Effects of Caffeine on Basal Metabolic Rate and Metabolism of Fat and Carbohydrate During Moderate Exercise

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Effects of Caffeine on Basal Metabolic Rate and
Metabolism of Fat and Carbohydrate During
Moderate Exercise

• By Adam Michalik

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Introduction

• The purpose of this study was
• 1) To analyze the effects of caffeine on basal
  metabolic rate (BMR).
• 2) To analyze the effect caffeine has on the
  percentage of calories burned as fat versus
  calories burned as carbohydrate during moderate
  exercise.

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Hypotheses

• There will be a significant increase in resting
  energy expenditure when caffeine is consumed
  prior to measurement of basal metabolic rate.
• The percentage of calories burned as fat will
  increase while percentage of calories burned as
  carbohydrate will decrease during moderate
  exercise.
• Decreasing RQ value towards 0.70

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Methods

• Two separate trials consisting of a basal
  metabolic rate test along with two five minute
  exercise periods, one at 2.5 mph and the other at
  4.0 mph.
• BMR Test Protocol
• Trial one - only water
• Trial two - consume approx. 300 mg of caffeine
  1-1.5 hours before arriving to the HHP lab.
• Expired air was analyzed for both tests to
  determine BMR, BMR RQ, exercise HR, exercise
  oxygen consumption, and exercise RQ for both
  caffeinated and non-caffeinated states.

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Methods

• Equipment used
• VO2 metabolic measurement system
• Motor driven treadmill
• Statistical Analysis
• Multiple Paired T-tests

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Descriptive Statistics
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Results BMR and RQ
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Results Heart Rate
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Results Oxygen Consumption
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Discussion

• The comparison between caffeinated and
  non-caffeinated exercise HR _at_ 2.5 mph resulted in
  a significant difference (Plt0.05).
• Bell claimed that HR increased over time, and
  values were further increased after caffeine
  ingestion. 2
• Caffeine tended to produce higher values for BMR,
  exercise HR, and exercise oxygen consumption at
  2.5 mph.
• Acheson reports that caffeine/coffee stimulates
  the metabolic rate in both control and obese
  individuals. 1
• Caffeine produced a small but significant
  increase in VO2 after 15 minutes of exercise for
  both users and nonusers of caffeine.2

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Discussion

• Exercise oxygen consumption at 4.0 showed slight
  decrease with caffeine (0.25 mL/kg.min)
• 1.4 decrease
• Exercise and resting RQ increased while
  caffeinated
• Data suggests increased CHO utilization
• Research
• Acheson increased plasma FFAs result in
  increased fat oxidation. This is masked through
  alteration of RQ by hyperventilation.
• Cox inability to measure substrate utilization

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Summary

• Caffeine significantly increased exercise HR _at_
  2.5 mph
• Caffeine produced higher values for BMR, exercise
  HR, and exercise oxygen consumption at 2.5 mph
• Not significant
• Caffeine decreased exercise O2 consumption _at_ 4.0
  mph
• Not significant
• Exercise and resting RQ increased with caffeine
  use
• Not significant
• For the future
• Standardization of testing, caffeine consumption,
  more subjects

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Acknowledgements

• A special thanks to
• Dr. Carey
• Subjects

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References

• 1) Acheson, K. J., Zahorska-Markiewicz, B.,
  Pittet, Ph., Anantharam, K., Jequier, E. (1980).
  Caffeine and coffee their influence on metabolic
  rate and substrate utilization in normal weight
  and obese individuals. The American Journal of
  Clinical Nutrition, 33, 989-997.
• 2) Bell, Douglas G., McLellan, Tom M. (2002).
  Exercise endurance 1, 3, and 6 h after caffeine
  ingestion in caffeine users and nonusers. Journal
  of Applied Physiology, 93, 1227-1234.
• 3) Cox, G. R., Desbrow, B., Montgomery, P. G.,
  Anderson, M. E., Bruce, C. R., Macrides T. A.,
  Martin D. T., Moquin, A., Roberts, A., Hawley, J.
  A., Burke, L. M. (2002). Effect of different
  protocols of caffeine intake on metabolism and
  endurance performance. Journal of Applied
  Physiology, 93, 990-999.
• 4) Haldi, J., Bachmann, G., Ensor, C., Wynn, W.
  (1940). The Effect of Various Amounts of
  Caffeine on the Gaseous Exchange and the
  Respiratory Quotient in Man. The Journal of
  Nutrition, 307-320.
• 5) Hallal, Janice C. (1986). Caffeine Is It
  Hazardous to Your Patients Health? The American
  Journal of Nursing, 84(4), 422-425