Assessing Hydration Status in the Workplace – Methodology

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Assessing Hydration Status in the Workplace – Methodology

In Part I of this blog-series we explored the hypothesis of the Loughborough study that assessed the hydration status of individuals in different work groups at the start and end of an eight-hour shift, as well as factors that potentially influenced their drinking of water at work such as access to beverages and toilet facilities.

The study was prompted by previous research which found that the majority of workers began their work day already dehydrated – a state well documented to adversely affect cognitive and mental performance.

A previous Loughborough study had already determined that even mild driver dehydration had led to increased driver errors; along with a reduction in perceived ability to concentrate and levels of awareness. In that study dehydration was purposefully achieved, whereas in this study the aim was not to manipulate or achieve dehydration in any of the subjects, but simply to examine what their natural hydration levels were if left unprompted.

In Part II we now consider the methodology of the study.


There were 156 participants in total. They ranged in age from 19 to 63 years with the average age 32 years; average height 1.74 metres; and average weight 77.6 kilograms. The gender split was 89 males and 67 females; and their split across work environments was 33 research students, 24 classroom taught students, 31 teachers, 15 security staff, 22 firefighters, 15 office workers and 16 catering staff.

Work Groups

The groups selected covered seven different work environments – the typical eight-hour work shift for each group (as per the published study is detailed below, along with any potential barriers to the drinking of water at work including whether or not there was limited access to toilet facilities.

  1. Research Students – University PhD and research students primarily based in an office environment but with visits to the laboratory for short periods of experimental work. No restriction on frequency and duration of break times and were able to eat and drink freely as they worked.
  1. Classroom Taught Students – University MSc students who participated in laboratory classes all day and therefore considered typical of a laboratory worker with restrictions on food and drink access. Food and water intake banned in the laboratory so subjects had to leave the laboratory to eat and drink. They were allowed a one-hour break for lunch.
  1. Teachers – Taught classes at secondary school for at least five hours per day with a small break of approximately 5 minutes after each one-hour lesson. One hour for lunch break and a 20-minute break at around 10am. Unable to leave the classroom and use toilet facilities whilst teaching classes. Unable to eat during classes but were able to consume their own drinks.
  1. Security – University security staff working a variety of shift patterns including night shifts. A 15-minute break before and after a 30-minute lunch/dinner break. Staff patrolled the university on foot, bike and in motorised vehicles and were able to drink freely during the shift when time permitted.
  1. Firefighters – Both day and night shifts were observed. Staff performed maintenance and practice drills throughout the day as well as having a physical activity session involving strength and aerobic activity in the onsite gym. Physical activity and therefore sweat losses were not recorded so that additional measures did not impact and influence a typical day. Average number of call outs was three per day. Were able to eat and drink freely when not performing drills or on call outs, when there was limited access to water.
  1. Office – Staff spent most of the day in front of computers apart from two small 15-minute breaks in the morning and afternoon and a 30-minute lunch break. Were able to eat and drink freely whilst working.
  1. Catering – Kitchen staff and chefs at a university canteen. They spent the majority of the shift on their feet with a large portion of work time (exact time unknown) spent in the kitchen preparing food. They were allowed two 15-minute breaks and a 30-minute break for lunch. Were able to drink, outside of scheduled break times, if time permitted.

Procedure – Prior to Shift

Subjects signed an informed consent form prior to their shift starting. They were asked about their typical water intake during a shift – what their access to drinks were and if there were any influences on drinking.

They were also asked to complete a six question survey relating to:

  1. Thirst: 0 = not at all thirsty, 100 = very thirsty
  2. Mouth Dryness: 0 = not at all dry, 100 = very dry
  3. Hunger: 0 = not at all hungry, 100 = very hungry
  4. Tiredness: 0 = not at all tired, 100 = very tired
  5. Concentration: 0 = not very well, 100 = very well
  6. Energy: 0 = no energy, 100 = lots of energy

Lastly, they provide a urine sample and were then measured for height and body mass – wearing one layer of loose fitting clothes, sans shoes. After which they were sent off to complete their work day as per normal.

Procedure – Post Shift

Upon completion of their shift participants provided another urine sample and were asked to answer the same six question survey relating to thirst, concentration etc. as before; along with what their access was to water at work, how much they drank, whether they felt thirsty and if so did they drink to quench their thirst. They were also asked to rate their concentration at the start, middle and end of their shift; as well as whether they felt they remained hydrated throughout their work day.

The participants were then free to leave.

In the third and concluding part of this blog series, we examine the results of the study – how many subjects actually began and ended their shift dehydrated and how that impacted on subjective feelings of thirst and concentration.

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