Water is a nutrient that is essential to human health. The human body is made up of about 60% water and is required for many processes, including metabolism, digestion, and waste elimination.
You’re probably familiar with the importance of hydration as it relates to nutrition and fitness, but did you know dehydration can affect your sleep? Emerging scientific evidence shows that dehydration may impact sleep quality, and conversely, lack of sleep can increase the risk of dehydration.
However, drink too much water, and you’ll be up in the middle of the night to go to the bathroom.
Finding a balance between too much and too little water is important for optimal sleep and overall health.
What the research says
While there aren’t many studies examining the relationship between hydration and sleep, the research that exists does indicate some relationship between the two. People who sleep for shorter durations tend to be more dehydrated.
Water protects organs and tissues, carries nutrients and oxygen to cells, lubricates joints, and decreases the kidney and liver’s burden by flushing out waste products. Because water plays a significant role in many bodily functions, dehydration can affect sleep.
In a study that compared adults in both China and the United States, the participants who only slept six hours were significantly more dehydrated than participants who slept a full eight hours.
Although this study does not provide evidence for causality, it does have some significance, given that two different cultures were observed in the study.
Another study, however, indicated that dehydration does not affect sleep quality. However, this study had a small sample size of only twelve adults, and the authors suggested that more research on the topic is needed.
There are also biological reasons that may explain the relationship between sleep and dehydration. Most of the body’s water is lost through sweating and urination. Water is also lost from respiration. Over a 24-hour period, the body can lose somewhere between 300 and 400 ml of water from breathing. Most of this loss occurs during sleep, and breathing through the mouth can increase these losses.
During the sleep cycle, no water is consumed to replenish the water loss. The body’s internal clock, also known as the circadian rhythm, fires up and secretes the hormone vasopressin, which causes water retention.
If sleep duration is shortened, vasopressin may not be excreted due to the disruption of this automatic biological mechanism. When this occurs, water is not retained, and thereby can cause dehydration.
Does dehydration negatively impact sleep?
From the research, scientists believe that shortened sleep duration can increase dehydration, but can dehydration cause poor sleep?
The symptoms of dehydration alone can negatively impact your sleep. Symptoms of dehydration include headache, muscle spasms and cramping, dry mouth, and excessive thirst.
If you’ve ever had a charlie horse, you know that muscle spasms and cramping may cause you to wake suddenly in the middle of the night.
Headaches resulting from dehydration can make it difficult to fall asleep, while a dry mouth and excessive thirst can wake you or cause discomfort during sleep.
How to prevent dehydration
To prevent your sleep from being impacted by dehydration, and prevent dehydration caused by poor sleep, try the following tips:
Stay hydrated while you’re awake
If you drink plenty of water during the day, you won’t have to worry about drinking too much before bed. If you often feel excessively thirsty at bedtime, you probably didn’t drink enough during the day.
Tips to stay hydrated
- Sip water frequently and set alarms to remind you to drink if you’re forgetful
- Carry a water bottle to make water easy to drink and accessible
- Add a clean electrolytes powder like Citrus Nakedade to your water to help you stay hydrated and replenish electrolyte loss from sweating
- Eat fruits and vegetables with a high water content (cucumbers, apples, celery, watermelon)
Optimise your sleep environment
Setting your sleep environment can help improve sleep quality and duration, which may help decrease dehydration. Keep the room at a cooler temperature, minimise outside light and sound, and keep the room tidy and organised. These things may have some impact on sleep quality.
Prevent nighttime urination
Avoid any beverage consumption one to two hours before bed. If you’re thirsty, it’s fine to take a couple of sips of water, but try not to drink it in large amounts. Stay away from caffeine or alcohol at night. Both fluids increase urination due to their diuretic effects. Lastly, empty your bladder before you get into bed.
Recent research indicates that there is some relationship between hydration and sleep. While more research is needed, scientists believe that poor sleep quality and short sleep duration can increase the chance of dehydration. They also believe that dehydration can negatively impact sleep. Stay hydrated by drinking plenty of water throughout the day and aiming for eight 8 hours of sleep nightly.