One heath. Four seasons.

Last night I imbibed a fair amount of Christmas cheer, so I was proud I even made it to the start line for today's parkrun.

There would be no striving for a PB, I'd decided a gentle potter was on the cards.

An approach that was further endorsed when I arrived to find Hampstead Heath under a thin layer of ice. It was treacherous.

In fact, I nearly ended up on my arse during the pre-race briefing.

I was listening attentively when I received a firm shove in the rear. I wondered briefly if it was the man I'd pipped to the post on my last outing, but thankfully not. It was just a very excited dog. And, after a bit of wrestling, his apologetic owner managed to separate us just in time for the start of the race.

I'd resolved to take it easy - and I did. On such a gorgeous morning, it was comparable to taking a leisurely sightseeing tour. Even running uphill was a pleasure. And when I got to the finish, I was red faced, but human.

Time for fitness part two - off to the ladies' pond.

It was freezing. Fricking freezing. In the time it took me to put my cozzie on, the weather had turned from cold but bright to sodding cold and sleeting grey. Walking from the changing room to the water took less than 30 seconds and yet I nearly changed my mind. Twice. In the end, I think I was only in there for about a minute. Every single bit of my body hurt. I swam out to a buoy, then as fast as I could back to the ladder; all the while reciting the calming yogic chant: 'f**k, f**k, f**k'.

Once I'd regained my senses, I spotted a funny machine by the entry platform. It seemed to be churning the water. I spoke to a lady and she said it was used to stop the pond from icing over. In the past, they would just break the ice with a broom, but understandably that didn't leave much room for laps. Fascinating stuff, but I couldn't help thinking it was a great shame it didn't heat the pond too.

(Stats: 5k/3.10 miles; 28.39 minutes; 9.13 minute/mile. Pond temp: 4.5 degrees celsius/40 degrees fahrenheit. Cold enough that an hour on and my woolly hat is still glued to my head. And that's despite being at home under a blanket.)

(Pic: Lovely light on the heath this morning - pre-sleet.)