Respiratory Exchange Ratio

Respiratory Exchange Ratio (RER)

Introduction:

Three students representing each meal class was tested on the Jaeger Oxycon breath by breath analyser at baseline(sitting down), while walking(low intensity) and while running( high intenstity) for 3 minutes each. During this time the RER reading was recorded every 30 seconds.

Questions:

1. Protein is the last source of energy metabolism. Proteins are only broken down in fasting conditions when all the fat and glucose( from carbohydrate digestion)are used. The oxidative system (aerobic) is the primary source of ATP supplied to the body at rest and during low intensity activities. At rest, about 70% of the ATP is produced from fats and 30% of carbohydrates, but after the start of the activity, thus an increase of the intensity of an exercise, a shift from fats to carbohydrates is observed(Holloszy, Kohrt, & Hansen, 1998 ).

2.

Figure 1: Respiratory Exchange Ratio (RER) of high Carbohydrate, Fat and Protein for different exercise intensities over a period of time(seconds).

3. I would choose the 20% glucose containing beverage including electrolytes, due to the fact that glucose metabolism uses less oxygen per glucose consumption as an energy source. Different sources of food respiration coefficients(RQ) could explain why I made this choice.

Glucose respiration coefficient:

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O thus RQ = 6 CO2 / 6 O2 = 1.0

Palmitic acid(Fat) respiration coefficient(Holloszy et al.,1998 ):

C16H32O2 + 23 O2 → 16 CO2 + 16 H2O thus RQ = 16 CO2 / 23 O2 = 0.696

Albumin(Protein) respiration coefficient:

C72H112N18O22S + 77 O2 → 63 CO2 + 38 H2O + SO3 + 9 CO(NH2)2 thus

RQ = 63 CO2/ 77 O2 = 0.818

Glucose is the best food source to use in endurance running, because there is constant energy at minimal oxygen consumption for use(Brooks & Fahey, 1984). The 8% glucose drink have less glucose than the 20%. The electrolytes are also important because they are what your cells(namely nerve, heart and...