BGZ2025 Practical Indirect Calorimetry Presentation Powerpoint and Notes (text used
during the presentation)
At the end of the document also the preparations for the 2 meetings
CPET for a female triathlete and a male strength athlete
Faculty of Health, Medicine and Life Sciences
Health Sciences, BGZ Year 2
Names and student numbers
➢ VO2 max test
➢ Indirect calorimetry
➢ Objective practical
• Intensity ↑ → Substrate turnover + energy expenditure ↑
VO2 max test
The VO2 max test is an exercise test on a treadmil or bicycle ergometer. The purpose
of the VO2 max test is to analyze your breath. During the VO2 max test, the
intensity/workload is gradual y increased until there is a steady reading. VO2 max is
defined as the maximal oxygen uptake and therefore it measures the condition. The
higher the VO2max, the more energy is produced by using oxygen and the more
talent for endurance sport. Indirect calorimetry
The indirect calorimetry is a method to measure the energy expenditure: oxygen
consumption (O2 concentration) and carbon dioxide production CO2
(concentration). Measurement of energy expenditure is important in order to
determine basal metabolic rate and inform energy prescription provided.
Indirect calorimetry systems estimate respiratory gas exchange as a surrogate for
substrates consumed and produced during metabolism. This is done by one of 4
methods: confinement, closed-circuit, total collection, and open-circuit approaches.
In this practical, the open-circuit system is used (flow of air measured either on the
inlet or outlet side of the subject).
There are some considerations when using the indirect calorimetry. The participant
should be at rest, with last endotracheal tube suction done at least 20 min before the
measurement, no ventilatory changes, and minimal change in medications (if
applicable) administered for the hour prior. Continuous enteral and parenteral
nutrition should be continued.
Limitations of the indirect calorimetry are the high monetary costs to purchase and
maintain the equipment and the time cost to perform the measurement. Objective + hypothesis of the practical
The aim of the practical is to establish the relationship between exercise intensity and
substrate oxidation and energy expenditure. Therefore, analysis wil be done for two
different subjects. The analysis is focused on some parameters: the heart rate,
VO2max, RER/RQ, blood pressure, pulmonary ventilation and the ventilatory/lactate
The hypothesis is that when the intensity increases, the energy expenditure wil also
increase (because more energy is needed for circulating blood, breathing etc.).
Furthermore, when the intensity increases it also influences the substrate oxidation.
(Endurance) exercise wil lead to a substrate turnover: while first using anaerobic
energy system, on long-term the aerobic energy system (carbohydrate and fat
oxidation) wil play a role (Philips, et al., 1996).
● Protocol: CPET ramp protocol
-T0 = 0 Watt
-Increase with 25.5 and 30 Watt/min
-End when exhausted
• Characteristics of the test persons:
One test person is a male of 27 years. He has a height of 164 cm and a weight of
69 kg. He is a strength athlete and performs 4 training sessions per week which
comes down to 6 to 9 hours per week. His fitness level is moderate to good.
The other test person is a female of 19 years. She has a height of 157 cm and a
weight of 54 kg. She is an elite triathlete and trains 25 to 30 hours per week. Her
fitness level is excel ent. • Protocol:
The performed test was a cardiopulmonary exercise test (CPET), which is a
maximal exercise test performed with the ramp protocol. CPET has become an
important clinical tool to evaluate exercise capacity and predict outcomes in
cardiac conditions and the determination of functional capacity and impairment
(Albouaini, Egred, & Alahmar, 2007). It provides assessment of the integrative
exercise responses involving the cardiovascular, respiratory and skeletal muscle
systems. The starting value is 0 Watt and every 2 seconds the workload is gradually
increased with 1 Watt. This results in an increase of 30 Watt per minute. The test