I am 84 years old and have two worn knees. The GP and physiotherapist both tell me to keep moving. But if something is worn out, you have to be careful with it, right?
With a worn-out machine, you can save time until it breaks by putting as little stress as possible on it. But worn knees remain living tissue. They need oxygen and nutrients – and they get them through exercise.
Cartilage
The inner lining of our joints consists of cartilage. Cartilage does not have its own blood vessels. The supply of oxygen and nutrients goes through the synovial fluid that surrounds it. The cartilage acts like a sponge: if you put a load on it (for example by standing on your leg), it is emptied. If the pressure then drops because you lift your leg, it will suck itself full of fresh joint fluid.
Movement necessary
Keeping moving is therefore necessary to keep the joints healthy. This is even more important when the joints are already weaker. The ‘wear’ mainly consists of deformation due to years of damage and repair. People who do heavy physical work are more likely to develop osteoarthritis (or wear and tear), but this is mainly because they put an unnatural load on their joints, for example by sitting on their knees for a long time or working with vibrating machines. Walking and cycling are excellent forms of exercise and exercise. It is better to avoid large peak loads and prolonged sitting in the same position.
