Employers are required by law to provide workers with access to drinking water, yet many employees remain unclear about hydration. What is the “right” amount to drink every day and, crucially, how can it vary according to the type of work carried out and the environment in which the work takes place? Sarah Silcox investigates.
Hydration is an important workplace issue, according to Dr Emma Derbyshire, an adviser to the Natural Hydration Council (NHC), a not-for-profit organisation researching the science behind hydration, funded primarily by its members in the UK bottled water industry.
“The evidence is that being hydrated is associated with better cognition and mental performance, and helps combat tiredness and fatigue, all of which can help organisational productivity”, Derbyshire argues. “Also, there is a legal requirement on employers to provide access to water”.
Various official bodies produce guidance on the recommended daily intake of fluids, when the message is inconsistent it can make it difficult for OH professionals and others to get the hydration message across.
Derbyshire agrees that the different sets of recommendations can appear confusing, but she argues that those published by the European Food Safety Authority should be the ones to go to: “Their guidance of 2.5 litres for men and two litres or women a day should be used. Of course, the guidelines talk about ‘fluids’, which can include tea and coffee and other drinks, but the NHC believes that water is the purest form of hydration as it is calorie and energy free – vital given concerns about growing levels of obesity”, she adds.
Examining the European guidelines in more detail suggests that 70% to 80% of recommended fluid intake comes from drinks (as opposed to foods).
“This boils down to a headline figure of eight glasses of water a day, which can appear daunting and open to misinterpretation. Realistically, people should be aiming to drink about six glasses of water and a couple of cups of tea or coffee, or something similar, a day”, Derbyshire suggests.
How much water should we drink?
Water is essential for life and an individual’s health; a regular intake is necessary for maintaining the body’s fluid balance. However, it is difficult to define a recommended water intake for everyone, as a range of factors can affect an individual’s need, such as age and gender, but also levels of physical activity and climate.
The European Food Safety Authority’s (EFSA) panel on dietetic products, nutrition and allergies recommends daily intakes of two and 2.5 litres for women and men respectively.
However, it adds that these adequate intakes apply only to conditions of moderate environmental temperature and moderate physical activity levels. Water loss under extreme conditions (both due to temperature and physical exercise) can amount to eight litres a day and must be replaced with appropriate amounts.
UK-based authorities tend to take their lead from the EFSA, with the NHS recommending that women should drink eight 200ml glasses and men 10 glasses of fluid a day. The British Nutrition Foundation provides guidelines on the type of fluid to drink, concluding that individuals should drink “plenty” of water.
The Health and Safety Executive (HSE) recommends that, when working hard or at a high rate in heat or stress conditions, employees should consume around 250ml (half a pint) of water every 15 minutes.
However, the HSE recognises that this approach may not be practical due to the nature of the task, for example, having to wear protective equipment that restricts the ability to drink, or working in an industry where hygiene requirements prevent the consumption of food or drink. “In these circumstances, an alternative approach is drinking 500ml of water per hour before work commences and encouraging the drinking of 500ml of water during their rest periods”, HSE guidance suggests.
It is possible to drink too much water, leading to hyponatraemic, hypo-osmolar water intoxication (low levels of sodium in the blood) with cerebral oedema. But the EFSA concludes: “No maximum daily amount of water than can be tolerated by a population group can be defined, without taking into account individual and environmental factors.”
Sources: Scientific Opinion on Dietary Reference Values for water, EFSA Journal 2010; 8(3), p.1459.
OH role in hydration
Occupational health and HR professionals have a role in ensuring that the message around the importance of hydration is understood and the guidelines on recommended intake are communicated consistently.
“These functions should also be prompting employees to take a break to drink water, not just tea and coffee, and also ensuring that the organisation provides access to an appealing supply, not from a rather grimy-looking water cooler”, Derbyshire emphasises.
The message to employees should be to drink water regularly in small amounts throughout the working day and not just at mealtimes or in response to thirst.
One of the key roles of OH is to ensure that groups of workers at risk of “involuntary dehydration” can access water. An employee’s ability to access water depends on a range of factors, including their job role and occupation.
For example, medical staff working long hours in an operating theatre in a single session, or call centre staff, might find it hard to take a break in order to drink, even if the facility exists.
Similarly, employees who are required to wear heavy protective clothing at work, or who work in extreme temperatures may need to drink more fluids than the standard recommended intake. Both of these types of workers are potentially at risk of dehydration.
Working for relatively long periods in a hot environment will increase an individual’s rate of water loss as a result of sweating and raised respiration.
How fast workers sweat will depend on conditions in the working environment, but those wearing heavy protective clothing can lose up to 2.25 litres of fluid an hour.
Fluid loss at this rate can quickly lead to dehydration if not replaced, but also needs to be accompanied by the evaporation of moisture through the skin, which might not be possible if the employee is wearing protective clothing.
Hot working conditions may also lead to changes in an employee’s respiration, affecting levels of hydration. For example, an individual might pant in order to get rid of excess heat, leading to hyperventilation, in turn prompting dehydration as excessive amounts of fluid are lost in exhaled air.
OH professionals need to educate employees and line managers about the best ways to rehydrate, particularly targeting groups working in hot environments. The Royal College of Nursing recommends that frequent rehydration with smaller volumes of fluid is better than one large intake of liquid and that this should be accompanied by a balanced diet to replace lost salts.
OH professionals should consider carrying out a risk assessment for heat stress if appropriate. Possible solutions for reducing the risk recommended by the Health and Safety Executive (HSE) include:
Hydration and work: the law
The law requires employers to provide drinking water at work and to ensure that it is:
- Free from contamination and preferably from the public water supply; bottled water dispensers are acceptable as a secondary supply. Drinking water should not be sited in an area where contamination is likely, for example, in a workshop where hazardous materials are handled, or in a washroom.
- Easily accessible by all employees, and marked by an appropriate sign.
- In adequate supply, taking into consideration the temperature of the working environment and type of work activity.
- Provided via cups or a drinking fountain.
- control the temperature using engineering solutions (for example, fans and air conditioning);
- provide mechanical aids to reduce the work rate;
- prevent dehydration by providing coolwater in the workplace and encourage workers to drink it frequently, in small amounts, before, during (although this might not be possible in some situations) and after working;
- provide personal protective equipment that protects workers in certain hot environments;
- awareness training, particularly for new and young workers, on the symptoms of dehydration, safe working practices and emergency procedures;
- allow workers to acclimatise to the working environment and identify those ready to work in hot conditions;
- use the advice of occupational health professionals to identify employees who are more susceptible to heat stress, for example, because of an illness or health condition; and
- after mitigating risk using the above controls, monitor the health of those still exposed to residual risk of heat stress.
Of course, it is not only those working in hot environments who are at risk of dehydration; employees working in cold environments can also lose excessive amounts of fluid due to the high rate of energy used to keep warm, or because they are required to wear heavy protective clothing.
Some indoor environments may also present risks of excess fluid loss, for example, where humidity is high due to poor air circulation, or where there are a large number of computers in a small space. Employees working in these environments also need to understand that maintaining good hydration levels is important for health.
“Ultimately, promoting the purpose of hydration is a win win for employers, as hydrated employees are more productive and mentally alert”, Derbyshire concludes.