Tick tock

A quick one for the group theme this week of 'What makes you tick'. 
Having had a 'bit of trouble' a couple of years ago with the old ticker, this is one of the medications I take that regulates heart rate from going too high, so literally does play a part in making me tick.

It was described as like a rev limiter on an engine, so I imagine if I tried to break the 4 minute mile it would just hold me back. I'm sure I'd ace it otherwise!

p.s. I'm doing fine, so please, nobody worry :-)