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Sports Nutrition > Caffeine W10 > Flashcards

Caffeine W10 Flashcards

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Sports Trivia flashcards
1
Q

Where is caffeine metabolised?

A

The liver

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2
Q

What is caffeine?

A

1,3,7-trimthylxanthine

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3
Q

When do peak blood caffeine concentration occur?

A

Typically occurs 60min after ingestion in a dose-dependent way

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4
Q

What are the effects of caffeine?

A

Improved vigilance and alertness

Reduced perception of effort

Reduced fatigue and pain

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5
Q

What is the number 1 mechanism of caffeine? (Central Effect)

A

When adenosine binds to its receptor, this causes fatigue. Caffeine prevents adenosine binding and thereby delays fatigue

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6
Q

What is the number 2 mechanism of caffeine? (Metabolic effect)

A

Caffeine stimulates lipolysis (breakdown of triglycerides), directly and via an increase in adrenaline. This may spare muscle glycogen

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7
Q

What is the number 3 mechanism of caffeine? (Muscle ion effect)

A

Caffeine stimulates calcium release which is important for muscle contraction

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8
Q

How does caffeine increase calcium release in muscle?

A

Caffeine increases the release of intramuscular calcium ions (Ca2+), responsible for muscle contractions, although this seems to happen with very high doses of caffeine

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9
Q

How does caffeine increase fat metabolism and oxidation?

A

Caffeine can directly (increase triglycerides breakdown) or indirectly (increase epinephrine)

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10
Q

Does caffeine and carbohydrate co-ingestion work in influencing substrate metabolism?

A

No- there is no effect on substrate metabolism

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11
Q

How does caffeine block adenosine?

A

The MAIN MECHANISM

Caffeine has similar chemical structure to a molecule called adenosine (responsible for feelings of tiredness, fatigue and even pain sensation)

Therefore, caffeine can stop adenosine from binding to its receptors in the brain, reducing the sensations of both tiredness and pain

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12
Q

What is an advantage of using caffeinated gum?

A

Most of the caffeine bypasses the gut
- increases absorption
- decreases GI distress

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13
Q

What is the optimal dose of caffeine to enhance athletic performance?

A

3mg/kg BM

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14
Q

When should you consume caffeine to enhance performance?

A

40-60min prior

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15
Q

How much caffeine should you ingest doing exercise?

A

1.5mg/kg

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16
Q

How much caffeine should you ingest during late stages or important stages of exercise?

A

100-200mg

17
Q

What is co-ingestion with CHO like?

A

Ergogenic

17
Q

When should you consider caffeine usage?

A

Endurance sports (>60mins)

Brief sustained high-intensity sports (1-60min)

Team and intermittent sports- work rates, skills and concentrations

Single efforts involving strength or power

Pre-training energy boost if carrying fatigue into a session

18
Q

How can caffeine influence hydration?

A

Small to moderate doses of caffeine have minimal effects on urine losses or overall hydration in habitual caffeine users

18
Q

What are the side effects of caffeine?

A

At moderate and high doses of caffeine (>6-9mg/kg) other side effects can occur
- Jitters
- Insomnia
- Inability to focus
- GI unrest
- Irritability

There is a dependency to caffeine- anxiety and sleep disorders, withdrawal effects can occur

19
Q

What are the recommendations for caffeine?

A

The ergogenic effects of caffeine are supported by scientific research, and it is not in WADA’s prohibit list

There is evidence that caffeine (3mg/kg BM) can enhance performance in a range of different sports

High doses can cause negative side effects including gut upset, confusion, anxiety and disturbed sleep (time!)

Generally safe to use, although it varies across individuals. Practical considerations: dose, timing, product, event

20
Q

What is the half-life of caffeine?

A

4-6hours

21
Q

Why is there no effect on substrate level metabolism when caffeine is consumed ?

A

Due to insulin being more prominent and stronger effector when consumed with carbohydrate
May have an effect in a fasted state

22
Q

When does caffeine habitual consumption affect ergogenic effects?

A

6mg/kg BM

23
Q

How much caffeine should children <18 limit to?

A

<2.5mg/kg/day

24
Q

What is a safe dose of caffeine to ingest?

A

400mg/day from all sources and 200mg at any one time

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