The Strider: I need to sort out my drink problem

At last, an easy fortnight. The week before last I kept the mileage up, with a speed session on the track thrown in (4 x 800 metres with 90-second rests, followed by 4 x 400m), and finished the week last Saturday with a steady 15 miles in Richmond Park (1hr 56min), clocking up a 42-mile total for the week.

At last, an easy fortnight. The week before last I kept the mileage up, with a speed session on the track thrown in (4 x 800 metres with 90-second rests, followed by 4 x 400m), and finished the week last Saturday with a steady 15 miles in Richmond Park (1hr 56min), clocking up a 42-mile total for the week.

This last week has been an easy one, comprising a track session (6 x 400m), an eight-mile run and an easy jog. The reason for easing off is because today I am running the Reading Half-Marathon, which will be a significant test of my fitness – a measure of how effective the training has been so far, and also a guide to judge if I am on course for my intended London Marathon time of three-and-a-half hours on 14 April.

The half-marathon distance of 13.1 miles, and the time taken to cover it, a shade over 90 minutes, is just within the limits of the body's store of easily useable energy. Any further, in a race or training, and you'll need an isotonic drink (no, not gin and isotonic, as one writer recently observed).

These replenish carbohydrate stores before the body starts to look for an alternative energy source to protect the reserve of blood sugar on which the brain relies.

Isotonic drinks provide this energy in a dilution equal to the body's, which makes them fast to absorb, and, being a liquid, they sit lightly in the stomach.

The problem is that these drinks are bulky and difficult to carry, although a concentrated version has been produced in the form of a gel. But it needs to be taken with water, which one has to carry, thus defeating the object of running light. And if you don't take it with water, gel can cause dehydration and cramps.

But this advance in energy technology comes in the form of an unpalatable slime. In an attempt to make the gels tastier, manufacturers have developed various flavours, which provide a thin disguise. Banana is not too bad – the consistency is actually like an overripe banana. Vanilla is surprisingly good, too. However, because I do not like the isotonic drink which will be given out during the London Marathon I will have to carry a gel. How I will do this is not yet clear.

I find wearing a belt with a pocket uncomfortable. I have tried winding a sweatband round my wrist and tucking the sachets of gel under it, but that was uncomfortable, too.

Somehow I have to find a way to fasten them to my body or clothing, in a manner that makes it easy to pluck them off. Velcro?

Entries are now closed for this year's London Marathon. Visit www.london-marathon.co.uk for all the latest news and details of the entry system for next year

The Strider returns on 24 March