When my father died, he left a stack of oral morphine by his bed, and my brothers, sisters and I all took it to see if we would get high. We didn’t. “Maybe it only works if you’re actually in pain,” I said. My sister replied: “I am in pain! My dad just died.” And we all laughed for a really long time, so maybe we were a little high.

I thought of this in the Cannabliss class, at Gymbox in London (it’s very new: your local leisure centre is unlikely to be experimenting yet). CBD is a non-psychoactive cannabinoid, found in cannabis, which has many of the plant’s beneficial qualities. Unlike tetrahydrocannabinol (THC), AKA the fun one, it doesn’t get you high. It’s beneficial for all kinds of complaints that I don’t have (epilepsy, Alzheimer’s). It can also be used for fitness purposes; it has anti-inflammatory qualities, and can allay muscle pain. You can get it in many forms: jelly sweets, topical rubs, tinctures, oils. There is even an aphrodisiac oil, but they didn’t send me that, maybe because I’m in my 40s.

In this class, it takes the form of a CBD patch, placed on your stomach before undertaking some deep and damn painful muscle-releasing exercises. I call them “exercises” – it was more like grinding into your muscle to find the uncomfortable bit, then doing that some more.

For instance, you might get a satsuma-sized, hard ball and roll the arch of your foot over it, again and again. The guy described it as like scraping barnacles off a ship, worrying away at the knots of tension.

The principle of the patch was that, the more relaxed you were, the better it worked. I knew that it wouldn’t make me high, but I nevertheless felt quite giggly. “Lift your leg, then next step,” he kept saying. That’s great, I thought. I wonder what the next step is? Ah. He’s saying “extend”. By now I was laughing out loud, and the woman next to me started to laugh. We were not stoned, I say that categorically, because I totally understand science; but somehow we’d persuaded ourselves that we were.

I cycled home feeling quite fly, and free. There is certainly something in it: you feel very loose afterwards, as if someone kind has taken a rucksack off you.

Back home, I tried the sweets and the oil, and tested them on other people. Again, the effects were so subtle it was impossible to tell whether they were really happening or just supplied by the expectations of your infinitely creative brain. One friend couldn’t stop eating cheese; another said trenchantly that it had made no difference. But both those responses dovetailed pretty well with their underlying personalities, so I don’t fancy this for a peer-reviewable study.

My advice? Start with some actual pain, in an actual muscle, rub some CBD oil on it, then work from there.

What I learned

Buy CBD products made in Colorado or California. (European and Chinese CBDs are cheaper, but not thought to be as good.)