Water accounts for over half of your body's mass, and new research stresses that even mild dehydration can affect mood, cognition, and energy levels.

An article published in the American Journal of Clinical Nutrition by Professor David Benton and his team at Swansea University’s College of Human and Health Sciences has highlighted the importance for everyone in staying well hydrated.

Previous research within this field has found a loss of upwards of two percent of body mass through water loss leads to noticeable effects on your ability to function properly. This would typically apply to athletes undergoing extended periods of activity, or someone that has gone without fluids for several days. However, this new research has gone one step further, looking at how we may be affected by much lower levels of water loss, which we’d all experience in day-to-day life.

‌Commenting on the study, Benton said: “Roughly 60 percent of our body is made up of water, and this level is continually fluctuating, largely due to water loss through urine and sweat. Our research found that when losing only 0.6 percent of our body mass, there were noticeable effects on an individual’s memory, attention and mood.”

The study tested participants' memory and mood before and after sitting in a room heated to 30°C for four hours, and found a direct correlation between the change in a subject’s hydration level, and how well they performed in memory and mood tests. The study, which picked up body mass levels accurate to within 5g, found participants became less happy and felt that tasks presented to them would be harder to achieve, as their water levels reduced.

‌“This is particularly important for children, who may be reliant on others to fetch them a drink," adds Benton. "They lose water quicker than adults, as they’ve a higher surface area relevant to their size and tend to perspire more through regular activity."