HRV + dyslipidaemia Flashcards

1
Q

What are the neurotransmitters of the SNS and PNS?

A

SNS:
presynaptic - acetylcholine
postsynaptic - noradrenaline

PNS:
presynaptic - acetylcholine
postsynaptic - acetylcholine

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2
Q

HR is a balance between … and … activity

A

PNS

SNS

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3
Q

Additional SNS pathway:

A

Adrenal pathway with adrenaline released from adrenal medulla

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4
Q

Which parts of the heart does the PNS innervate?

A

Atria
SAN
AVN

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5
Q

Which parts of the heart does the SNS innervate?

A

SAN
AVN
Atria
Ventricles (inotropic effect)

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6
Q

Name the 2 receptors involved in the PNS pathway

A

Presynaptic - nicotinic

Postsynaptic - muscarinic

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7
Q

5 effectors of autonomic nervous system

A
Smooth muscle
Cardiac muscle
Exocrine glands/cells
Some endocrine glands/cells
Some adipose tissue
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8
Q

Post synaptic receptors of SNS include … and …-receptors

A

alpha

beta

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9
Q

Pacemaker cells of heart have membrane potentials … than that of cardiac muscle cells with naturally … membranes allowing … depolarisation to threshold producing an AP

A

lower
leaky
spontaneous

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10
Q

SNS … HR and increases …

A

increases

strength of contraction

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11
Q

Pacemaker membrane potential is usually …

A

-60mV (versus -80 to -90mV for other cardiac cells)

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12
Q

Describe the process of SNS increasing HR

A
  1. Increased SNS tone
  2. Increased adrenaline and NA
  3. activation of beta-receptors and increased calcium (and Na+) influx into myocardial cells
  4. Depolarisation threshold reached quicker –> increased HR
  5. Increased calcium availability –> increased contraction force
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13
Q

The … of calcium from … is important for the speed of contraction

A

undocking

troponin

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14
Q

The SNS causes a … forceful contraction with a … duration

A

more

shorter

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15
Q

With a slower HR (predominantly PNS), there is a … depolarisation with …

A

slower

hyperpolarisation

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16
Q

With a faster HR (predominantly SNS), there is a … depolarisation with … repolarisation

A

rapid

reduced

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17
Q

Describe the process of PNS decreasing HR

A
  1. Increased vagal tone
  2. Increased ACh release
  3. Increased outflow of K+ from cells and decreased calcium influx leading to hyperpolarisation of myocardial cells
  4. Depolarisation threshold reached more slowly
  5. decreased HR
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18
Q

Beta-1 receptor main location and effects:

A

Myocardium:

Increases HR, increases contractility

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19
Q

Beta-2 receptor main locations and effects:

A

Bronchiolar and arterial smooth muscle:
Relaxation of bronchial smooth muscle
Arteriolar dilation

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20
Q

Differential effect of cardiac SNS fibres: left fibres have a greater effect on …; right fibres have a greater effect on increasing …

A

contractility

HR

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21
Q

The intrinsic HR of the heart is …

A

100bpm

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22
Q

As exercise intensity increases, there is more … control of HR

A

sympathetic

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23
Q

In a study, participants were given propranolol (Beta-blocker) then atropine and vice versa: what HR response would you see?

A

Initial HR decrease with propranolol, then increase with atropine to reach intrinsic HR (as both receptors blocked)

Initial increase of HR with atropine, then decrease to intrinsic HR with propranolol as both SNS and PNS receptors blocked

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24
Q

Mean HR is an … rate over one minute, sometimes the HR will be faster and other times are slower

A

average

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25
Q

Demands of the body for HR response:

A
Respiration
BP control
Temperature control
Delivery of O2 and removal of wastes
Hormonal influences
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26
Q

HR variability on breathing:

A

Breathe out: slows down HR (PNS nerves inhibited)

Breathe in: speeds up HR (PNS nerves fire)

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27
Q

During a slower HR with more … influence, there is … variation between heart beats

A

PNS

more

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28
Q

During a quicker HR with more … influence, there is … variation between heart beats

A

SNS

less

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29
Q

Advantages of greater HR variability (3)

A

So the body can vary HR with all the demands

Variation reflects a healthy vagal system

Lack of variation indicates SNS predominance - hyperpolarised membrane with increased arrhythmia risk

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30
Q

3 ways neurotransmitters are usually removed from synapse

A

Enzymes break them down

Diffusion away from cell

Transport into cells

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31
Q

Why is the PNS system more variable?

