Is Your Bladder Keeping You Up at Night? It Could be Sleep Apnea.
Maybe you know what it’s like to get up too much going to the bathroom at night. Hour after hour, you’re out of bed and in the bathroom. If you are a man, you may think that it’s because of a prostate problem. For women and men, you may have read about Overactive Bladder (OAB) and think that could be the reason. But there is one cause of getting up at night to urinate that you may not know about. While Overactive Bladder is a common cause of nocturia (getting up more than one time per night), another regular cause that is infrequently diagnosed is obstructive sleep apnea. How can sleep apnea affect your bladder and is there anything that can be done about it? We’ll answer those questions and more in this week’s Bladder Blog.
What is Nocturia?
Nocturia mean waking up at night, more than once, in order to urinate. To be called nocturia, it needs to be the urge to urinate that actually wakes you up, not that you are having trouble sleeping and go to the bathroom while you are already up. Nocturia may be one of the most bothersome symptoms of frequent urination. For many, it can actually be dangerous. Those who have nocturia, especially if they are older, are more likely to have falls, which can result in serious injury.
Nocturia can result from several causes, with Overactive Bladder one of the most prevalent.. OAB reduces the capacity of your bladder to hold urine, resulting in more frequent trips to the bathroom. For many, this extends through the night. Prostate enlargement, often called benign prostatic hyperplasia (BPH), can also cause this issue in men. Blockage of the prostate can lead to irritation of the bladder, resulting in more frequent urination. Less commonly, BPH can mean that a man doesn’t empty his bladders well, also leading to more habitual urination. Men can have Overactive Bladder as well. Bad habits can also lead to constant trips to the bathroom at night. People who drink a lot of fluids (especially alcohol or caffeine) in the evening can find themselves up at night to urinate due to higher nighttime urine production. I even see some patients who will take a diuretic (a fluid pill) right before bedtime, which will often lead to a poor night’s sleep due to excess urine production.
The Role of Sleep Apnea
While all of these are common factors in nocturia, one often overlooked and, to many people, surprising cause is sleep apnea. Obstructive sleep apnea is caused by a temporary blockage of your breathing while sleeping. The muscles of your throat relax and the tissue around the throat and tongue block your airway. Because your chest is still trying to draw air into your lungs, blocking your airway in sleep apnea results in a lot of negative pressure in your chest as you try to breathe (try closing your throat and taking a breath). This negative pressure in your chest tends to cause more blood to return from the veins to your heart (the right atrium). When this part of your heart expands from the extra blood, it releases a hormone (atrial natriuretic peptide) that makes you make more urine. The body thinks there is too much blood volume because the atrium is dilated (as if you drank a lot of extra fluid) and it tries to get rid of the excess. So, patients with obstructive sleep apnea make too much urine at night. We call making too much urine at night nocturnal polyuria.
What is Nocturnal Polyuria?
Patients with nocturnal polyuria make too much urine at night and, as a result, fill their bladders more quickly than they should. This often leads to constantly waking up to go to the bathroom. Normally for young people, no more than 20% of your daily urine production should come while you are asleep. Even though most people sleep for about 1/3 of the day, the brain should send a signal to the kidneys to decrease urine output while you sleep. So it’s normal to make less urine at night than during the day. In older patients, the message isn’t as effective, but still less than 33% is more normal. Patients who exceed this are said to have nocturnal polyuria, meaning they release too much urine at night. This is easily diagnosed by having you keep a diary for several nights to measure how much urine you make during the night compared to the day. It is not unusual in my practice to see patients who make more than 60% of their urine at night while they are trying to sleep. No wonder they are up so much.
Treatment Helps
There are other causes of nocturnal polyuria, of course. Drinking fluids at night or taking a fluid pill at bedtime, as mentioned above, can also produce the same issue. But obstructive sleep apnea is often not recognized as the cause by people or their health providers. The encouraging news is that treatment of the sleep apnea such as with a mask providing continuous airway pressure (CPAP) not only treats the sleep apnea but also will reduce the urine production and the nocturia. So, next time you find yourself getting up that 3rd or 4th time at night, consider having an evaluation of whether you are making too much urine at night. If so, a test for sleep apnea may be in order.
