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The Montana Center for Work Physiology and Exercise Metabolism (Montana WPEM) works to design and perform cutting-edge, innovative research that is applicable to occupations and recreational endeavors that push the human body to its limit.

In recent years and under the current AFSOC/AFRL funding, our laboratory has completed the following studies:


Supplemental Feedings for Extended Operations

Photos from field included:

Exogenous carbohydrate spares muscle glycogen in men and women during 10 h of exercise.

Harger-Domitrovich SG, McClaughry AE, Gaskill SE, Ruby BC.

Med Sci Sports Exerc. 2007 Dec;39(12):2171-9.


Carbohydrate feedings reduce rates of glycogenolysis during 8-hours of ultra endurance exercise. Wagner J., S.E. Gaskill, and B.C. Ruby. Manuscript in Preparation, 2007.
These studies demonstrate that supplemental CHO feedings reduced muscle glycogen use during extended work. This strongly suggests that the regular provision of simple carbohydrate sources to the warfighter will reduce the depletion of muscle carbohydrate.


Supplemental feedings increase self-selected work output during wildfire suppression.

Cuddy JS, Gaskill SE, Sharkey BJ, Harger SG, Ruby BC.

Med Sci Sports Exerc. 2007 Jun;39(6):1004-12.

Efficacy of eat-on-move ration for sustaining physical activity, reaction time, and mood.

Montain SJ, Baker-Fulco CJ, Niro PJ, Reinert AR, Cuddy JS, Ruby BC.

Med Sci Sports Exerc. 2008 Nov;40(11):1970-6.

These studies demonstrate that regular supplemental CHO feedings increased work output and maintained cognitive function during wildland fire suppression. It elucidates the importance of regular feeding by warfighters in the field to avoid deleterious effects of under eating.



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Recovery Nutrition, Ergogenic Aids

Photos from field included:

Glycogen resynthesis and exercise performance with the addition of fenugreek extract (4-hydroxyisoleucine) to post-exercise carbohydrate feeding.

Slivka D, Cuddy J, Hailes W, Harger S, Ruby B.

Amino Acids. 2008 Aug;35(2):439-44. Epub 2007 Aug 21.

Following 5 hours of low intensity exercise there was no benefit to adding fenugreek extract, an amino acid supplement, to post-exercise carbohydrate feeding to increase muscle glycogen synthesis. For combatants, this study demonstrated that muscle glycogen stores, which provide fuel to complete physical activity, only recovered 78% during 15 hours of rest and aggressive re-feeding.

Effects of high intensity / low volume and low intensity / high volume isokinetic resistance exercise on postexercise glucose tolerance.


Effects of high intensity / low volume and low intensity / high volume isokinetic resistance exercise on postexercise glucose tolerance.

Miller AD, Ruby BC, Laskin JJ, Gaskill SE.

J Strength Cond Res. 2007 May;21(2):330-5.

This study demonstrated that high intensity strength training promoted a more rapid glucose clearance from the blood compared to low intensity strength training. Post-exercise feeding is typically geared toward endurance athletes, but this study shows that those engaging in strenuous, short-term work need to aggressively re-feed following high intensity exercise.

The addition of fenugreek extract (Trigonella foenum-graecum) to glucose feeding increases muscle glycogen resynthesis after exercise.

Ruby BC, Gaskill SE, Slivka D, Harger SG.

Amino Acids. 2005 Feb;28(1):71-6. Epub 2004 Dec 2.

Following 90-minutes of high intensity, depleting exercise, the provision of a high carbohydrate source in addition to the fenugreek extract enhanced the rate of muscle glycogen recovery. This suggests that traditional approaches to the provision of carbohydrate post-exercise may be enhanced by adding novel amino acids.


Caffeine and carbohydrate supplementation during exercise when in negative energy balance: effects on performance, metabolism, and salivary cortisol.

Slivka D, Hailes W, Cuddy J, Ruby B.

Appl Physiol Nutr Metab. 2008 Dec;33(6):1079-85.

