B3L8 Acid-Base Regulation

What happens to VO2 max at altitude?

Decrease

VO2max = CO2 x (a-v) x O2

Why does VO2 max decrease at altitude?

1. HR decreases dramatically

2. SV also decreases

Why is training at high altitude not a good idea for overall training?

Because you are working the same relative intensity for lower absolute power

What are obstructive respiratory disease?

Increased RESISTANCE to airflow due to decreased diameter

• asthma

• bronchitis

• COPD

Restrictive respiratory disease

Decrease lung volumes

• fibrosis

• pneumothorax

• respiratory distress syndrome

• pulmonary edema

• tumor

what is the FEV_1.0?

The measured amount of forced air exhaled after one second

What would a normal FEV calculation be?

80% of your total max exhale should be after 1 second

How do you calculate FEV?

FEV1/FVC

• 80% = normal

• >80% = restrictive lung disease

• <80% = obstructive lung disease

Why are mediators harmful in the context of bronchospasms?

Because they bind to mast cells, which cause inflammation and decrease cAMP

What do bronchoconstrictors do?

Act on the respiratory muscles to decrease cAMP which regulates contraction

• decreased cAMP increases bronchospasms

In what conditions is exercise-induced asthma most common?

Dry, cold air

What are the two theories for what causes exercise-induced asthma?

1. Hyperosmolar theory: dry cold air causes water loss, making tissues hyperosmolar and increases inflammatory response

2. Airway rewarming theory: more warming is necessary which causes bronchodilation which increases the flow of mediators (decrease in cAMP)

how do you calculate pH?

pH = -log[H+]

Low pH, high H+

Acidosis

High pH, low H+

Alkalosis

What mechanisms does the body have to decrease acidity?

1. Buffer systems

2. Shift the carbonic anhydrase rxns towards CO2'

3. Renal compensation (more erythropoetin)

At rest, [HCO3-] = ___

24mMol

What kind of relationship do HCO3- and lactate have?

Inversely proportional

Lactate lvls = 18mMol. What is HCO3-?

24 - 18 = 6mMol