Did you know tensing certain muscles while you give blood can greatly reduce your risk of fainting?
Fainting is caused by a sudden drop in blood pressure, but by doing muscle-tensing exercises you can actually help your body maintain pressure.
The exercises themselves are simple:
- Lie down on the donation bed.
- Cross your right calf over your left calf.
- Squeeze your thighs together.
- Tense your stomach.
- Point your toes back towards you.
- Hold this position for five seconds.
- Then relax for five seconds.
- Repeat this process five times.
- Now, cross your left calf over your right calf and repeat.
When you do these exercises (especially the ones with your calf and thigh muscles) the muscles squeeze blood out of the veins in your legs back to your heart.
Apparently, this is even used by air force pilots to prevent them fainting during G-force!