Training & Nutrition - HRM Interference

I've had my Polar HRM for a few montha and it has worked flawlessly. Today I went on my first area club ride of the season. I wore the same clothing that I have been wearing on other rides. Nothing different.

I get a quarter mile into the ride and look at the HRM and WOW I'm at 225. I know this is not right. The thing ran very erratic for the first 9 miles. I finally stopped it and then restarted again. Finally things seems to start working better, more in line with what I've been seeing before on rides.

So my question is...what may have happened? My only thought is that the day before I readjusted my wireless Cateye sensor on my fork. It's probably about an inch higher that it was before. I have both the Cateye and HRM attached to the top of the handle bar one on each side of the stem.

I've read about shirts causing problems, power lines, and other riders. I really don't feel any of these are the problem in this case. I had a cotton shirt on underneath the jersey I was wearing, no power lines during a portion when the HR was showing way high and no other riders close, except for my riding partner who has ridden with me this year and I had no problems.

Any ideas? Kinda bummed my out as I have really grown to like loking over the HR results after a ride.

Sometimes, if you're riding close to other people, the polar will pick up other polar wearer's signals. Deosn't matter if you strategically place your strap or monitor under clothes- it just happens. Power lines have been known to affect readings too, and you don't need to be right underneath one in order for it to mess with you. Your watch may be messed up, but doesn't necessarily mean everyone else's will either. Sometimes, it just happens.

:( Welcome to the world of polar.

Koffee

Well I'll have to see how things go the next time I'm out riding. I'm also going to try to find out the wireless frequencies used by each device. Maybe lower the Cateye sensor lower on the fork like it was before. We'll see.

Maybe your right..."Sometimes it just happens".

Sometimes, if you're riding close to other people, the polar will pick up other polar wearer's signals.

That is exactly what happens when my Sigma PC1600 HRM displays a 'beyond-death' HR. My riding buddies use the same HRM and interference is normal.

But Polar, if I am not mistaking, boasts something like 'encoded frequency' (forgot the accurate terminology), which implies that their HRMs are tuned to pick up only the signal from the wearer's HR-strap. If this is the case, you could expect interference to be irrelevant, couldn't you?

Any chance the transmitter strap was a little loose, or had gotten dry prior to taking off? My manual lists a boatload of things that will cause interference, and also says that you shouldn't start measuring in proximity to others w/HRMs. I guess if it's encoded, it might get confused about which transmitter to lock to???

When you restarted it, you probably were sweating (i.e. better contact) and further away from other HRMs.

I suppose it could have gotten dry. The thing is that when I got on my bike right at the start all was well, quarter mile down the road and I was at 225. In reading the manual tonight I think I may have one possibilty I hadn't thought of. Electric cattle fences. The ride was in a small town (Union, IL) and there were quite a few farms. I remember seeing some cattle, and smelling them! When I was reading the manual the light went off when I saw the comment about electric fences.

I went for a run tonight and everything was cool with the HRM. Also I am ruling out other riders as there was no one around me when I started out and things went haywire.

Figured it out today. Got on the bike for a ride (beautiful day here) and the HRM went wacky right away. Went back to the house and lowered the wireless Cateye sensor on the fork.

Now everything is fine. I guess a few inches made a difference. Still seems kinda weird...but everything was OK when I got back on the bike.