How Much Water Do You Actually Need to Drink?
Your body needs water to survive. The human body is made up of ~70% water and every cell in your body requires a delicate balance of hydration to work efficiently and appropriately. Results include hydrated skin, lubricated muscles and joints, and body temperature regulation. You probably have heard the common line, “make sure to drink 8 cups of water a day”, but is this truly accurate? How could a petite female of 125 lbs require the same amount of water as a breastfeeding mom, or a football linebacker?
Here’s what some of the top medical institutions have to say:
Mayo Clinic recommends “About 15.5 cups (3.7 liters) of fluids a day for men. About 11.5 cups (2.7 liters) of fluids a day for women”.
NHS via their EatWell Guide recommends “6-8 cups per day”.
The National Academy of Medicine suggests “an adequate intake of daily fluids of about 13 cups and 9 cups for healthy men and women, respectively, with 1 cup equaling 8 ounces.  Higher amounts may be needed for those who are physically active or exposed to very warm climates”.
So we’ve got some guidance, but 6 cups of water is vastly easier to consume than almost 12 cups a day…so how much should we really aim for and why is it so important?
Here’s how I assist my clients in finding their hydration goals, when prioritizing pelvic floor function. Take half of body weight (in lbs) = their total fluid intake goal in ounces. Then multiply by .70 to find a daily water goal. The remaining number is the minimum amount of ounces they are to consume from other sources like coffee, tea, broth, food, etc.
Here’s an example: Let’s say you weigh 170 lbs.
170 / 2 = 85 Total fluid goal: 85 ounces of fluid intake per day.
85 x .70 = 59.5 Total water goal: ~60 ounces water per day (7.5 cups)
85 - 60 = 25 Remaining fluid goal: ~25 ounces via food, coffee, tea, etc. (3 cups)
However, we then need to consider some variables. If you live in a hot climate, are an endurance athlete, or a breastfeeding mother, you may need more water than the average sedentary person. Other variables to consider are medication intake, current illness (especially if you are experiencing diarrhea or vomiting), have a current UTI or kidney stone, are traveling to higher altitudes, or perform high intensity/endurance exercise/manual labor activities.
For some people, this information is overwhelming…especially if they are an individual who typically drinks minimal to no water. In these scenarios, my advice is to gradually increase water intake (carry a reusable water bottle with you at all times and take sips throughout the day), until your urine is a beautiful pastel yellow color. This indicates your body is not dehydrated.
I have also encountered clients on the opposite side of the spectrum…guzzling water nonstop throughout the day, resulting in frequent urination (1+ voids every hour) of which their urine is completely clear. This is an unnecessary amount of water to consume.
Here’s a great chart to refer to when assessing the color of your urine. I love providing this chart to my older clients in particular, because the sense of thirst declines as we age. Additionally, I’ve met some older individuals who purposefully dehydrate themselves so they won’t have to go through the work of going to the bathroom as frequently throughout the day. This increases their risk of serious medical issues such as dehydration and urinary tract infections.
The color matching is an easy way to hold us accountable to our fluid intake.
From a pelvic health physical therapist’s perspective, here’s why proper hydration is so important
BOWEL HEALTH: your bowels need enough water to ensure your poop is soft enough to pass without straining (+ addition of a squatty potty can work wonders!). Dehydration is the top cause of constipation.
When you consume food, it gets broken down into smaller and smaller pieces in the stomach as it enters the small intestine. The small intestine continues to break down these molecules and begins to absorb nutrients and electrolytes. By the time this waste enters the large intestine, it is mostly composed of unneeded fiber products and other waste material, but the body performs one last reabsorption of any remaining material that it can still utilize, pulling water and electrolytes from the matter back into the body. So if your body is already lacking water, and the large intestine reabsorbs the remaining bit of water it has been provided, the resulting stool is going to be hard, lumpy, dry, and difficult to pass (types 1-3 in the chart below)
BLADDER HEALTH: Urine is produced by our kidneys to help rid our body of waste products and toxins. As described above, the color of our urine can provide us with great information on hydration levels. One aspect that becomes important when treating people experiencing urinary frequency (voiding >9 times a day), urgency, urinary leakage, burning with urination, etc. is urine concentration.
The inner lining of the bladder is sensitive to the concentration of your urine. So if it’s darker colored, say you woke up and had 2 cups of coffee…you’re probably going to be peeing more frequently over the next few hours. However, if between every few swings of coffee, you took a sip or two of water, your urine concentration would be a bit more diluted, resulting in improved tolerance of the bladder and less frequent/urgent urination.
SEXUAL HEALTH: Short answer: proper hydration ensures sufficient lubrication, for both males and females.
If you have a vagina: Just like our skin can get dry when we're dehydrated, the vaginal mucosa can experience dryness as well. Ensuring sufficient water intake will result in sufficient vaginal lubrication to enhance the sexual experience. Additionally, to maintain vaginal health, the pH of the vagina must maintain balance.
If you have a penis: water contributes to production of pre-ejaculate, improved semen quality and quantity, enhancing libido levels and aids erection attainment (even for those experiencing ED!)
Like most medical related topics, there’s no black and white answer to the common question “how much water should we drink each day”. However, I hope this information provided some helpful advice to utilize. Every person’s necessary fluid intake level is based on individualized need, and the amount of water you may require one day can vary from the next depending on activity level, environmental factors, or current medical status.
If you, or a loved one you know is struggling to hydrate appropriately, please reach out to Dr. Mariah Lohr. It may just save you from an infection, constipation, or dehydration.