Why does rer increase

RQ and RER are two different scientific methods of measuring the type of metabolic fuel the body is using to produce energy.

RQ is a direct measurement taken from the blood and RER in an indirect measurement taken through the breath. Steady state exercise is activity that achieves a balance between the energy required by working muscles and the rate of oxygen and delivery for aerobic ATP production. It has to beat a steady rate, or it will change from being steady state exercise to being anaerobic or high level aerobic exercise.

EPOC refers to the elevation in metabolism rate that calories are burned after an exercise session ends. The increased metabolism is linked to increased consumption of oxygen, which is required to help the body restore and return to its pre-exercise state. What is the respiratory exchange ratio RER? Explain how it is used to determine the oxidation of carbohydrate and fat. The value can vary depending on the type of fuel being used.

VO2 During Exercise Since the ATP energy used by your muscles is generated with the aid of oxygen, it follows that an increase in exercise intensity will result in an increase in muscular oxygen demands. Therefore, increased exercise intensity ultimately corresponds to an increased VO2.

The increased metabolism is linked to increased consumption of oxygen, which is required to help the body restore and return to its pre-exercise state. What is an RQ value? Most energy sources are food containing carbon, hydrogen, and oxygen. Examples include fat, carbohydrates, protein, and ethanol. What is maximal exercise? Why is respiratory quotient important? The respiratory quotient RQ measures the ratio of the volume of carbon dioxide Vc produced by an organism to the volume of oxygen consumed Vo.

This quotient is useful because the volumes of CO2 and O2 produced depends on which fuel source is being metabolized. What is a metabolic cart? The metabolic cart essentially measures the oxygen consumed and the carbon dioxide produced by the patient and then calculates using the modified Weir equation the energy expenditure for the patient.

Why does vo2 increase during exercise? The independence of associated variables on RER was evaluated with multiple regression analysis and the best model was selected by allpossible regressions procedure. Statistical analyses were conducted with SAS System software, version 8. As expected, all the physical fitness variables: body fat, VO 2max , workload max and lactate threshold measured as watts and VO 2 were significantly different in trained subjects compared to untrained Table 1.

No differences in food intake and percentage of macronutrients composition were observed between the groups Table 2. Although the trained subjects were working at higher workload intensity Table 3 and VO 2 at any SEFW, lower lactate concentrations and lower RER values were observed in them compared to those in untrained subjects Fig. O 2 uptake VO 2 during submaximal exercises in endurance trained and untrained men. Open circles, untrained subjects; solid circles, trained subjects.

The tests durations were 4. LT: lactate threshold. VO 2 values are means of one minute taken at the initiation of exercise 1 , at the middle of the test 2 and at the end of the test 3.

Respiratory exchange ratio RER values during submaximal exercises in endurance trained and untrained men. RER values are means of one minute taken at the initiation of exercise 1 , at the middle of the test 2 and at the end of the test 3. Correlation matrix for fasting RER during exercise at different fixed workload intensities on both groups.

Trained and untrained groups were analyzed as a single group. Multiple correlation analysis. Multiple regression analysis was performed to determine any independent association of RER with the aforementioned variables. Multivariate analysis for fasting RER during exercise at different fixed workload intensities on both groups.

Multiple regression analysis. In the present study, we assessed the RER in trained and physically active untrained fasted men exercising at three different submaximal intensities. Trained subjects, exercising at higher absolute workloads, showed significant lower RER values, higher VO 2 , and lower blood lactate concentrations than untrained subjects. The differences in relative intensity at below LT and within LT may not be statistically significant due to the subject response variability, but the differences are large enough to be physiologically significant.

The lower RER values mean that during submaximal exercise, trained subjects oxidized a greater proportion of lipids at higher workload than untrained subjects Messonnier et al. Similar differences, at lower intensities, in RER between trained and untrained subjects have been previously found Bergman and Brooks, The lower blood lactate concentrations means, that the trained subjects had a more active lipid oxidative metabolism.

