Energy Balance during Backpacking

Abstract

Energy expenditure and energy intake were determined in three subjects during a 160-kilometer backpacking trip. Prior to the trip, heart rate and oxygen consumption during treadmill walking while carrying a backpack were measured. Subjects recorded heart rate during hiking. Heart rate was used to estimate energy expenditure based on the heart rate : oxygen consumption relationship (Heart Rate Method). Expenditure was also estimated from distance walked and elevation gained (Terrain Method). Subjects recorded food consumption, and were weighed upon finishing the hike. Mean heart rate during hiking was 105 ± 12 beats per minute. According to the Heart Rate Method, net expenditure averaged 3410 ± 955 kilocalories on days 1 – 4, and 2586 ± 974 kilocalories on day 5. Net expenditure from the Terrain Method was approximately 28 % lower. Gross expenditure, using the Heart Rate Method, averaged 4928 ± 1050 kilocalories on days 1 – 4, and 3550 ± 1052 kilocalories on day 5. Energy intake averaged 2134 ± 625 kilocalories on days 1 – 4, and 1117 ± 320 kilocalories on day 5. Expected weight loss due to the caloric deficit was 1.8 ± 0.4 kilograms, and actual weight loss was 1.7 ± 0.6 kilograms. Subjects expended nearly 5000 kilocalories per day and did not consume sufficient food to maintain body mass.

oxygen consumption - energy expenditure - energy intake - heart rate

References

• 1 Albert C M, Mittleman M A, Chae C U, Lee I M, Hennekens C H, Manson J E. Triggering of sudden death from cardiac causes by vigorous exertion.  N Engl J Med. 2000;  343 1355-1361
• 2 American College of Sports Medicine .ACSM's Guidelines for Exercise Testing and Prescription. 7th edn. Vol. 4. Philadelphia; Lippincott Williams and Wilkins 2006: 286-289
• 3 DeVoe D E. Heart rate responses during a multi-day backpacking excursion.  J Hum Mov Studies. 2000;  38 213-224
• 4 DeVoe D. Caloric expenditure during backpacking.  J Hum Mov Studies. 2001;  40 259-268
• 5 DeVoe D, Dalleck L. Reliability and validity of the Tritrac-R3D accelerometer during backpacking: a case study.  Percept Mot Skills. 2001;  93 37-46
• 6 Jacobson B H, Wright T, Dugan B. Load carriage energy expenditure with and without hiking poles during inclined walking.  Int J Sports Med. 2000;  21 356-359
• 7 Knight C A, Caldwell G E. Muscular and metabolic costs of uphill backpacking: are hiking poles beneficial?.  Med Sci Sports Exerc. 2000;  32 2093-2101
• 8 Laursen B, Ekner D, Simonsen E B, Voigt M, Sjogaard G. Kinetics and energetics during uphill and downhill carrying of different weights.  Appl Ergonomics. 2000;  31 159-166
• 9 Legg S J, Ramsey T, Knowles D J. The metabolic cost of backpack and shoulder load carriage.  Ergonomics. 1992;  35 1063-1068
• 10 Lloyd R, Cooke C B. The oxygen consumption associated with unloaded walking and load carriage using two different backpack designs.  Eur J Appl Physiol. 2000;  81 486-492
• 11 Minetti A E, Moia C, Roi G S, Susta D, Ferretti G. Energy cost of walking and running at extreme uphill and downhill slopes.  J Appl Physiol. 2002;  93 1039-1046
• 12 Mittleman M A, Maclure M, Tofler G H, Sherwood J B, Goldberg R J, Muller J E. Triggering of acute myocardial infarction by heavy physical exertion: protection against triggering by regular exertion.  N Engl J Med. 1993;  329 1677-1683
• 13 Saris W HM, van Erp-Baart M A, Brouns F, Westerterp K R, ten Hoor F. Study on food intake and energy expenditure during extreme sustained exercise: the Tour de France.  Int J Sports Med. 1989;  10 S26-S31