Hydration is a crucial component of nutrition but is often overlooked when making a fuelling plan. Being dehydrated can lead to a 10% decrease in performance. This week, we speak with Chris Froome OBE, four-time winner of the Tour de France, and Dr Lewis James of Loughborough University, an expert on hydration. Make a strategy and clear nutrition plan. You should execute a plan that includes hydration. Beyond what you will eat and drink, you should know the logistics of where and when you will consume food and beverages. How often should you be finishing a 500ml bottle? Where will you stop to refill it? Failing to plan means planning to fail. The impact of hydration on performance is huge. Hydration is equally important to eating. Dehydration can result in a 10% decrease in performance! This is true in all temperatures, but especially in hot climates. It is easy to forget to drink, especially when cooler temperatures dull your thirst, so include hydration in your planning for before, during and after a ride. How much should you drink? This depends on how much you weigh, what your water to weight ratio is in your body and your sweat rate. You can measure this by weighing yourself before and after training sessions. The amount of weight you lose during the session is the amount of water you lost in sweat. You should rehydrate with 1.5 times the amount you lost – if you are 1 kg lighter at the end of your ride, drink 1.5 litres of water to rehydrate within 30-60 minutes of completing your exercise. Dehydration negatively impacts your physical and mental performance. Endurance activities and cognition are impaired with even slight dehydration. Cognitive decisions are important for athlete performance and can make the difference in how well you perform, so ensure you keep your brain and body functioning smoothly! The more, longer and harder you train, the more important this becomes. Hydrating means replacing salt and electrolytes lost, too. Our bodies sweat to cool down our core temperature that increases when our bodies create energy in the form of heat during exercise. This heat must be released, so beads of sweat form and evaporate on our skin to cool us down. A hydration plan must incorporate replacing the sodium chloride and electrolytes you lose in sweat so the water you drink can be absorbed properly. Chris and Lewis recommend fuelling with a combination of water, hydration drinks like SiS Hydro Tablets, and carbohydrate drinks like Beta Fuel for endurance exercise. To hear the full interview about how Chris fuelled four Tour de France wins, and the ‘blind trials’ Lewis ran that showed hydrating is not a placebo effect, listen here. Follow us on social media @scienceinsport and read more articles on topics we have discussed on the podcast before here! Written By Julia Deufel - content writer and consultant Julia runs her own marketing consultancy, working with businesses and non-profits in education, nutrition, fitness and the arts. She also teaches a blend of HIIT and Pilates she developed and is an avid indoor cyclist. Julia is an advocate of effective altruism and believes in the power of sport to change lives.