The 'Valsalva manoeuvre'
Have you ever strained to lift or push an object and found yourself tensing up your whole body and holding your breath?
This is called the 'Valsalva manoeuvre' - where the breathing muscles tense up as if trying to breath out, but the mouth and throat are closed off so that no air can come out.
We do this instinctively, but it may be harmful to health, particularly if you have a heart condition. This is because it causes sudden changes in heart rate and blood pressure. It can also cause dizziness or fainting, since it reduces blood flow to the brain.
NEVER LIFT HEAVY OBJECTS