My husband adores gadgets so when my cardiac physiotherapist suggested I buy a heart rate monitor to use when exercising he got very excited.

"I know just the one," he said, hunting through our pile of House and Garden magazines for an issue of Men's Fitness.

He flicked through the pages until he found an advert for a spectacular device with a multitude of features that would help me reach Olympic standards.

"I don't want one as flash as that," I said.

"But you can wear it as a watch, too," he pointed out. "It's super cool."

"It's not," I said. "It's big, grey and ugly. And I'm never likely to need something that compares my performance with Paula Radcliffe's. I'll just get a simple one - preferably in lilac."

I haven't yet found the one of my choice, but I returned to my gym this week for the first time in ten months and started doing the regimen of exercise as prescribed by my physiotherapist.

As a heart failure patient, I'm being encouraged to exercise as increasing your fitness levels diminishes the typical symptoms of tiredness and breathlessness.

I actually don't have any symptoms caused by my condition. My fatigue is purely family related.

I know this because I did an exercise test at the hospital for them to work out the amount of oxygen I use when exercising at full capacity and I scored the average for someone ten years younger than me (so from now on, I have a legitimate reason to pretend I'm only 30).

In fact, the physiotherapist reckons that before I had heart failure, I probably had it in me to be a world-class athlete. If only I'd known!

Even though I'm not doing too badly, there is still room for improvement. So now I'm on four sessions a week working at a heart rate of between 120 and 130 beats a minute.

For my first trip to the gym I borrowed a heart rate monitor and began pedalling away. After four minutes, my heart rate was up to 128. It then started to decline dramatically - 95 ... 79 ... 50 ... 35 ..... zero! It was a bit alarming. I stopped and put my hand on my chest. My heart was still beating, but the monitor's strap had slipped down to my belly and was picking up gurgles instead.

I adjusted it and resumed pedalling. Six minutes .... seven minutes .... it was taking an awfully long time to reach my 20-minute goal and the electronic display of my workout looked very dull. But If I went above level 2 my pulse shot up to 143.

Meanwhile, the girl on the bike next to me was doing hill training and was sweating like a mule. How I envied her.

Still, half an hour later, having completed the proper cool-down and stretching, I felt ready for anything while the sweaty girl crawled her way back to the changing room.

She was probably going to spend a quiet evening in front of the telly with a takeaway to replace the body fat she had just lost.

I was going home to the physically demanding task of getting two small children fed, bathed and into bed.

"I know what extra features I want on a heart rate monitor," I said to my husband later. "One that also reminds me to turn off the grill and sings lullabies."