SOMETIMES fitness is a pain - both metaphorically and literally.

As you know, I am a devotee of my July Jogging regime - running, or other substantial exercise, every day of this month.

Overall it has gone well, and between treadmill, pavement, pool, karate dojo (training hall) and garden, I have done something vigorous every day.

Half-way through, I can see the benefits. Muscle tone is better, weight continues to fall, mental alertness higher.

And I am enjoying the various activities, which is the best guarantee of continuation.

However, nothing is ever perfect, and as anticipated, constant exercise takes its toll.

Running on consecutive days is sore on the ankles and hips, and sweating daily can leave skin irritated - not much fun when you work in a warm back office with no fresh air. And the hassle of having to set aside training time every day for it is a nuisance.

One downside of such exercise is that it highlights the fact that I am no longer young.

Like most humans, I have a kind of innate belief that I will live for ever. Objectively I know the day will come when I am no more, but seem to have an internal denial mechanism which does not allow me to see beyond the health, fitness and intelligence enjoyed for 55 years.

I deal with other people's deaths - making wills, winding up estates, claiming compensation for bereaved families. My own death though seems a ridiculous, impossible nonsense.

Exercise is a double-edged sword. It promotes wellness, yet also reminds me of my growing limitations.

I can chart the decline of my powers over time, so my physical age is brought much more sharply into focus in training.

For example, I run more slowly now. In the 1980s my best marathon time was 3 hours 58 minutes.

I was in my 20s and, though not a natural distance runner, was accustomed to sport.

In May 2014 it took me nearly six hours, though I was injured and should not have been running at all. Fit, it would have taken me five hours.

Even so, that's a loss of a quarter of my speed. Both my daughter and son are keen sports participants.

Jonathan, 25, did a half-marathon in London in June, in 1 hour 36 minutes.

Hannah, 21, also a marathon runner and all-round sportswoman, is working as a sports coach over the summer, playing and teaching hockey and tennis every day.

I cannot compare to them, and the more training I do, the more obvious it is that I am a middle-aged overweight man heading to old age.

I get tired more easily and profoundly, while recovery of aching limbs takes longer than before. But again on the plus side, I thankfully still seem to have the heart and lungs of a bull.

Looking around at contemporaries is instructive. Some like me are regular participants. Through social media, I know who is doing what races, times, enjoyment or otherwise, and feed in my own data and results to the mix.

Indeed each week I place a link to this column in Facebook and on my own law firm's website.

BUT as well as the athletic (and try-hards like me - I would not dare call myself an athlete), there are sadly the give-ups, the have-a-beers and the couldn't-care-lesses.

And everything in between.

Some men and women of my age have hardly changed over the years, some look awful or ancient.

And while your face may be your fortune, it is also your calendar. It is easy to make a judgment of someone by their face - skin tone, bags, lines, jowls.

Smokers can betray their habit in pallid skin, nicotine stains and mouth lines. Drinkers show broken blood vessels, swollen features and flushed skin.

But brightness of eye is crucial. If you have it, based on healthy living, you have a priceless treasure.

Ageing is inevitable, but you can do it in style or with a whimper - that's where free will comes in.

They say that politics is the art of the possible. Health and fitness are just the same.

For any number of good reasons middle-aged folk may not be able to do sport or formal exercise. But we all have a best we can achieve.

This week I am more philosophical than usual. It's not all good, and the lines and aches are real enough - but all the more reason to train and compete.