This study has begun to demonstrate that the provision of caffeine alone may have adverse effects during exercise in a nutritionally depleted state. However, when caffeine is added to supplemental carbohydrate, exercise performance can be better maintained while favorably changing the pattern of muscle fuel use. For the warfighter, this suggests that supplemental caffeine should be provided with carbohydrate sources to improve muscle fuel delivery while maintaining the potentially positive stimulatory effects of caffeine. 

Glycogen synthesis after road cycling in the fed state.

Reinert A, Slivka D, Cuddy J, Ruby B.

Int J Sports Med. 2009 Jul;30(7):545-9. Epub 2009 May 19.

These data demonstrate that when supplemental CHO is provided during work, the immediate provision of a post-exercise high carbohydrate source is less influential on speeding muscle glycogen recovery. For the warfighter, these data further suggest that regular feedings during field operations have a positive influence on the immediate exercise bout and also act to jump start muscle recovery so troops are better prepared for multiple days of arduous work.

Effects of a b-glucan supplement on symptoms of upper respiratory infections during 14-days of arduous work. J. Domitrovich, S. Domitrovich-Harger, and B.C. Ruby. Manuscript in preparation. 

This study demonstrated that the daily provision of a b-glucan supplement improved feelings of overall health and reduced the occurrence of upper respiratory infections during 14-days of arduous wildfire suppression. For the warfighter exposed to extended arduous missions, these data suggest that simple anti-oxidants can provide protection against further immuno-suppression and reduce the likelihood of upper respiratory sickness. 

Environmental temperature and glycogen resynthesis.

Naperalsky M, Ruby B, Slivka D.

Int J Sports Med. 2010 Aug;31(8):561-6. Epub 2010 May 12.

Muscle glycogenolysis and resynthesis in response to a half Ironman triathlon: a case study.

Gillum TL, Dumke CL, Ruby BC.

Int J Sports Physiol Perform. 2006 Dec;1(4):408-13.

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Hydration Issues: Water Turnover, Dehydration, Heat/ Cold Stress

Photos from field included:

Effects of an electrolyte additive on hydration and drinking behavior during wildfire suppression.

Cuddy JS, Ham JA, Harger SG, Slivka DR, Ruby BC.

Wilderness Environ Med. 2008 Fall;19(3):172-80.

Supplementing water with electrolytes can reduce the amount of fluid necessary to consume and transport during extended activity (electrolyte supplementation reduced needs by (3.3 L∙d-1). This study provides evidence that warfighters can minimize carrying excessive weight, possibly reducing fatigue during extended exercise.

Hydration status and water turnover of dogsled drivers during an endurance sled dog event in the arctic.

Cox CE, Ruby BC, Banse HE, Gaskill SE.

Int J Circumpolar Health. 2006 Feb;65(1):45-54.

Case study of training, fitness, and nourishment of a dog driver during the Iditarod 1049-mile dogsled race.

Cox C, Gaskill S, Ruby B, Uhlig S.

Int J Sport Nutr Exerc Metab. 2003 Sep;13(3):286-93.

This data demonstrated that even in extreme cold, rates of water turnover are high, further indicating the importance of adequate hydration. For the warfighter, it also demonstrates the importance of practical approaches to the maintenance of fluid intake during cold environments.


Water turnover and changes in body composition during arduous wildfire suppression.

Ruby BC, Schoeller DA, Sharkey BJ, Burks C, Tysk S.

Med Sci Sports Exerc. 2003 Oct;35(10):1760-5.

This was our first water turnover study and demonstrates the highest recorded rates of human water turnover in the literature. These data demonstrate the extreme fluid intake requirements during arduous wildfire suppression (an occupation very similar to extended military operations). For the warfighter, these data reveal the hydration challenges associated with arduous work in hostile environments.

Water turnover, total energy expenditure (TEE), and changes in blood and urinary markers of hydration during the Western States 100 ultra-marathon. Ruby B.C., D. Slivka, J. Cuddy, and W. Hailes. Manuscript in preparation.

