland firefighters during wildfire suppression

John S. Cuddy, Dustin R. Slivka, Tyler J. Tucker, Walter S. Hailes, Brent C. Ruby

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Objective The purpose of this project was to determine the effects of wildfire suppression on muscle glycogen utilization in wildland firefighters (WLFFs). Methods Wildland firefighters (n = 11) participated in the study. Muscle biopsies were obtained from the vastus lateralis pre- and post-work shift. Activity patterns were measured using an Actical activity monitor positioned on the chest. Food was consumed ad libitum and recorded using a food log and interview. Differences were analyzed using paired samples t-tests and relationships were assessed using Pearson r correlation coefficients. A significance level of p < .05 was set. Results Body weight was similar pre- to post-work shift (85.9 ± 9.1 and 85.6 ± 8.8 kg, respectively). Muscle glycogen decreased from pre- to post-work shift, 101 ± 7 to 80 ± 5 mmol/kg wet wt, p < .05. Average activity counts were 175 ± 60 counts/min. Mean percent of time spent in each intensity category included: sedentary (74 ± 7%), light (21 ± 5%), and moderate/vigorous (5 ± 2%). There was a significant relationship between minutes completing vigorous activity and glycogen utilization (r = -.76, p < .05), and between minutes spent completing vigorous activity and pre-shift glycogen content (r = .79, p < .05). Kilocalorie intake during the work shift was 9.2 ± 2.9 MJ/d (2195 ± 699 kcal/d). Conclusions This study demonstrates the variety of self-selected nutritional and activity habits of WLFFs, and emphasizes the relationships between moderate/vigorous activity and muscle glycogen. The current data suggest that the food provided was adequate to maintain muscle glycogen levels pre- to post-work shift.

Original languageEnglish
Pages (from-to)23-27
Number of pages5
JournalWilderness and Environmental Medicine
Issue number1
StatePublished - Mar 2011


  • muscle glycogen
  • wildfire suppression
  • wildland firefighters


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