Chapter 5 Physiology Exam 3 Review FINSIHED

Big point questions: 14, 15, 18, 19, 21

1) Explain The Difference between direct and indirect calorimetry. How do we use each to measure/estimate energy expenditure? What are the pros and Cons Of each

Direct Calorimetry measures heat production an organism directly, while indirect calorimetry estimates total body energy expenditure based on O2 used and Co2 production

What are the pros of direct calorimetry

Accturate over time, good for resting metabolic measurements (BMR, RMR)

What are the cons of direct calorimetry

Expensive slow, exercise equipment adding heat, and also factor of sweat can impact results and product error in measurement

What are the pros of indirect calorimetry

Measures respiratory gas concentrations (volume of expired oxygen, expired co2)

What are the cons of indirect calorimetry

Only accurate for steady state oxidative metabolism (lasting 1 min or longer) and is older

2. What is Vo2 (and how is It found)

Volume of o2 consumed per minute (rate of o2 consumption)

• Found through volume of inspired o2 - volume of expired o2

What is vo2 max

Maximum amount of o2 a person can consume

Measuring Energy Expenditure:
O₂ and CO₂ Measurements:
What is the fraction relationship

•Vo2 inspired > Vo2 expired

• VCO2 inspired < VCo2 expired

3. What does RER stand for (and what is it)

Respiratory exchange ratio

• Is how we calculate the substrate use (how much carbohydrates vs fats a person is using, and how much energy they expend at rest

• Only accurate during steady state exercise

4. How is RER calculated

RER = vco2 produced/vo2 consumed

5. What is a typical RER at rest? What is the primary fuel at rest (multiple choice)

Typical RER = 0.78, the primary fuel is fats

6. What is a typical RER at maximal exercise? What is the primary fuel at max (multiple choice)

Typical RER = 1.0, primary fuel is carbohydrates

7. Why is it possible to see RER values as high as 1.1 — 1.2 during maximal effort?

Because we produce co2 from reactions other than metabolism

8. When is DLW (doubly labeled water) a useful tool to measure EE (Energy expenditure)

Doubly labeled water is useful when we measure EE in free living people of a period of days to weeks

9. What is BMR?

Basal metabolic rate, measuring rate of energy expenditure at rest

10. What is RMR?

Resting metabolic rate

11. Name at least 3 factors that affect RMR

Free fat mass, body surface area, age, stress, hormones, body temperature

12. What is meant by steady state exercise?

REVIEW

13. How long does it take to achieve steady state exercise

2 -5 minutes

14. What is the slow component of O₂ uptake kinetics? At what intensity does it occur? Why Does it happen?

    Definition:  A gradual increase in vo2 despite no change in workload.

Intensity: Above lactate threshold, vo2 will continue to creep up 

Why: Because you start to recruit more type II fibers

14A. What is the definition for the slow component of O₂ uptake kinetics?

A gradual increase in vo₂ despite no change in workload

14B. At What intensity does the slow component of O₂ uptake kinetics occur?

Above lactate threshold, since vo2 will continue to creep up

14C. Why does the slow component of o₂ uptake kinetics happen?

Because you start to recruit more type II fibers

15. What is Vo2 drift? At what intensity does it occur? Why does it happen?

a.     Definition:  A gradual increase in vo2 despite no change in workload.

b.     When: Below lactate threshold, at low to moderate intensity, longer duration

c.     Why: Due to ventilatory or hormonal changes

15A. What is the definition for Vo2 drift?

A gradual increase in vo2 despite no change in workload

15B. At what intensity does Vo2 drift occur?

Below lactate threshold, at low to moderate intensity, longer duration

15C. Why does Vo2 drift Occur?

Due to ventiliatory or hormonal change

16. What is absolute VO2? What are the units?

Vo2 Max measured in L _O2/min

17. What is relative Vo2? What are the units? (multiple choice)

Vo2 Max normalized for body weight, measured in ml_O2/kg/min

18. What is O2 Deficit? (What is it, when does it occur, how is a person able to accomplish the exercise?

a.   when the vo2 required for an exercise is greater than the vo2 consumed

b.     It occurs in the first couple minutes of exercise (early exercise when we increase workload)

c.     If the vo2 isn’t where it needs to be, we rely on anerobic energy production (Phosphagen/glycoltic systems, ATp,Pcr)

18A. What is O2 Deficit?

When the vo2 required for an exercise is greater than the vo2 consumed

18B. When does O₂ deficit occur?

Happens in the first couple minutes of exercise (early exercise when we increase workload)

18C. How is a person able to accomplish the exercise with O2 deficit?

If the vo2 isn’t where it needs to be, we rely on anaerobic energy production (Phosphagen/glycolysis systems, ATP, PcR

19. What is O2 debt? (EPOC) (what is it, when does it occur, what causes it?

a.     When Vo2 remains elevated after exercise

b.     Occurs after exercise

c.     Why does is occur - Occurs replenishing atp/Pcr, converts lacteate to glygoen, repleishenes hemo/myoglobin, clears co2

19A. What is O₂ debt?

When Vo₂ remains elevated after exercise

19B. When does O2 debt occur?

After exercise, it takes some time for everything to come back down (ex Heart rate)

19C. What causes O2 debt?

replenishing atp stores, replenishing PCr, clearing waste products like lactate, replenishing glycogen stores, clearing co2, muscle damage

20. What does EPOC stand for?

Excess post oxygen consumption, determined by the intensity and duration of exercise

21. What are 4 things that causes EPOC?

replenishing atp stores, replenishing PCr, clearing waste products like lactate, replenishing glycogen stores, clearing co2, muscle damage

22. What is lactate threshold?

   a workload (intensity) where lactate production exceeds clearance [→ accumulates in your bloodstream faster than your body can clear and recycle it] . Never reach steady state if you are above lactate threshold

What kind of training do you have to do to improve lactate threshold

must train at locate threshold

Higher lactate threshold =

higher sustained exercise intensity = better endurance performance

23. 1.     LT occurs at _____% VO_2max for untrained individuals and _____%VO_2max for trained individuals. (multiple choice question)

50 - 60 % Vo2 max for untrained individuals, 70-80% for trained individuals

24. What is economy (in terms of performance)?  

Vo2 for a given workload

How does vo2 change at a given workload if we’re more economical

vo2 is going to be lower – it costs less oxygen to do that same amount of work, and because of that you can work at a higher lactate threshold

25. What are the 3 most important characteristics of an endurance athlete?

High vo2 max, high lactate threshold, high economy