It's not always increased awareness that makes you realize that your heart is beating pretty fast as you lie in bed to go to sleep at night.

Though for some people, this explanation holds.

"It may be an increased awareness of your body's function (you are just lying there focusing on yourself without distractions)," says Susan L. Besser, MD, with Mercy Medical Center, Baltimore, and Diplomate American Board of Obesity Medicine and board certified by the American Board of Family Medicine.

Dr. Besser continues, "Two, because you are just lying there you may start to think about your day (and the stresses). Obviously that my raise your pulse.

"Lastly, when you lay down your blood pressure and other bodily functions adjust to your new position — that could also cause a transient increase in pulse."

If you know for a fact that your heart beats faster after lying down at bedtime – because you've taken or felt your pulse while awake at night and then taken or felt it again after getting in bed – this is clearly not an issue of increased awareness.

Keep in mind that simply taking or feeling your pulse while in bed can induce anxiety that makes your heart beat faster.

You may want to wear a pulse oximeter that records heart rate while you're up and about for a few hours before bedtime, and then keep it on your finger after getting in bed and falling asleep.

Next time you awaken, remove it. It will have retained a recording of the data.

The only caveat is that sometimes these devices are tricky as far as retrieving the data.

But if you can figure it out, you'll note that once you fall asleep, your heart rate will be slower than it is at any point of the day.

You'll also be able to see if your heart rate truly does soar after you lie down.

Note the time you get into bed, because the oximeter data will have a timeline to match that up against.

Shifting around in bed, struggling to find a good position with the blankets and pillows, etc., will raise heart rate.

But once you're lying still, the oximeter will record what your pulse is, as well, and you can look at the objective data after you upload it to your computer.

If you truly had a heart problem that was causing an accelerated pulse, this would happen while you were up and about.

A heart problem doesn't wait until you've just gotten into bed to start speeding up your pulse, especially since lying down reduces your body's energy needs – save for that transient adjustment to your new position that Dr. Besser pointed out or slugging the pillows.

Lying down to go to sleep may also be a conditioned stimulus to anxiety – thinking about your day, as Dr. Besser also pointed out.

Or, it may be the next day that you're thinking about that gets your heart beating faster than usual.

Solutions

• A full cardiac workup that comes out negative for any problems will really put your mind at ease.

Shutterstock/forestpath

• However, you may still find your heart beats fast the moment you lie down for sleep – due to anxiety about the issue despite normal test results, and/or anxiety about your life.

• Before going to bed, get ready for the next day as much as possible.

• Lay out next day's clothes.

• Prepare next day's breakfast as much as you can, such as cracking and mixing the eggs and seasoning them, then placing them in a covered bowl in the refrigerator. Set out the pan and spatula, plates and silverware, etc.

• Prepare next day's lunch.

• Set snail mail you want to send at your front door so you won't forget it.

• Write out a to-do list of tasks you must get done the next day.

This way, by the time you lie down to go to sleep, your anxiety levels will be reduced, and your heart should not be beating so fast anymore due to anxiety.

Dr. Besser provides comprehensive family care, treating common and acute primary conditions like diabetes and hypertension. Her ongoing approach allows her the opportunity to provide accurate and critical diagnoses of more complex conditions and disorders.
Lorra Garrick has been covering medical, fitness and cybersecurity topics for many years, having written thousands of articles for print magazines and websites, including as a ghostwriter. She's also a former ACE-certified personal trainer.
Top image: Shutterstock/Supawadee56 beating fast