Transcript Heart rate response - Mrs King

Heart rate response
Saratha Kugendran
Questions you might have:
• How does the heart rate respond to exercise?
• Does it respond differently to maximal and
submaximal exercise?
• How does the heart rate differ between the rest,
exercise and recovery phases of movement?
REST PHASE
• Anticipatory rise BEFORE EXERCISE due to
ADRENALIN which is released by the
sympathetic nervous system.
• This leads to a decrease in activity of the
PARASYMPATHETIC nervous system.
EXERCISE PHASE
• During exercise, the heart rate increases
rapidly.
• Proprioceptors detect MOVEMENT.
• Production of CO₂ increases blood acidity
which is detected by CHEMORECEPTORS in the
aorta.
• There are increased SYMPATHETIC nerve
stimulations which in turn stimulate the SAN.
RECOVERY PHASE
• The heart rate is INCREASED and this
stimulates BARORECEPTORS.
• There are increased parasympathetic nerve
impulses and therefore decreased
SYMPATHETIC stimulation
• The heart rate is maintained then DROPS
rapidly.
Maximal exercise
A= ANTICIPATORY RISE
B= SHARP RISE
C= HR CONTINUES TO
RISE
E= RAPID DECLINE
F= SLOWER RECOVERY
RATE
What do the letters represent? Discuss with your partner.
On your sheets, write a brief description of each letter.
Now try Submaximal exercise on your
own
A= ANTICIPATORY RISE
B= SHARP RISE
D= STEADY STATE
E= RAPID DECLINE
F= SLOWER RECOVERY
5 MINUTES
Discuss with your partner why the graphs look so different?
Use the words that letters A-F represent, to help you with your answer.
Jun 2001 - Qu 4: Performance may develop as a result of exercise and learning.
(a)(i) Explain what happens to your heart rate prior to exercise
(2 marks)
(ii) Exercise causes the heart rate to change. Explain what causes these changes. (4 marks)
(i) 1 Heart rate increases in anticipation of exercise;
2 Caused by release of adrenaline.
(ii) 1 During exercise – increasing release of carbon dioxide through aerobic energy supply;
2 Leads to increasing acidity (levels of CO2) in blood;
3 Detected by chemoreceptors;
4 In aorta/carotid artery/medulla;
5 Nerve impulses to (cardiac centre in) medulla;
6 Decreased parasympathetic stimulation;
7 Increased sympathetic stimulation;
8 Of SAN to increase HR.
(c) A 17-year-old runs 400 metres with maximum effort in 60 seconds. Describe the variations in
heart rate and how these changes are achieved during the:
(i)
(ii)
(iii)
rest period immediately prior to the start of the 400 metres.
The 400 metre race (exercise period)
five-minute recovery period after the 400 metres.
(i) Heart rate increases/anticipatory rise;
(Prior to exercise) adrenaline/noradrenaline released (by the sympathetic nervous system);
Parasympathetic (Vagus) system decrease in activity/impulses;
(ii) Heart rate rapidly/equiv increases
(During exercise) proprioceptors/mechanoreceptors/sense organs detect movement;
Production of carbon dioxide/increased blood acidity/lactic acid/pH falls;
Stimulates chemoreceptors (in aorta/carotid body/carotid artery);
Stimulates cardiac accelerator/medulla (in brain);
(Increased) sympathetic stimulations/release of noradrenaline/norepinephrine;
Sino Arterial Node (SAN) stimulated/excited;
(iii) Increased heart rate raises blood pressure;
Stimulates baroreceptors (in aorta/carotid body/carotid artery);
(Increases) Parasympathetic/ Vagus system;
Decreases Sympathetic stimulation;
Release of Acetylcholine;
Heart rate is high/maintained and then drops/decreases.
(3 marks)
(4 marks)
(3 marks)
Have these questions been answered?
• How does the heart rate respond to exercise?
• Does it respond differently to maximal and
submaximal exercise?
• How does the heart rate differ between the rest,
exercise and recovery phases of movement?