In previous posts on my blog, I discussed the importance of being well hydrated to prevent mental fatigue, and how to assess hydration level. The next question is what to drink during an adventure bike trip. Is plain water enough? Or should we add some electrolytes?

To answer this question, I have got in touch with Dr Ricardo Costa, an expert in sport nutrition at Coventry University. Furthermore, Ricardo has competed in the grueling Marathon des Sables. In this multi-stage ultra-marathon, athletes run 251 km (156 mi) at very high temperatures for six days. So I am sure Ricardo knows well the science of what to drink when sweating profusely for several days in a row.

This situation is similar to riding a motorbike for several days in hot weather. Although physical exertion is much less compared to a marathon, wearing an helmet and full riding gear greatly impairs sweat evaporation and its cooling effect. As a result, even more sweat is produced. So loss of body water through sweating is likely to be very significant during an adventure bike trip in hot weather.

Fortunately, with the exception of sodium, the concentration of electrolytes (e.g., potassium and magnesium) in our sweat is extremely low. This means that even during a multi-stage ultra-marathon in the heat (40C) serum electrolyte concentrations is maintained within normal range (Costa R, personal communication).

Based on this and other research, Ricardo's practical recommendation is simply to add a pinch of salt for every 500ml of water when we ride in hot weather and drink a lot to ensure a good hydration level. The extra salt does not have to be added to drinks. It can be added to food as well. This simple sodium supplementation will greatly reduce the risk of hyponatremia (meaning "low sodium"), a very rare but potentially fatal electrolyte deficiency that can occur when people sweat a lot and drink an excessive amount of water.

The above recommendation is valid for adventure bike riders consuming an adequate diet. However, data about weight loss suggest that many riders significantly reduce their food intake during an adventure bike trip. In these conditions, taking a daily multi-vitamin/mineral supplement that meets 100% RNI (e.g., Centrum or similar products) will act as a safe guard against other potential electrolyte deficiencies.

In future posts, I will discuss whether it is a good idea to add glucose or other soluble carbs to our drinks. In the meantime, please let me know about your experience with sport drinks if you have used them during an adventure bike trip.

Cheers

Sam