My textbooks says:
It may be noted that although lithium has most negative E0 value (Table 10.1), its reaction with water is less vigorous than that of sodium which has the least negative E0 value among the alkali metals. This behaviour of lithium is attributed to its small size and very high hydration energy. Other metals of the group react explosively with water.
So, basically if Li has more negative SRP value it basically means it's a very good reducing agent, right? Water in the presence of a strong reducing agent starts acting as an oxidising agent. But when water combines with Li, the hydration energy released is very high due to very low charge density on Li. So how would any of that cause the reaction of Li with water to be any less vigorous than Na?