Dr. Myers, can you tell me why I sometimes wake up at night sweating and feeling my heart race?

I spoke with a woman in my office today who had a laparoscopic Roux en-Y gastric bypass by me over a year ago. She has lost nearly all of her weight and was very pleased with her outcome. However, she was bothered by episodes that occurred occasionally during the night that were concerning to her. Her symptoms included waking up from sleep wet with sweat, heart racing, feeling light headed, nauseated and mentally foggy.
It is important to explain that she is on no diabetic medication.
These symptoms may sound familiar to some gastric bypass patients since it sounds very much like symptoms they experience after eating too much carbohydrate which is called “dumping syndrome”.
Dumping syndrome is the result of absorbing a lot of sugar from a large amount of carbohydrate that is taken in the diet. With the sugar rise in the blood stream the insulin goes up as well. After the sugar is gone the insulin is still too high and the sugar goes too low which is called hypoglycemia. Low blood sugar causes the same symptoms this woman described.
However this patient stated that she had not eaten since 7 PM the evening before. And therefore could not be related to eating too many carbs.
A gastric bypass operation not only bypasses the stomach but also bypasses some of the small intestine including the first part of the small intestine called the duodenum. In addition the time it takes for food to arrive at the last portion of the small intestine is shortened because of the bypass of the stomach and the shortening of the small intestine. The result of these changes after a gastric bypass is that a patient puts out more insulin after ingesting carbohydrates than they did before the operation. This is because certain hormone like substance are released into the bloood stream from the intestine that causes the pancrease to release more insulin. This is especially important for diabetic patients since it helps them to get off insulin shots and diabetic pills.
This woman also is experiencing symptoms from a low blood sugar. Her difficulty is that she is waiting too long after a meal to have something more to eat. And since she produces more insulin to a carbohydrate meal she is using up her sugar and eventually the blood sugar is so low it caused symptoms. This problem may happen during the day as well if a person that had a gastric bypass waits too long before having another meal or snack. Usually the time between meals should be less than 4 hours while they are awake.
I believe the best treatment for this problem is a series of dietary changes. I suggested that she begin by decreasing the overall carbohydrate intake to smooth out the highs and lows. Second, she should eat later in the evening before going to bed and the meal or snack should have protein as well as carbohydrate to lengthen the absorption. Crackers and peanut butter or cheese would be a good choice. Finally I encouraged her to eat or snack more frequently about every 2 to 3 hours during the waking hours to decrease the likelihood of these symptoms occurring during the day.
It has been my experience that patients respond to these dietary changes very well with resolution of their symptoms. To this date I have not found additional therapy necessary for any of my patients.
Want to make a comment or ask your question? Click on the word ”comments” at the end of this posting.
Want to have new postings I make to this blog sent free and automatically to your email? It takes less than 30 seconds. 1). Enter your email address where requested on the left side of this blog.2)Click on “subscribe” and follow directions to prevent spam.3). Click on “Complete Subscription Request”. It’s just that easy! Your email will not be shared or used for any other contact.