I have never had much trouble getting to sleep. Quite the opposite in fact.

Of all the ailments I've imagined during a lifelong dedication to hypochondria, insomnia is one I've never been able to add to my list of fears.

However of late I've had some trouble staying asleep, and this is offering extra mileage for anxiety.

In the past I could sleep through TV theme music, thunder, lightning or any storm with a Christian name. What's gone wrong?

Being unable to stay asleep and then losing sleep through worrying about it is one of modern life's familiar vicious circles.

In my case I'm hoping it's not a symptom of anything more serious than too-thin curtains, letting in the 5am sunlight.

And now that the summer solstice has been and gone and the days are shortening by around 15 minutes per week, the problem may lessen as time goes by.

However earlier this week I was woken in the early hours not by intruding sunlight but by a strange ringing in my ears, or perhaps more of a humming.

At first I thought it was the soundtrack of a dream I hadn't quite shaken out of my head.

I was still half-asleep as I stumbled towards the bathroom, and though the hum seemed to be getting louder I still believed I was half-dreaming.

A few hours later I woke again, beginning to worry. The hum was still there. Could it waken the next-door neighbours? Was it a fault with the electrics, the shower, the plumbing? Was a section of ceiling about to come crashing down?

When I surfaced again at 8am I discovered its source. For some reason I'd left my electric toothbrush on.

If only all anxieties, all the noises in our heads, had such easy explanations, and could be solved at the push of a button. Because we've all got worries.

Of course some are far more troubling than others. People with a serious illness, who fear for their jobs or can't pay the rent or mortgage are more entitled to anxiety than someone who's spilt tomato sauce on their shirt and worries whether it will come out in the wash.

Even those without obvious focuses for anxiety will worry about their health and wealth, their work, their relationships, the welfare of their children or ageing relatives, or the return of the floods that have become regular visitors to Cumbria.

And the only people who aren't worried about climate change are the ones who haven't looked at the facts.

Yet we all have different capacities for worry. Some people get more anxious than others. And of course it can be crippling for them.

But being a worrier is not necessarily a bad thing. The wartime song Pack Up Your Troubles gets it wrong when it says: "What's the use of worrying? It never was worthwhile."

Nor can I accept Bob Marley's advice: "Don't worry about a thing. 'Cause every little thing's gonna be alright." Who says it is?

There are many possible benefits to anxiety. If you don't worry about getting cancer or being involved in a car crash, then you won't take the steps that could prevent them.

But if worrying leads you to give up the cigarettes, lose weight, check your brakes are working and stick to the speed limit, then of course it's valuable.

Some people worry abut what others think of them, and there are times when that too can be beneficial.

If you're anxious to be liked or to make a good impression, then you'll be more careful not to offend someone or hurt their feelings. That can only add to the general sum of human happiness.

There's some evidence that people prone to worry have better memories - and so sometimes fare better in exams.

And psychologists argue that they can be better decision-makers. If you have a tendency to think through everything that could go wrong, your final decision could be a safer, more carefully considered one.

What's nice about worrying, though, is how pleasantly surprised you are when difficult jobs prove easier than you worried that they might be, or when things in general turn out alright.

If your mobile phone isn't working and you're a worrier, then you might fear that it's broken. Discovering that it's only that the battery is flat can bring a great sense of relief.

That feeling of relief is often gratifying enough to make the initial worry seem well worthwhile.