A

ACh effects are very short lived due to the abundance of acetylcholinesterase in the heart clearing away ACh.
The HR is only temporarily slowed and HR increases back toward intrinsic HR and another ACh is released.

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32
Q

Why is the SNS system less variable?

A

Noradrenaline is cleared from synapses by re-uptake into neurone, or by diffusion away from cell into blood.

This is a much slower process with longer lasting effects on HR

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33
Q

At rest, HR is … with a … predominance, but has … variation

A

slower
PNS
greater

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34
Q

How does blood pressure control affect HRV?

A

Angiotensin increases SNS tone increasing BP and decreasing variability

Baroreceptors increase BP with increased vagal tone thereby decreasing HR and increasing HRV

35
Q

Decreased temperature … SNS tone, causing vaso… and … HRV

A

increases
constriction
less

36
Q

How does hypoxia, hypercapnia or acidosis affect HR and HRV?

A

Increases HR but decreases HRV

37
Q

How does the Bainbridge reflex affect HRV?

A

Increases SNS increasing HR and decreasing HRV

38
Q

2 time domain methods of measuring HRV

A

SDNN: standard deviation of all RR intervals; the bigger the deviation the better = shows more variation in HR.

NN50: number of pairs of adjacent RR intervals differing by more than 50ms; the more the better = more PNS tone

39
Q

If one cycle takes 5 seconds (12/min), what would the frequency be?

A

(1/5 cycle)/second = 0.2 Hz

40
Q

What do frequency domain methods of measuring HRV involve?

A

Using frequency power spectrum charts and identifying the frequency (in Hz) of spikes on graph

41
Q

What are the high frequency modulation (0.2Hz) peaks in frequency domain methods due to?

A

Fluctuations every 2.5-7 seconds caused by:
Ventilation,
PNS modulation

42
Q

What are the low frequency modulation (0.04-0.15 Hz) peaks in frequency domain methods due to?

A

Fluctuations every 7-25 seconds caused by:
BP control,
chemoreceptor control,
PNS/SNS modulation

43
Q

What are the very low frequency modulation (0.0033-0.04 Hz) peaks in frequency domain methods due to?

A
Fluctuations every 25 seconds to 3 minutes caused by:
Thermoregulation,
Renin-angiotensin system,
Catecholamines,
Sympathetic modulation
44
Q

In light/moderate exercise, … tone is withdrawn … HR.

A

PNS

increasing

45
Q

In moderate/heavy exercise, … tone dominates causing increased … and … effects

A

SNS
chronotropic
inotropic

46
Q

When sleeping, there is … dominance, with … variance of HR. There is enhanced … activity immediately after waking

A

PNS
Increased
SNS

47
Q

People with CHD have … HRV.

A

decreased

48
Q

Little HRV is reflective of a predominance of … tone

A

SNS

49
Q

Saturation of SNS tone can lead to …

A

arrhythmias

50
Q

HRV … with … age

A

declines

increasing

51
Q

True or false, aerobically trained individuals have less HRV than sedentary peers?

A

False - they have greater HRV

52
Q

Endurance training can … HRV

A

increase

53
Q

More HRV causes more … tone and therefore a … resting HR

A

PNS

lower

54
Q

Why does training decrease resting and exercise HR?

A

Decreased SNS activity due to:
lower sensitivity and number of beta receptors in heart
lower adrenaline release during submax exercise
lower SNS component of arterial baroreflex control of HR

Increased vagal activity due to:
prolongation of AVN conduction time due to hyperpolarisation caused by increased vagal tone

Decreased intrinsic HR

55
Q

How does training influence affect SV?

A

Increased blood volume –> more filling time –> greater EDV –> greater Frank-Starling –> greater SV

56
Q

4 roles of lipids in the body

A

Sex hormones - cholesterol (progesterone, testosterone, oestrogen)
Cell membranes
Protection of organs
Thermal insulation

57
Q

What is the function of lipoproteins?