There was an increase in blood lactate concentration during submaximal exercise, even below LT, in spite of the workout was constant and the VO 2 did not show any significant change. Our results are in agree with those of Bearden et al. Therefore, increases in blood lactate concentration could be detected without the increase in minute ventilation, induced by the hydrogen ions. The cross-sectional design of the present study precludes any conclusion regarding the possible mechanisms by which endurance training may lower RER.

In longitudinal studies, a decrease in RER has been observed after training at the same absolute workload but not at the same relative intensity Friedlander et al.

Such biochemical changes drive fatty acid oxidation, which would be reflected as a decrease in RER value. Consequently, such enzyme synthesis promoted an increase in fatty acid oxidation and, therefore, a decrease in RER values. On the other hand, physical training also increases the buffer capacity of blood Juel, which could contribute to the decrease in the RER values in trained subjects.

In our study, the RER evaluations were carried out after 10 to hours of fasting under a controlled temperature, a similar diet and a similar caloric balance; therefore all these variables could not have influenced our results. Both obesity and insulin resistance also modify the RER during exercise Goodpaster et al. In our study, only healthy physically active subjects, with low body fat, were included. The RER decreases at the end of the exercise are indicative of both, a shift towards lipid metabolism Bier and Young, and a lower compensatory hyperventilation to lactic acidosis.

Multiple correlation analysis showed a systematic association between RER at any SEFW and physical fitness variables body fat, maximum heart rate, VO 2max and lactate threshold. The association of the RER with variables of physical fitness, like anthropometric characteristics, VO 2max and lactate threshold, has not been clearly established.

Goedecke et al. Nevertheless, through a multivariate analysis, they determined that the training volume is responsible for the changes on RER values at rest and during exercise.

In addition, these authors found that citrate synthase activity, an indicator of aerobic capacity, had an influence on the RER values during exercise. Based on these data, Goedecke et al. The present work strengthens these results. Since, as reported by Goedecke et al. In addition, acute exercise affects lipid oxidation Jamurtas et al. Maximal incremental exercise testing is the gold standard in the cardio-respiratory fitness assessment and provides a wealth of clinically diagnostic and prognostic information Whaley, ; however, not all people can do it Vanhees et al.

The results of the present work suggest the possible application of RER during submaximal test at below LT intensities, and being an useful metabolic fitness indicator in special populations and subjects with reduced exercise tolerance.

For that reason, the LT or VO 2max should not be necessary because, as independent parameter is only necessary work at one submaximal and confortable intensity. However, because of we have not tested a specific population in this study; this proposal should be taken with caution but deserves future validation. For the above mentioned, since the accurate quantification of physical activity becomes essential in determining the health status, and in evaluating the intervention programs effectiveness Whaley, , the evaluation of health-related physical fitness, besides of body composition, muscular strength, flexibility, and cardio-respiratory measurements, has to include the total oxidative metabolism assessment measured as RER.

So you can imagine the negative impact of a prolonged period of time in a calorie deficit, while sleep deprived. The study highlights that a lack of sleep may shift substrate utilisation away from fat when at rest. So the lesson here is make sleep a priority if you want to burn fat, rather than muscle.

RER isn't something you need to concern yourself with on a daily basis. Sticking to the basics of managing calories, exercises, and recovery will ensure RER takes care of itself. When it comes to RER, managing the basic of training and nutrition will always be the best course of action.

There's no need to overcomplicate the process and disappear up your own ass by trying to manipulate substrate utilisation unless you're a pro endurance athlete. In reality, if your goal is weight and fat loss, your focus should be on the basics; eat in a sustainable calorie deficit, exercise regularly, maximise sleep, and eat a diet high in nutritious, whole foods. Do that, and RER will take care of itself and work in your favour. There's certainly no need to train fasted or follow a high fat diet, unless you want to.

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