How much should your daily intake of water be? How do you know if you’re dehydrated? Why is it so important to stay hydrated?
Our Medical Director, Jamie Brosch, answers a few frequently asked questions about hydration.
This really depends on a number of variable factors such as your build, level of activity, air temperature, for example. A good general baseline though is 2 litres for women, 2.5 litres for men. And this should come from a combination of food as well as drinks, between 70-80% from drinks, the rest from foods.
Thirst is the main marker, but as with hunger we can be distracted from thirst and may not feel really thirsty until we have started to become dehydrated. It is more of an issue during intense exercise where the signals may be more confused and the impact is even greater.
Generally, our kidneys are very good at conserving water when necessary by concentrating our urine. It is only a problem if urine becomes very dark. Other signs of dehydration such as skin changes tender to be late changes which are unlikely in someone who is well. Symptoms such as tiredness and headache may be worsened by dehydration but are not reliable markers.
It is rarely harmful to drink a little too much, so drinking more water if you suspect you need to is the way to go.
As a general rule, like eating, it's better to drink little and often. It is also a good habit to have a reasonable volume of fluid at mealtimes.
Staying well hydrated helps to keep the 60% of your body weight which is fluid with electrolytes (salts) at the optimum concentration for good function. Being well hydrated maintains adequate blood pressure and circulation, and helps to regulate body temperature, all of which help keep you healthy and well.
Sports drinks contain electrolytes to mimic the make-up of our body fluids. These are lost as sweat during intense activity. Replacing them probably helps sustain intense activity but this is only really necessary if exercising hard. Otherwise eating food will do this, better in some ways.
It is also possible that sports drinks are absorbed from the stomach more easily than water during intense exercise, particularly when eating is impossible - this is why this option is suited to long distance runners for example.
Generally though, plain water is fine most of the time.
Yes, but if your kidney function is normal you would need to drink high volumes quickly to overcome the capacity of the kidneys to get rid of the excess as urine.
There is a suggestion that drinking water at the start of a meal can increase feelings of satiety (fullness). Even if it isn’t certain, it is a good habit to ensure a regular intake.
Yes – sort of! There was a strong myth that you shouldn’t count any drinks such as tea, coffee or alcohol because of their diuretic effect (making you pass more urine than the equivalent amount of water).
Certainly large amounts of alcohol can lead to dehydration as part of the classic hangover. Whilst any fluid intake is better than none, it is better not to rely too heavily on these ‘diuretic’ drinks.
Soft drinks and juices can still count, but beware of the amount of sugar you may be consuming if you rely on them to stay hydrated.
You will pass more urine, but if you get it just right, you may not go more often. Concentrated urine irritates the bladder more which may lead to more trips to the toilet.
It certainly makes them more likely as there is less flow through the system, so bugs have more time to multiply and swim against the stream.
In summary, hydration is important when it comes to keeping healthy and well. The functioning of our entire body counts on it, so make sure you're getting enough water every day.
About Dr Jamie Brosch
Jamie was a founding director of Wiltshire Medical Services and became Medical Director for Medvivo Group when it was formed in 2013. He has 20 years of experience as a GP Principal in Wiltshire and continues to work as a sessional GP, which allows him to maintain full registration with the GMC and on the GP Performers List.
Jamie has always supported a holistic approach to general practice and is a strong advocate for the integration of physical and mental health services with the delivery of social care.
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