How much water should I be drinking daily?

drinking water

Your body is primarily made up of water which gets lost throughout the day through various methods. Whether sweating due to exercising or heat, to diarrhoea and urine.

But how much do you really need? There is no clear defined answer. Some suggest the 8×8 rule, while others suggest drinking 3 to 4 litres plus per day. Your water requirements are determined by several factors including your overall health, activity levels and environment [source].

Why is water so important to your health?

Water provides vital functions for the survival of our body and makes up anywhere from 60 to 70% of your body weight. 

Water helps every cell in your body and helps overall well-being by:

  • Getting rid of waste and toxins (through urination and perspiration), 
  • Helps regulate your body temperature, 
  • Supports in digestion by breaking down foods more easily,
  • Helps keep your skin bright,
  • Helps maintain focus and concentration

How much water do you need?

The NHS (UK National Health Service) recommends six to eight glasses of water as still be best (1.2 litres) [NHS Source].  The general rule here is to drink 8 glasses of 8oz of water – otherwise known as the 8×8 rule. 

But others suggest taking more. The Institute of Medicine recommends men taking about 3 litres of fluid per day and women about 2 litres or more, particularly if pregnant or breastfeeding [source IOM  and source2].

If you live in a hot climate or do heavy activities/exercise including running or walking around a lot, then you should be drinking more to stay hydrated. 

The key is to keep hydrated and consume at least enough water to replace normal water loss. 

Do I need to drink only water to stay hydrated?

No! The key is to keep hydrated, so you don’t need to rely on water only in order to achieve this. 

Water is present in foods. Watermelon, Apple and Spinach are rich in water. 

Drinks such as juice and teas are also composed of water to a large degree. But not all drinks are made the same! Don’t overdo the sugary drinks or caffeinated beverages such as coffee & tea. These can be more calorie dense and run the risk of dehydrating your body.

Will Caffeinated drinks dehydrate me?

Caffeine based beverages can contribute to your daily fluid requirement and while they have a diuretic effect (causing the urge to urinate) – Mayo Clinic reports there to be no increased risk of dehydration

This depends on how many teas and coffees you’re consuming per day.  If you find yourself urinating more frequently – consuming fewer caffeine beverages may help quench your thirst and feeling of dehydration. 

How do I know when I need more water? 

Our body is a complex machine which has internal mechanisms built in to give signs of dehydration. 

Feelings of dryness in the mouth, fatigue and lethargy as well as headaches are all symptoms of water dehydration. 

Common symptoms of dehydration (or early symptoms of dehydration) include [NHS]: 

  • Feeling thirsty / dry mouth and lips 
  • Dark yellow and strong-smelling urine – this is the biggest indication your body is water-deprived
  • Dizzy / light-headedness / headaches – dehydration causes brain tissue to lose water causing your brain to shrink (your brain is around 73% water) [source] and also reduces your blood flow and oxygen to your brain causing inflammation.
  • Lack of energy – fatigue and lethargy are signs of your body craving water. This is because dehydration causes your blood pressure to drop – reducing blood flow to the brain and causing you to feel sleepier and tired
  • Constipation – not enough fluid in your body can make it harder to pass stool 

Dehydration can happen more easily if you suffer with the following conditions [NHS]:

  • Diabetes
  • Diarrhoea – which results in excess water leaving your body
  • Prolonged exposure to the sun – leading to excessive perspiration to cool down
  • Exercise – causing your body to sweat to cool down

When should I drink water?

Timing your water intake correctly can help prevent common problems including stomach pains, IBS, fatigue, high-blood-pressure and constipation [source].

A great breakdown of when you should be drinking water is provided by Katherine Fluor on Camille Styles.

The best times to drink half a glass to a full glass include: 

  • Right when you wake up
  • Before eating
  • Before an after working out
  • Before going to bed
  • And generally, whenever you feel thirsty

But there is a risk of drinking too much. Drinking too much water can lead to. Condition called “hyponatremia” which is where your blood sodium levels drop to dangerous levels [source]. 

If your urine is often clear – that could be a sign you’re drinking too much too soon. Instead, space out your drinking habits to 500ml max intake every hour (if possible).