It seems to govern so much of our lives. It starts as a child with birthdays, balloons and excitement, before increasing in pace as teenagerhood, careers and the pressure of family life add their demands. Finally there's the senior years which seem to bring to a crescendo the "tick tock" of the body clock.
Are we really just helpless victims? Or is there any way we can take back some control?
These questions came to mind as I contemplated a couple of items in the news.
First was Apple and Facebook with their offer to female employees to fund the freezing of their eggs so they could put off starting a family - an idea which has aroused some concern.
'There's no guarantee that an egg freezing procedure will extend a woman's fertility, and the American Society of Reproductive Medicine advises against relying on it, citing, among other things, the "potential emotional risks" and "false hopes" it can create,' reportedInc. magazine's Jill Krasny.
Second, the problem of jet lag has just got an upgrade. It no longer simply threatens sleepless nights and disrupted days. According to investigators there's a long term impact from frequently disrupting our "biological clock" in this way, namely "a tendency to develop obesity and other metabolic complications".
In both cases, the message seems loud and clear: "Don't mess with your body clock!"
But does our physiology always have to be at the beck and call of time? What if we could quieten the ticking of our body clocks through gaining a more spiritual sense of ourselves?
That's what has worked for me while criss-crossing time zones for the past 25 years. Or, as I gratefully confided to a neighbouring passenger on a recent trans-Atlantic trip: "I don't do jet lag!"
At the time I was on the first of three flights which took me from America's West Coast to an important meeting in the UK, 24 hours later. Despite having virtually no sleep I remained fully alert throughout the meeting and simply went to bed at my usual time later that night.
How did that happen?
I can't deny that waves of tiredness swept over me as I flew into Heathrow on the overnight flight. Yet instead of just giving in to it, I took a mental stand against "the tyranny of time", as so many have rightfully described it.
To put it another way, I perceived that my ability to be where I needed to be, and do what I needed to do, was based on spiritual rather than material factors. And for me the key factor was understanding where my energy and alertness actually came from. I'd learned the source of such qualities isn't the time-sensitive human mind and body. Instead, it is the divine Mind which is not subject to time because as Spirit it can't be aware of any material measurements. The divine Mind is conscious only of its own eternal nature.
This was not so much an "aha" moment for me as it was an affirmation of something I'd glimpsed two decades before, after several years of suffering from jet lag. I questioned the belief I needed to pay a penalty for crossing time zones by grasping something of the idea that we "...own no past, no future, we possess only now" (Mary Baker Eddy, Miscellaneous Writings 1883-1896).
This gave me a sense of how the Divine influences mind and body each and every moment, allowing me to successfully challenge the seeming inevitability of being governed by the 'tick tock' of a biological clock.
But could a similar prayerful approach also help during the much more serious challenge of the potential complications of a pregnancy in later life?
One woman reported the following experience as she prayed for another woman, considered too old to safely have children.
"The doctor had predicted that the pregnancy and birth would be difficult and that she'd need a Caesarean section," said Christian Science practitioner Alessandra Colombini. However, as they prayed together during the pregnancy, the mother was healed of anaemia, circulation problems, and other complications and remained "confident and not afraid".
In the hospital, even though the baby was found to be in a breech position it became clear there was no need for an operation.
"The woman was rushed to the delivery room, where the baby was born normally and quickly," Colombini recalled.
There's an understandable logic to the assumption life is steadily ticking away, but in every case where prayer successfully defies that belief it raises a profound question.
Are we sure we're beholden to the ultimate conclusion of that conviction - namely that "none of us gets out of here alive", as the saying goes?
Or could the death and resurrection of a Galilean carpenter called Jesus have set the clock ticking on that very assumption 2,000 years ago?