greenmande wrote:ive read comments saying that you can use a lotion to create the contact the chest strap needs...
can anybody confirm this?
I've used EEG's and EKG's a lot, on others and myself. In fact, you could say I was an expert, inasmuch as I knew a lot more about heart monitors than almost all the cardiologists I sold multi-million dollar HP heart monitoring systems to.
And, I've used those devices (can't remember their name) that generate STRONG electronic pulses into muscles using EXACTLY the same electrodes as the EKG and EEG electrodes.
The electrodes for both attach to the skin with peal-and-stick patches, and neither were functional at all without moisture at the point of contact between skin and electrode.
What's more, when in a pinch, or just curious, I have tried many various liquids besides the conductive gels specifically designed for such use. Some lotions and other liquids work a little, but none worked well (i.e. any where near as good as the real stuff), and most don't work at all.
For example, saliva (and water, until it washes away too much of the skin's surface salts, and/or until it evaporates, neither of which takes long) worked a little, but it didn't offer much more signal than the absolute minimum in order to distinguish the signal from the background noise, namely, by definition, a signal must be at least 2 times greater than the noise level in order to be considered a usable measurement, and not just noise.
KY surgical jelly didn't work at all for some reason, unless I added A LOT of table salt. And even then, it hardly worked at all? In fact, it actually behaved as a GOOD insulator would, to the point that it actually seemed to immediately inhibit or stop any conduction/readings that had been going on before adding any KY. Even when I added 5-10 times as much salt as would be needed to make water somewhat conductive, the KY would still hardly conduct at all.
Altho rare, a few lotions I tried had a tad of this type "current stifling" ability, as well. So, if you had one of those, it is very possible that it could stop readings from this...or at least, inhibit the natural conductivity your sweat would have without a lotion like this present.
With the KY, I always figured that they MUST add a heavy dielectric (non-conducting) agent to it for some reason...something beneficial to some aspect of certain surgical procedures, but this is only a guess? It's funny, tho, especially when you consider that electrode gel looks, feels, and even smells EXACTLY like KY...it even tastes like it (I know that because a woman I "knew" for a while in college was religious about keeping a tube in her night stand;-)
To answer your question, tho...it most probably depends on the brand of lotion, i.e., whether it has a sufficient concentration of salts and minerals needed to conduct a minimum signal strength. Like I say, lotions vary heavily in this regard., some having little to NO conductive abilities (some actually seeming to suppress conductivity), and some worked a little.
So, "the answer is:"
Get the monitor, and try some lotions. Some of the ppl here said, and I tend to give them the benefit of the doubt (even tho it is safer when online, at least, to assume everyone is lying ALWAYS), that they HAVE used it quite successfully with the brand of lotions they tried on it.
Again, tho, if you have trouble in this regard, you can get a life-time supply of genuine medical/research-grade electrode gel, i.e., a 20-40 oz. tube, for about $10-15.
