The research carried out a few years ago seems to suggest that even mild dehydration doubles the number of mistakes made by drivers. In this respect, dehydrated drivers are as bad as the intoxicated ones. The problem returns especially in summer when the temperature are high.
There is a common view that many drivers avoid drinking beverages during long journeys to avoid toilet breaks. We know, however, that even mild dehydration may cause symptoms such as headache, fatigue and lethargy” – explained Jane Holdsworth (European Hydration Institute; EHI), commenting on the results.
We’d like to remind that the research which result was published in the medical journal Physiology and Behaviour revealed that when it comes to the number of mistakes made by drivers, even mild dehydration can be likened to driving drunk. Researchers from Loughborough University conducted a series of tests involving male drivers. Under normal hydration conditions there were 47 traffic accidents. Dehydration resulted in an increase of this number by more than twice. There were 101 accidents (a similar value can be expected when the drivers are under the influence of drugs or alcohol). These events included leaving the lane, late deceleration and driving on or crossing the lines which separate the lanes or the roadside.
The level of dehydration analysed in the research was low, comparable to the level of dehydration occurring after a day of hard work with limited access to drinks.
We all condemn driving under influence but usually do not reflect on the impact of other factors on our skills on the road, while one of them is the lack of adequate hydration. There is no doubt that driving under the influence of alcohol or drugs increases the risk of an accident. Our findings, however, show previously unknown dangers and indicate the need to encourage drivers to properly hydrate. To better explain the consequences of our findings, it is worth noting that in terms of the number of mistakes made by the researched drivers, they behaved similarly to people with blood alcohol concentration of 0.8 per mille, an amount currently allowed by the British law. In other words, insufficiently hydrated drivers make the same amount of mistakes as the drunk ones” – said prof. Ron Maughan of Loughborough University who supervised the research (the research was conducted at the Department of Sports, Physical Exercise and Health Sciences of Loughborough University).
Recently, as part of the „Beverage, the best fuel” campaign the Spanish automobilklub reminded that dehydration increases aggressiveness of drivers by 66% and reduces their concentration by 27%. Due to being dehydrated by one-third they are more likely to go off the lane and the fatigue appears in them in half the usual time (source: Diario de Transporte).
Given that the mistakes of drivers are the cause of too many collisions and accidents, EHI calls for caution and attention to proper hydration before heading out, especially in the hot summer months. According to the recommendations of the European Food Safety Authority (EFSA), healthy adults should drink an average of 2-2.5 liters a day (for mild temperatures and average physical activity). According to EHI, 20-30% of the water demand is covered by the food, while 70-80% should be provided by drinks (all of them, not just pure water).
Experts emphasise how important it is to get into the habit of drinking regularly throughout the day. The idea is not only to follow the feeling of thirst. It is recommended that during a moderate physical effort one glass (250 mL) of fluids should be drunk per hour. It doesn’t have to be water. Juices, milk or tea are also an effective source of hydration.