• Question: Why do we get tired after we run or do something very fast?

    Asked by Sammy to Hayley, Jimi on 18 Mar 2016.
    • Photo: Hayley Moulding

      Hayley Moulding answered on 18 Mar 2016:

      Our muscles and our body’s are having to work really really hard really quickly. Sometimes lots of chemical build up in the muscle and lots of chemical reactions are taking place. We get tired as we have a thing called ‘sleep debt’ which increased when you do more activity. You are using up energy when you are running or doing something fast, so the body doesn’t have enough to keep all the reactions going as well, so it starts to slow down a bit and get tired.

    • Photo: Jimi Wills

      Jimi Wills answered on 18 Mar 2016:

      Muscles use up food and oxygen.
      There are reserves of food an oxygen in the muscles.
      There’s food an oxygen in the blood.

      But when the muscles use up a lot of food an oxygen, so much that there’s not much left in them or in the blood, then your body needs to get more…

      the lungs take oxygen from the air, but can only do it so quickly.
      the body releases food from stores around the body, but it can only do it so quickly.

      So if you go too quick the body can’t keep up with the needs of the muscles and you feel tired.

      Same goes for waste products generated by the muscles… but in the opposite direction