As a clinician, my patients often tell me “I know I should drink more water.” But, do we really know how much water we should drink per day? From the studies on this subject I would say that it depends on many factors. No study directly answers the question of how much water to drink, but we can get some guidelines. Read on to find out what the studies say is the least requirement. As well as at least one good reason that you might want to increase your intake.
In healthy adults, certain conditions within the body are tightly controlled. These conditions include:
- body temperature
- blood sugar level
- the body’s water content
We take in water as fluids and within foods. We lose water from the lungs when we breathe, in urine and through sweating. Often with wide day to day variations in intake and losses. Yet, we have an amazing ability to regulate the amount of water in the body.
So, any calculation of water need must account for several influencing factors. Such as:
- climate or environment – hotter climates increase demand for water
- amount of physical activity – more strenuous activity increase the need for water
- diet – some foods contain a large amount of water, which can reduce the amount of fluid needed
This study suggests an average, sedentary adult should drink at least 1500mls water per day. However, strenuous physical exercise and hotter climates could easily double this need.
However, there may be further reason to increase your daily water intake. In this study, researchers asked healthy young women to record their food and drink for five days. The women carried out with their usual daily activities while taking part. They also filled in a quesionnaire about their mood and level of thirst.
Results were sorted into low, moderate and high levels of water intake. Low intake was around 1500ml total water intake per day. Whilst high was around double that at about 3000ml total water intake per day.
The questionnaires revealed that there was no difference in thirst between the groups. Yet results showed that higher total water intake was associated with better mood. In fact, the women that had the lowest water intake were twice as moody as those with the higher water intake.
Did drinking more water improve the participants mood? Or did happier ladies tend to drink more water? Researchers could not say. Yet, previous studies show that low fluid intake corresponds with more fatigue and tension.
So, since we do know that people with a more positive outlook on life generally appear to have better health and longevity – drink more water and be happy!