Wow! Scary answers!

Since you hear it in certain positions on the pillow, I might suggest it may not be the death knell that Ed points to.

Perhaps it is simply that you have a rather large heart still, from having served your 113lb larger frame, and now with all the weight loss, the beating heart is transferring cleanly through your chest cavity to the bed springs, and when you lay certain ways with your ear on the pillow.

Obviously, I'm no Doctor, but by your description this seems plausible and you could test it by laying on a different surface to see if the amplitude changes (i.e. a foam mattress rather than spring).

Again, since you don't hear it flat on your back, I think several of Ed's scary possibilities may not be worth reviewing.

I have similar issues, strong pulse in abdomen and other places and sometimes can hear it when laying down. My BP is usually 110/70. I think (and my osteopath has agreed) that it is stress related. Unfortunately it is somewhat unnerving, creating a vicious cycle, the more you worry about it, the more you notice it.

I'm no doctor either but this was my experience with what may have been a similar problem:

Are you eating a very low sodium diet? Your problem sounds similar to a problem I had. I have eaten a very low carb paleo type diet for a number of years. A couple of years ago I started eating a very low sodium diet too, mostly because I ate everything fresh and cooked/baked all my own food and used a potassium salt substitute for seasoning. Over a period of time, problems with hearing and feeling my heart beat increased until it was difficult for me to sleep at night. I would have to get up and sleep in a chair. I thought I remembered reading in another low carb forum a post from a woman who mentioned that she started to have episodes of hearing her heart beats. She said -if I recall correctly - that she dipped her finger in some salt and licked it and the salt seemed to help. I would get up and do that and it did allow me to get some sleep. However, what really helped stop the heart sensations issue with me was to actually add some real salt to my diet. I started eating some sauerkraut, olives, and pickles and the problem, for me, stopped almost immediately and has not returned. I was interested to see that the Drs Eades mentioned "Keeping up your salt intake." on page 144 of their new book -The 6 Weeks Cure for the Middle-Aged Middle.

I need to preface my remarks by saying that what I'm telling you is general information and not medical advice. The phenomenon of hearing your own pulse is called "pulsatile tinnitus" and can have a variety of causes, some of them serious (see http://yourtotalhealth.ivillage.com/sound-pulse-in-ears.html ). Even if overall blood pressure is normal, the pulse pressure, or systolic BP minus diastolic BP, may be elevated (greater than 50mm Hg) in some cases. Elevated pulse pressure can be caused by anemia, pregnancy, hyperthyroidism, arterio-venous malformation (AVM), heart valve leaks, and brain tumors. Most of these conditions, with the possible exceptions of anemia and hyperthyroidism due to iodine over-supplementation, would not be caused by a paleo lifestyle. Whether or not your pulse pressure is normal, please consult your personal doctor or an ENT specialist regarding your condition.

Ow god, that answer sounds scary man..

I spoke to some people who are on paleo, and never have i heard your question. I suggest (just as the scary answer :P) that u check out your doctor. Just dont worry about it too much. It could be nothing.

Have had similar problem (feel pulse strongly in abdomen/other places). I never investigated but it went away. I considered stress, a very low-carb diet (at the time), and various supplements I was taking. I worried a little at the time about pulse pressure but since it went away, I forgot about it. If you do go to a doctor and find anything out, let us know. Best, Jay

I also have a similar issue with hearing my heartbeat. I'm also an acupuncturist. I would recommend trying out acupuncture because this phenomenon is often stress related and can easily be treated.

I have heard my heart beat every night from when I was a kid up to now. I have found that setting a fan speed to low in the room while I sleep really does help.

It could be hyperthyroid. I was once hyperthyroid and I had that happen. Another possibility is you prefer to lay on your left side. If you do, the heart has to work a bit harder and can sound noisier. Or so I read recently. It is true, I don't hear my heart beat when I lay on my right side or my back.

I have exactly this same issue on low carb. Been this way for around 2 months.

I get both a much stronger more noticable pulse, especially at night. I also get hypnogogic jerks (feeling of falling as I go to sleep, and having a startle). Feels like I am a bit more wired, and my heart is going harder. It seems to be consistant, but is worsened by stress. It gives me trouble getting to sleep. Once I am there, no problem.

I have been to a doctor. They listened to my heart, and said it was normal. Got sodium and potassium levels checked, both normal. I am going today, to see them again, see if I can get this worked out, without some casual dismissal.

It feels like either I am somehow more adrenal, or my heart is overcharged a little somehow. Heard some people get more energised from coconut oil, so think I may ditch that for awhile.

This seems like a rather common issue, I have heard of people have hypnogogic jerks, getting anxiety, higher blood pressure, trouble sleeping and faster heart rates on low carb. Sometimes that may be related to electrolytes. In my case, at least with that I am currently eating and drinking, I dont think thats so.

I am a little concerned, because I am low carb for my illness, not out of mere choice. Hopefully I can either supplement my way out of it, or figure it out somehow (or adapt perhaps)

Gee, I didn't know whether to make this a comment or an answer. I had this problem too but never knew it had a name. Anyway, I just realized that this is no longer a problem (can't hear it anymore). I really have no idea if it's because of diet or exercise or whatever. My BP has always been low. It may have started due to some mild trauma but I don't know. It was only really noticible when I was laying quietly. If there was ambient noise then it was less bothersome. If you are really concerned and think there might be a deeper problem going on then get it checked out! Otherwise, having some other humming-type sound around may distract you enough that it won't annoy you.

I had an ear infection many years ago (pre-paleo)

I could hear my own heartbeat then...

When I cleared that up, the sound went as well.

I would agree with your pointer to this medical problem if she heard the noises all the time or upon exertion. Since it is only heard at rest and in certain sleeping positions, I would strongly doubt that it is pulsatile tinnitus.

I suspect that you are compressing your ear's superstructure slightly when you sleep on your side, and that compression is giving you a sort-of better hearing via conduction from the labyrinthine artery of the inner ear.

http://en.wikipedia.org/wiki/Labyrinthine_artery

If this was happening to me, I would not worry about it.

I see this was asked months ago, but maybe it can use a little elucidation anyway. If your heart is beating strongly, you can sometimes hear the pulse in one or both ears, or see/feel it in the abdomen when laying flat (or feel it in the chest when laying on your left side and compressing that region).

But if your arteries are elastic, as they should be, then they will give way to the pressure and your blood pressure will not necessarily be high. In fact, if you were to deliberately dilate arteries, then the heart must beat faster (reflex tachycardia) and/or stronger to make sure enough blood is being supplied.

Or it could be from local swelling as Stephen-Aegis said.