 This study is a follow-up field study to the water turnover study with wildland firefighters. However, this investigation sought to determine rates of water turnover, TEE, and hydration markers during 24-30 hours of continuous mountain running. This data will provide pivotal directions towards determining the human ceiling of water turnover and 24 hr TEE and will benefit the warfighter by better identifying the water requirements associated with 24 hour operations. 

Water turnover and hydration during the Ironman World Championship triathlon. Ruby B.C., D. Slivka, W. Hailes, J. Cuddy. Manuscript in preparation.

This study was conducted to better identify the demands for total fluid replacement during 10-12 hours of arduous work. Moreover, the unique environment (hot, humid) associated with this event further exacerbates the extreme need for rapid and high volume fluid replacement (12-16 L.12h-1). For the warfighter, these data provide new data to better establish guidelines for arduous work in hot, humid extreme environments.


Effects of modafinil and sleep loss on physiological parameters.

Cuddy JS, Reinert AR, Hansen KC, Ruby BC.

Mil Med. 2008 Nov;173(11):1092-7.

The purpose of this study was to observe the effects of Modafinil on measures of water turnover (rH2O) and total energy expenditure (TEE) during garrison operations in Air Force Special Tactics Operators. This study revealed that energy expenditures ranged from 4000 to 5700 kcals∙day-1 and, contrary to prior studies, Modafinil does not appear to impact one’s thermoregulatory capabilities.

Alterations in patterns of water turnover during a 21-day period of extreme work. Ruby B.C., D. Slivka, J. Cuddy, W. Hailes. Manuscript in preparation.

This study was designed to determine if the physiological adaptations associated with 21-days of arduous physical activity would alter measures of water turnover. The backdrop for this study was an extreme (5000-6000 exercise load resulting in tremendous stress to the working muscle. For the warfighter, this may provide direction as to how physiological adaptations to training and extended operations may alter hydration requirements.


High work output combined with high ambient temperatures caused heat exhaustion in a wildland firefighter despite high fluid intake

Cuddy JS, and Ruby BC.

Manuscript in Review

The purpose of this case study is to examine the physiological/behavioral factors leading up to heat exhaustion in a male wildland firefighter during wildland fire suppression.The data demonstrate that heat related incidents can occur even with aggressive fluid intake during wildland fire suppression.

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Energy Demands of Extended Work

Total energy expenditure during arduous wildfire suppression.

Ruby BC, Shriver TC, Zderic TW, Sharkey BJ, Burks C, Tysk S.

Med Sci Sports Exerc. 2002 Jun;34(6):1048-54.

Metabolic Profile of the Ironman World Championships: A Case Study.

Ruby, B.C., C. Dumke, D.R. Slivka, W. Hailes, and J.S. Cuddy.

Int J Sports Physiol Perform

Manuscript in press, 2010.

The purpose of this study was to determine the metabolic profile of an athlete during the 2006 Ironman World Championship in Kailua-Kona, HI. These data demonstrate the unique physiological demands of Ironman World Championship and should be considered by athletes and coaches to prepare sufficient nutritional and hydration plans.

The purpose of these studies was to determine energy demands of extended physical work in arduous, volatile environments. For military operators completing hazardous, physically demanding missions, these studies reveal the nutritional needs necessary to maintain appropriate energy balance.

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Cellular Adaptations, Biochemistry of Exercise Adap-tations

Photos from study included:

Effects of 21 days of intensified training on markers of overtraining.

Slivka DR, Hailes WS, Cuddy JS, Ruby BC.

J Strength Cond Res. 2010 Oct;24(10):2604-12.

Changes in mitochondrial gene activation in response to high volume endurance training. D. Slivka, J. Cuddy, W. Hailes, and B.C. Ruby. Article in preparation, 2010.



