Q. Why do we keep breathing when we're asleep?
A. Our breathing is regulated by the autonomic or 'automatic' nervous system over which we have no voluntary control. Breathing is controlled by the part of the brain called the medulla oblongata or brain stem.
Q. How long can a whale hold its breath?
A. The longest that a bottlenose whale can hold its breath is nearly two hours.
Q. It seems like 100-metre sprinters and swimmers hardly take a breath for the whole of the race. Is this true?
A. Yes. Many 100 metre sprinters do not breathe at all during the race. They can take in all the oxygen they need before the start. Swimmers may need to take the occasional breath as their races last longer.
Q. Why do people yawn?
A. Sometimes we yawn because there is a need for oxygen on waking or if fatigued. The cause of yawning is unknown at other times.