W6 - Ergogenic Aids - Nitrate

Question 1

Via what pathway is nitric oxide synthesised in the body?

Answer 1

L-arginine pathway

Question 2

What does the L-arginine pathway require?

Answer 2

Arginine

O2

NADPH

Question 3

What does the L-arginine pathway produce?

Answer 3

NADP

Citrulline

NO

Question 4

What are the 3 forms of NOS?

Answer 4

NOS1 / nNos

NOS2 / iNOS

NOS3 / eNOS

Question 5

When NO is produced in the CV system…

How does it enter the smooth muscle of the bv?

Answer 5

Diffuses from endothelial cell to the smooth muscle of the bv.

Question 6

When NO is produced in the CV system…

What happens once NO has entered the smooth muscle of the bv?

Answer 6

Activates sGC

Question 7

When NO is produced in the CV system…

What is the result of sGC being activated by the NO?

Answer 7

Incr cGMP

Question 8

When NO is produced in the CV system…

What is the result of the activated sGC increases cGMP?

Answer 8

Activation of protein kinase (PKG)

• Results in decr Ca2+ via at least 4 mechanisms

Question 9

When NO is produced in the CV system…

What are the 4 mechanisms by which ca2+ is decreased after PKG is activated?

Answer 9

Inhibition of voltage gated channels

Activation of plasma membrane calcium ATPase (PMCA)

Inhibition of IP3R

Activation of SERCA

Question 10

When NO is produced in the CV system…

NO activates sGC.

= Incr cGMP

= Activates PKG

= Decr Ca2+ via 4 mechanisms

What do all these mechanisms result in?

Answer 10

Relaxation of vascular smooth muscle cells.

Question 11

Process of digestion for dietary nitrate

Answer 11

Ingested

Absorbed into systemic circulation

Conc in saliva where oral bacteria can prod nitrite.

Nitrite is swallowed –> Stomach to be converted to NO + support host defence OR nitrite can be absorbed into systemic circulation again + who needed can be converted to NO.

Question 12

Dietary nitrate supplementation and low intensity exercise

Answer 12

Red the O2 cost

Question 13

Dietary nitrate supplementation and high intensity exercise

Answer 13

Enhances tolerance

Question 14

Nitrate supplementation and time to exhaustion

Answer 14

Increased ~16%

• BUT not an ecologically valid measure of exercise performance.

Question 15

Nitrate supplementation and rowing performance

Answer 15

NO sig improvement according to a meta-analysis

Question 16

Beetroot juice ingestion and 10km TT performance

Answer 16

Incr power output

Question 17

Nitrate supplementation and CWR bouts

Answer 17

O2 uptake is reduced

Question 18

Nitrate supplementation and intermittent type exercise

Answer 18

Might have beneficial perf effects

Question 19

When is the L-arginine -NO pathway blunted?

Answer 19

During hypoxia

Question 20

Why would improved reaction time in the 2nd half of an intermittent sports game be beneficial?

Answer 20

Allows 1 to react quickly to changing stimuli

Question 21

Nitrate supplementation and marathon

Answer 21

There are benefits

Question 22

NO metabolism and menstrual cycle

Answer 22

It is known to be differences in its metabolism throughout the menstrual cycle

Question 23

What is the minimal effective acute dose that may be required to gain an advantage from nitrate in a mixed population?

Answer 23

5mmol

Question 24

VO2 during 75W clamped protocol and nitrate supplementation

Answer 24

Sig altered

Question 25

When is the change after supplementing dietary nitrates more pronounced, when you start with a higher or lower aerobic fitness?

Answer 25

Lower

Question 26

Why might elite endurance athletes have a reduced effect from nitrate?

Answer 26

Higher NOS activity Higher baseline plasma [nitrite] Better muscle oxygenation therefore L-arginine NO pathways always active due to amounts of O2 present. Higher mit vol + efficiency Nitrate dose + duration of supplementation may not be optimised for them Higher proportion of type 1 fibres which may not be as responsive to nitrate supplementation

Question 27

What seems to be a deciding factor of the lack of ergogenic effect from nitrate supplementation in athletes?

Answer 27

Aerobic capacity

Question 28

Which type of athletes seem to experience ergogenic effects from nitrate supplementation?

Answer 28

Power + sprint

Question 29

What is the most ecologically valid performance measure of endurance performance in sport?

Answer 29

TT

Question 30

65+ ml/kg/min does not have a significant overall effect for nitrate supplementation + performance. True or false

Answer 30

True

Question 31

With regards to nitrate supplementation... As aerobic capacity increases, what happens to TT performance improvements?

Answer 31

Decrease

Question 32

What is meant by mitochondrial oxidative phosphorylation efficiency?

Answer 32

Amount of O2 consumed per ATP prod

Question 33

Which type of muscle fibre seems to be affected the most by nitrate supplementation?

Answer 33

Type 2

Question 34

What is believed to increase with nitrate supplementation?

Answer 34

Ca2+ sensitivity SR Ca2+ pumping

Question 35

What was the surname of the first author to show nitrate lowers VO2 during submaximal exercise?

Answer 35

Larsen

Question 36

What effect does nitrate supplementation have on high intensity time to exhaustion?

Answer 36

Increases time to exhaustion

Question 37

When considering the meta-analysis, which of the following does not have a significant improvement in performance with nitrate supplementation? Running Cycling Handgrip Rowing

Answer 37

Rowing

Question 38

Which nitric oxide metabolism pathways is blunted during hypoxia?

Answer 38

Nitrate-nitrite-nitric oxide pathway

Question 39

In the meta-analysis, which aerobic capacity does not have a significant overall effect for nitrate supplementation and performance?

Answer 39

65+ ml/kg/min

Question 40

Which of the following do we believe increases with nitrate supplementation? Calcium sensitivity Calcium concentration Sarcoplasmic reticulum calcium release Sarcoplasmic reticulum calcium pumping

Answer 40

Calcium sensitivity Sarcoplasmic reticulum calcium pumping

Question 41

What enzymes is vital for the L-arginine pathway?

Answer 41

Nitric oxide synthase

Question 42

What can oral bacteria do to NO3- from the diet?

Answer 42

Convert it to NO2-

Question 43

What happens to the nO2-

Answer 43

To the stomach, Some enters systemic circulation Some converted to NO.

Question 44

What happens to O2 uptake after nitrate supplementation for CWR bouts?

Answer 44

Decreases