By Virginia Gurley, MD, MPH
MB (Marc Braman, MD, MPH):
Continuing with sleep 101, our topic this session is “Sleep and Fluids”. Thank you for joining us, Dr. Gurley.
VG (Virginia Gurley, MD, MPH):
Thank you, Dr. Braman.
MB:
So do fluids or what we drink affect our sleep?
VG:
Yes, what you drink and when you drink it has a strong effect on how well you sleep. Most people know that drinking caffeinated drinks in the late afternoon and evening will delay getting to sleep, but other beverages like alcohol, salty soup, energy drinks, or just not drinking enough water during the day can have a negative effect on your sleep.
MB:
Okay, wow, so obviously caffeine wakes us up. That’s why we drink coffee in the morning, but doesn’t alcohol relax us? Wouldn’t that actually help us sleep?
VG:
You would think so, and most people believe alcohol makes it easier to fall asleep, but studies have shown that alcohol blocks melatonin secretion in the brain and actually delays the onset of restorative sleep. And like caffeine and coffee, tea and energy drinks, the later you drink it the more it will delay falling asleep. So if you do drink alcohol, please drink responsibly, and it’s best not to have alcohol later than 6:00pm or no later than 3-4 hours before bedtime.
MB:
Okay, that sounds like it would take some significant changes for many people. Does alcohol create any sleep problems other than making it just hard to fall asleep?
VG:
Yeah, so alcohol can also make it harder to stay asleep because it makes your kidneys more active, and you’re more likely to need to use the bathroom in the middle of the night. And then some people have trouble getting back to sleep again.
MB:
Okay, so not such a good idea to crank your kidneys up right before we go to sleep. What about salty foods? You mentioned soup. Salty foods at night, what happens?
VG:
Well, salty soup is often very salty. And having soup at dinner, if it is salty, can make it hard to get to sleep because research has shown that salt makes your blood vessels stiffen. And it’s relaxation of the blood vessels in your skin that allows your skin to warm, and this is a key trigger for getting sleepy and falling asleep at night. So the blocking effect of salt is made even worse if you don’t drink enough water during the day.
MB:
Okay, so how does that work?
VG:
Well, like salty soup and foods, studies have shown that not drinking enough water during the day makes it hard for your blood vessels to relax, and your skin doesn’t get warm. And like with the salt, if your skin can’t warm up, then the temperature in the core of your body stays too warm and that interferes with sleep too.
MB:
So how much water should we drink and when?
VG:
You should try to drink at least 6 glasses of water by mid afternoon, and more if you exercise strenuously during the day. And, then you should try to drink another 2 or 3 glasses of water by the time you finish dinner, which, ideally you eat at least 3-4 hours before bedtime.
MB:
Okay, a little shift for many of us in the society.
VG:
Mhmm.
MB:
But we want to avoid drinking a lot of water right before bed, right?
VG:
Right, yes. The main problem with drinking a lot of water is you will probably wake up in the middle of the night because you need to go to the bathroom, and that’s not very helpful for getting restful sleep.
MB:
Excellent. So it looks like many of us are creating the problem to begin with. So we want to practice lifestyle medicine and treat the cause. Then we won’t need all the pills and procedures and we can feel good and enjoy life.
Thank you so much, Dr. Gurley!
VG:
Thank you, Dr. Braman!
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