A

To transport lipids in the blood (as lipids are insoluble in blood) to allow binding with cell receptors to enter cells

58
Q

5 types of lipoprotein

A
Chylomicrons
VLDL (triglycerides - cells)
LDL (cholesterol - cells)
HDL
Apolipoproteins - Lp(b) is the carrier molecule for LDL, Lp(a) is carrier molecule for HDL
59
Q

How does HDL clear cholesterol?

A
  1. HDL exchanges a triglyceride for cholesterol with LDL via the enzyme lecithin cholecterol acyltransferase (LCAT)
  2. HDL binds to liver and offloads cholesterol where it is involved in production of bile salts etc.
  3. HDL can also ‘scavenge’ free cholesterol from tissue and transport to liver.
60
Q

What is dyslipidaemia?

A

A poor blood lipid profile

61
Q

What is hyperlipidaemia?

A

Abnormally high levels of cholesterol, triglycerides, or both in the blood (can be hypercholesterolaemia, hypertriglyceridaemia, or both)

62
Q

Dyslipidaemias alone provoke….

A

No physical symptoms (silent disease)

63
Q

2 signs of dyslipidaemias

A
Corneal arcus (rings around eyes)
Tendon xanthomas
64
Q

Ideal cholesterol level

A

<5.2 mmol/L

65
Q

Mildly high cholesterol level

A

5.2 - 6.2 mmol/L

66
Q

Moderately high cholesterol level

A

6.2 - 7.8 mmol/L

67
Q

Very high cholesterol level

A

> 7.8 mmol/L

68
Q

3 dietary interventions of dyslipidaemia

A

Decrease total fat intake to 25-35% of total calories

Reduce saturated fat intake

Increase fibre (reduces LDL)

69
Q

3 pharmacological interventions for dyslipidaemia

A

Bile acid sequestrants - body replaces bile by using LDL to make it, LDL levels drop

Statins - reduces production of cholesterol

Fibric acids - reduce fatty acid uptake by liver

70
Q

True or false, pharmacological interventions for dyslipidaemia have an affect on the exercise response.

A

False - they do not

71
Q

As physical activity levels increase, … concentration increases

A

HDL

72
Q

… of exercise is most important in changing cholesterol profiles, rather than …

A

Volume

intensity

73
Q

… of exercise has most consistent effect on HDL levels

A

Volume

74
Q

Exercise training needs to last … … to show an effect on HDL/LDL profiles

A

12 weeks

75
Q

Minimum intensity threshold for dyslipidaemia is … METS

A

5-7

76
Q

The biggest changes in lipid profiles with chronic exercise training occur in people with … profiles

A

poorest

77
Q

Resistance training effects on dyslipidaemia

A

Small increase in HDL, small decrease in TC, LDL and triglycerides

Higher volume better than higher intensity

Resistance exercise coupled with aerobic for max effect

78
Q

Changes in lipid profile after single exercise session (immediate)

A

18-48hr post:
Decreased serum triglycerides, increased HDL

Increased lipoprotein lipase activity –> increased LCAT activity

79
Q

3 chronic effects of exercise on lipid profile

A

Increased capillary density from training increasing lipoprotein lipase binding sites

Increased lipoprotein lipase activity reducing breakdown of HDL and increase triglyceride usage

Increased LCAT

80
Q

Why is HDL cholesterol more favourably increased after endurance training?

A

Due to increases in LCAT facilitating increased ester transfer to HDL, and increases in lipoprotein lipase activity.

81
Q

What role might HIIT aerobic training have in improving cholesterol profiles?

A

Higher intensity aerobic training will directly reduce LDL-cholesterol and triglyceride levels

82
Q

What %1RM, reps & sets would you prescribe for resistance exercise?

A

Moderate-intensity (50-85% 1RM)

Higher volume of reps/sets will have a greater impact upon lipid profile versus higher intensity.

83
Q

Exercise enhances the ability of skeletal muscles to utilise … as opposed to …

A

lipids

glycogen

84
Q

In order to directly reduce LDL and triglyceride levels, aerobic exercise … must be increased

A

intensity