Exercise

							Exercise




           1
         How the body changes
                                                                          2



           during exercise
                                                       4.The lungs start
1. First, the muscles                                  breathing faster and
start to work harder                                   more deeply. They
                                                       remove CO2 faster and
2.This means more                                      take in oxygen faster
carbon dioxide                                         5. At the same time
forms. The level                                       the heart starts beating
rises in your blood                                    faster, pumping blood
                                                       faster around the body.
3. The brain detects
this rise. It sends                                    6.Since the heart and
signals to your heart                                  lungs are both working
and lungs to work                                      harder, more oxygen
faster                                                 reaches the muscles
                                                       each minute, and
                        7. This means the muscle can   more carbon dioxide is
                                                                          2
                        keep on working                carried away
Other Changes to the body
  Increased respiration in your muscles generate more
   heat. So your blood gets hotter
  To cool the blood down, more is shunted close to the
   skin. This makes you redden.
  You also sweat, which cools you by evaporation.




                                                          3
Heart rate
stroke volume




Respiratory rate
Tidal volume       All these increase
                   during exercise
Minute volume

                                        4
       Fit and less fit during
       exercise
       Two runners run the same course one is fitter than the other.
       You can tell by looking at their heart rate

               185
                                                        less fit
               170

                                                         fit

                82                                                  Runner A
                65                                                  Runner B



                     0     5       10      15     20           25
(i) Lower resting heart rate (ii) Lower heart rate throughout (iii) Quicker to   5
recover back to resting rate
Lactic acid removal
 Oxygen removes lactic acid from the body.
  This is called repaying the oxygen debt. The
  process is faster when you do a cool down
                   Active Cool
             100
                   down
   Lactic                        Resting recovery
   acid
   removal    50
   %



               0             1                 2
                        Time (hrs)
                                                    6
   Recovery after exercise
 Muscles may suffer minor damage during training.
  Your body has to repair this.
  Stiffness and soreness take time to clear.
 Stretching as part of a cool down helps prevent
  stiffness
 Glycogen stores need to be replaced
  It can take up to 48 hours for glycogen stores to
  recover



                                                      7
How long does recovery
take?
It depends on
 How strenuous the exercise is
 Your fitness. The fitter you are the faster you
  recover
 Allow 24-48 hrs between training sessions to
  recover
 If you train every day, follow a heavy session
  one day with a light session the next

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