Sodium intake before exercise and its effects on performance in the heat



Considering the high temperatures at the beginning of the year in the southern hemisphere, especially in the Latin countries, the present publication aims to highlight the influence of sodium intake preceding the exercise on performance in the heat.

Several authors report that dehydration impairs performance in resistance exercise, especially in hot environments (Below et al., 1995, Coles and Luetkemeier 2005, Goulet et al., 2008, Hitchins et al., 1999 Sawka et al. in 2001, Walsh et al., 1994). Hydration during exercise can prevent or at least minimize dehydration occurring sweating derived from high effort during practice exercises (MAUGHAN, 1991).

To retard the development of dehydration during exercise, to exercise pre hyper hydration (HPE) may be employed (Hitchins, et al., 1999, Sims et al., 1997, Latzka et al., 1998). previous laboratory investigations suggest that the pure water consumption results in only a small fluid retention (Fruend, et al., 1995, Magal et al, 2003) and sodium consumption with predetermined volumes of water is more effective in promoting HPE (Coles and Luetkemeier, 2005 The Sims et al, 2007).

Thirst is the main stimulus that promotes the consumption of fluids. Thus, inducing the seat can increase fluid intake preceding the year and consequently the PEH, leading to improved performance and hydration status. Seat is stimulated in response vasopressin plasma hyperosmolarity (Ali-Rodrigues et al., 2004), which normally occurs only during dehydration, i.e., in a normal state, people seek only to hydrate in place of state.

In the current study Morris et al. (2015) conducted a study which assessed the issue addressed above, assessing changes in hydration levels, voluntary intake of fluids and performance of physically active men in three different conditions: no treatment, placebo and treatment with sodium in liquid solution.

The authors found a higher intake of fluids voluntarily by the participants when they realized treatment with sodium compared to placebo and untreated. The same happened with the water retention. With the increased fluid intake and fluid retention, therefore the authors observed a lower level of dehydration.

Regarding performance, use of a test against the clock on an exercise bike, which was used when treatment with sodium obtained better results in relation to other moments, suggesting the ability to improve performance.

However the applicability is made difficult by the fact that under natural conditions, the population has the habit of only hydrate when they are thirsty and ceasing consumption before they meet in a normal hydration stage (Greenleaf, 1992), and the indeed practitioners have difficulty finding the solution with an optimal amount of sodium without excess.

Allen et al. (2013) found results similar to those of Morris et al. (2015), however, evaluated individuals who were dehydrated order to use a solution having sodium as a way to prevent dehydration levels while Morris et al. (2015) evaluated individuals in a state of euhidratação.


According to the findings, the use of solutions of sodium are capable of increasing the seat and consequently the voluntary fluid consumption. Regarding the performance were also found positive results. We are waiting for further studies to know news.