Sometimes it is fast,

Sometimes it is slow.

Sometimes it does ponder

Whether it should stop or go.

It can make us happy,

And it can make us sad.

It can make us worry,

And it can make us mad.

It can be heard,

It can be felt,

It can be seen,

It can be spelt.

It can tell us a lot

Or it can tell us a little.

It always tells us

That our lives are brittle.

A feeling, a sound,

Controlled by our breath,

Can be the difference

Between life and death.

Though it may be soft,

Barely heard,

In context, heartbeat

Is a very strong word.