Hydration and travel

Travelling and holidaying in a warm or hot climate will usually increase our hydration needs.

blue In temperate climatic conditions the properly hydrated individual would lose an average of about 2−3 L of water from their bodies each day. This water loss is mainly via urine but sweating can also result in large water losses. We need to remember that the amount of water lost through sweating will be increased in hot and/or humid environments, especially in the presence of air currents or during increased physical activity.1 This water needs to be replaced for us to remain properly hydrated.

green When travelling by plane, our bodies tend to dehydrate because air conditioning in the cabin makes the air drier than in a typical indoor environment. Dehydration during long flights, coupled with lack of movement, increases the risk of deep vein thrombosis.2

orange Travelling in a hot car can lead to sweating and high water loss. Even in air-conditioned vehicles, water loss can be increased on long journeys. It is very important to stay properly hydrated whilst driving as even mild levels of dehydration can impair physical and brain performance, potentially affecting concentration and increasing sleepiness.1 Frequent non-alcoholic drinks may help to prevent road fatigue.

Tips for staying properly hydrating when travelling

• Get to know your usual hydration needs. You can then adjust them for the journey, your destination’s climate and how active you will be there.

• Making sure that you pass pale coloured urine regularly will ensure that you stay well hydrated. If you do not, drink more.

• Remember that all non-alcoholic drinks help with hydration (e.g. water, milk, fruit juice, soft drinks) and many foods contribute to your total water intake (e.g. fruit and vegetables)

If you would like more information about the themes discussed in this article, the ICASH website contains a range of materials which explore hydration-related subjects in more detail.

1. EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA); Scientific Opinion on Dietary reference values for water. EFSA Journal 2010; 8(3):1459. Available online: www.efsa.europa.eu/en/efsajournal/pub/1459.htm
2. Hamada K, Doi T, Sakura M, Matsumoto K, Yanagisawa K, Suzuki T, et al. Effects of Hydration on Fluid Balance and Lower-Extremity Blood Viscosity During Long Airplane Flights. JAMA 2002; 287: 844-5.