There’s a strange thing that can happen at the end of a long day.
You haven’t run a marathon.
You haven’t spent eight hours digging a trench.
Yet the idea of going for a walk, doing a bit in the garden or even tackling one more job can feel like somebody has added weight to it.
You look at it and think...
Not tonight.
I’m done.
I’ve noticed something similar at work.
On some afternoons, the first sign that I was running out of steam wasn’t physical.
It was my concentration.
I’d become easier to distract.
Things that normally held my attention took more effort.
Then later came the lethargy — and occasionally the feeling that I’d simply had enough and wanted to pack up and go home.
For a long time I bundled all of that together under one word:
Tired.
But there’s an interesting bit of research that suggests there may be more going on than simply having an empty physical tank.
Researchers at Bangor University once put 16 people through two different sessions.
In one, they spent 90 minutes doing a demanding mental task.
In the other, they spent the same amount of time watching fairly neutral documentaries.
Then they got on exercise bikes and cycled at a hard, fixed intensity for as long as they could.
After the mentally demanding session, they gave up sooner.
You might assume their bodies had somehow become more physically exhausted.
But that wasn’t what the researchers found.
The usual physiological responses to the exercise were largely similar.
The big difference was this:
The exercise felt harder.
That’s the bit I find interesting.
Their legs hadn’t necessarily been secretly emptied by thinking.
But after a long spell of mental effort, the same physical work seemed to cost more.
Now...
This was a small laboratory study.
Sixteen people on exercise bikes is not the same thing as you finishing a day at work and deciding whether to walk the dog.
And research in this area doesn’t show that mental fatigue affects every person, every activity or every day in exactly the same way.
But it does give us a useful possibility to consider.
Sometimes when you think...
“I’ve got nothing left physically.”
...what you’re feeling may partly be:
“Everything feels harder than it normally does right now.”
Those are not quite the same thing.
And I think that distinction matters after 50.
Because if every difficult evening gets interpreted as proof that your physical capacity is disappearing, it’s very easy for life to start shrinking.
The walk gets skipped.
The garden waits.
You stop suggesting going somewhere after work because you assume you won’t have the energy.
Not because you definitely couldn’t do it...
But because the thought of doing it feels expensive.
So here’s something worth noticing this week.
Think about the days when physical activity feels unusually unappealing.
What happened before that?
Was it actually a very physical day?
Or was it one of those days full of decisions, problems, concentration, interruptions and things constantly demanding your attention?
Then compare it with an easier day mentally.
Does the same walk, set of stairs or job around the house feel different?
You’re not trying to diagnose yourself.
And I’m certainly not suggesting you should ignore genuine physical exhaustion and force yourself through it.
The experiment is simply to stop treating the feeling of effort as a perfect fuel gauge.
Because it may not be one.
Sometimes the body genuinely needs recovery.
Sometimes something medical needs investigating.
And persistent or worsening fatigue that is affecting normal life deserves a conversation with your GP rather than being explained away as “mental fatigue”.
But on an ordinary long day, there might be another question worth asking before you write the evening off:
Am I physically empty...
...or does everything just feel harder right now?
Those two things can feel remarkably similar.
But they may not always mean the same thing.
Speak to you Friday
Nigel