These projects are novel in that the exercise was completed during an extended 21-day field study. Using ultra-endurance cycling as the exercise mode, we were able to provide a massive exercise load amounting to These projects will determine cellular responses to an extreme exercise load in research participants that are already endurance trained. Applicability to the war fighter includes the potential for dramatic cellular adaptations with high volume training.

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Interaction Between Fabric Design and Environment

Core-temperature sensor ingestion timing and measurement variability.

Domitrovich JW, Cuddy JS, Ruby BC.

J Athl Train. 2010 Nov-Dec;45(6):594-600.

The purpose of this study was to compare measures of core body temperature and sweat rates during outdoor running using different cold weather running jackets. For warfighters, this study demonstrated that lighter weight jackets have the same effect on thermoregulation during exercise as bulkier, hotter garments.

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Physiological Monitoring During Field Situations

Photos from field study included:

The applicability of accelerometers during high altitude mountaineering. Hailes W., J. Cuddy, D. Slivka, and B.C. Ruby, article in preparation, 2010.

The purpose of this study was to monitor physical activity patterns (volume, intensity, and frequency) and estimate energy expenditure during a climbing expedition up Mt. McKinley. This applies to military operations because monitoring capabilities are limited for studying physiological phenomena in remote, high altitude, cold environments.


Measures of activity patterns, estimated TEE and salivary cortisol during Special Tactics Officer Selection School. Cuddy, J. W. Hailes, A. Reinert, D. Slivka, and B.C. Ruby.  Article in preparation, 2010.

The purpose of this study was to analyze physical activity and corresponding physiological stress in response to intense physical and mental strain during 5 days of Air Force Special Tactics Officer (STO) Selection. Salivary cortisol (a biomarker of stress) was elevated compared to baseline following periods of higher activity (marching and pool exercises) but returned to baseline following reduced activity. These data further indicate the potential to use non-intrusive methodologies to capture critical data during arduous military operations.



Use of a wireless multi-channel physiological monitoring system during a half-ironman triathlon: a case study. J. Cuddy, J. Berdanier, B. Marx, M. Spiroski, W. Hailes, T. Gillum, A. Reinert, S. Harber, E. Price, and B.C. Ruby.

The purpose of this study was to determine core, skin, and ambient temperature, drinking characteristics, power output, total energy expenditure, and supplemental carbohydrate intake during half ironman triathlon. For military situations, this study indicated the potential to track complex physiological data under competitive field conditions and demonstrated the versatility of a wireless digital activity monitor to collect data.

Hidalgo Equivital Physiological Monitor Product Review and Data Summary

Cuddy JS, Ruby BC, Santee WR, Karis AJ.

This report consists of two parts, a review of the Hidalgo Equivital Physiological Monitor and other body mounted devices for monitoring physiological status, and a brief overview of the human data collected on 12 wildland firefighters (WLFF) actively engaged in fighting two fires in the western U.S. over a 3-day period.

The data collected from the Hidalgo Equivital™ Physiological Monitor appear reasonable in light of the nature of wildland fire suppression. Core body temperature changes little throughout the day, despite fluctuations in respiratory rate and heart rate. This would be expected, as the body compensates for changes in work rate by sweating more or less to maintain core body temperature. The key components of the Hidalgo unit’s data for this laboratory are the measures of heart rate and respiratory rate, since this laboratory has had difficulty obtaining these measures using other portable monitoring systems.


Core Versus Skin Temperatures in Marathon Runners

Marathon and Beyond, Nov/Dec 2010, Volume 14, Issue 6

John Cuddy and Brent Ruby

The purpose of the project was to determine physiological responses of core and skin temperature during competitive marathon running in middle-aged women. These data demonstrate that in recreational female runners classic measures of peak VO2 and % body fat do not forecast race finish time as accurately as measures of skin temperature and body fat. It is critical to maintain a cool skin temperature during marathon running to maintain favorable heat loss and maximize performance.

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The University of Montana
Montana Center for Work Physiology
and Exercise Metabolism
32 Campus Drive
McGill Hall - HHP
Missoula, MT 59812
(406) 243-2117