DSES101 Introduction to Sport & Exercise Physiology: Lab Report

This report investigates the utilization of fat and carbohydrates during incremental exercise, focusing on how these substrates are affected by increasing work power. Four healthy male participants underwent cycling on an ergometer with gradually increasing power outputs (60W, 90W, and 120W). Expired gases were collected to measure oxygen uptake (VO2) and carbon dioxide production, while heart rate was also monitored. The results indicated that fat utilization was maximal at higher heart rates, whereas carbohydrate utilization decreased with increasing heart rate and power. The findings align with previous research, highlighting the inverse relationship between fat utilization and maximal oxygen uptake, and the detrimental effect on carbohydrate utilization with increased heart rate. The study acknowledges a limitation in not considering hormonal effects on substrate utilization, with energy outflow and the two factors of the study related by indirect calorimetry. The report includes graphical representations of VO2 max versus fat utilization and heart rate versus carbohydrate utilization, supporting the analysis.

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Calculation of fat and carbohydrate utilization during incremental
exercise
Introduction
Exercise builds muscle power in the human body to organize the energy. Utilization of this
energy helps human body to function properly. Incremental exercise effects on muscles were
earlier studied by Juul Achten, Michael Gleeson and Asker E. Jeukendrup in 2002. Fat and
carbohydrate are two essentials of our body and their utilization becomes very important for
generating energy (Overmyer, K. A. et al., 2015). These two substrates get oxidized mutually but
comparative input depends on various factors. Effect of incremental exercise has been studied
here.
Method
Four healthy male partakers (average age 19.75 years, S.D 1.7 years; average height 180.4 cm,
SD 10.37 cm; average weight 80.75 kg, SD 12.26 kg) embraced an experiment to cycle on an
ergometer (T4 Alpha 150, Bolton Stirland fitness, Finland) for four set of activities. Activities
started with rest time followed by gradual power increase of 60W, 90W and 120W. Breathed out
gases were collected at the end of each session by the help of Servomex 1440 gas analyzer
(Servomex Plc, Cranlea, USA) where gas volume and percentage exhaled oxygen and carbon-
dioxide in the last 60 seconds of the tasks were measured (dry gas meter, Harvard, Cranlea, UK).
The heartbeat of the subjects was measured by heart rate monitor (Polar, Bodycare, UK). Fat and
carbohydrate utilization for four subjects were found. For that purpose Oxygen uptake (VO2),
CO2 uptakes were calculated. Oxygen uptake maximum level with maximum heart rates was
used to evaluate fat and carbohydrate utilization factors. Average figures of four partakers were
considered for the study purpose.
Results
The experiment started with rest on bicycle ergometer. Three following states of increased work
power affected the utilization factors. Fat utilization was at minimum for 55.10% at average
heart rate of 71.5 beats per minute (bmin-1) and maximum at 80.38% for 138 heart beats per
minute. Carbohydrate utilization factor was 44.89% at 71.5 heart beats and was 19.62% at 138
(bmin-1). The average heart beat rate was 194.17 (bmin-1) with S.D of 1.19 (bmin-1). The VO2

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max versus fat utilization graph has been provided in figure1 and heart rate versus carbohydrate
utilization graph has been put in figure 2.
Figure 1: V02 max versus fat utilization
Figure 2: Heart rate versus carbohydrate utilization
Summary
The fat utilization was at maximum for highest heart rate whereas Carbohydrate utilization
decreased with increment in heart rate due to increase in power. The results were in support of
earlier research works (Halson, S. L et al., 2015). The experimental results were in terms with
the research outcomes of B.Egan, et al., 2015. Similar research work was earlier done by
determining fat oxidation for both the genders by Michelle C. et al., 2005. The inverse relation of
fat utilization with uptake maximum oxygen and detrimental carbohydrate utilization with heart
rate were two important results of the experiment. Major shortcoming was that, hormonal effects
were not considered on the substrates. Energy outflow and two factors of the study were related
by indirect calorimetry.

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References
Achten, J., Gleeson, M. I. C. H. A. E. L., & Jeukendrup, A. E. (2002). Determination of the
exercise intensity that elicits maximal fat oxidation. Medicine and science in sports and
exercise, 34(1), 92-97.
Egan, B., Ashley, D. T., Kennedy, E., O'connor, P. L., & O'gorman, D. J. (2016). Higher rate of fat
oxidation during rowing compared with cycling ergometer exercise across a range of exercise
intensities. Scandinavian journal of medicine & science in sports, 26(6), 630-637.
Halson, S. L., Lancaster, G. I., Achten, J., Gleeson, M., & Jeukendrup, A. E. (2004). Effects of
carbohydrate supplementation on performance and carbohydrate oxidation after
intensified cycling training. Journal of applied physiology, 97(4), 1245-1253.
Overmyer, K. A., Evans, C. R., Qi, N. R., Minogue, C. E., Carson, J. J., Chermside-Scabbo, C.
J., ... & Burant, C. F. (2015). Maximal oxidative capacity during exercise is associated
with skeletal muscle fuel selection and dynamic changes in mitochondrial protein
acetylation. Cell metabolism, 21(3), 468-478.