Hello,

For the last month I've been waking sevral times a night.  The first inspiration after waking sets off a vibration in my chest. The frequency is about 100hz and it's very regular.  It's not my heart - that beats at the normal frequency.  I've had all the appropriate heart tests and everything is clear, including an ECG whilst the chest is vibrating.

It's getting stronger and the frequent wakings are annoying.  I have felt around the chest and can't identify the muscles that are causing this.  What muslces are involved?  Intercostals?  Also, is there something I can or should be doing with these vibes?  What do they mean? 

Thanks for the advice.

edited--

I meant 10hz.

Having read a few things on the net, I can see how common this is.  And to me that means it's probably nothing of any importance.  The following seems like the most likely and least sexy explanation.

http://www.meditationexpert.com/yoga-kung-fu/y_vibrations_caused_by_yoga_meditation_techniques_are_chi_channels_opening.htm