A scientific study of the effect of alkaline water on hydration published in 2017 in the National Library of Medicine documents the following results of drinking alkaline water.
Drinking alkaline water in amounts of 4.0 l per day shows a positive effect on hydration status after anaerobic exercise with a significant decrease of specific urine gravity.
Intake of alkaline water also shows a positive effect on urine pH during the anaerobic test protocol, and much more efficient lactate utilization after the high-intensity interval exercise.
The consumption of alkaline water was associated with improved acid-base balance and hydration status. In contrast, subjects who consumed table water showed no changes over the same period of time. These results indicate that the habitual consumption of alkaline water may be a valuable nutritional vector influencing both acid-base balance and hydration status in active healthy adults.
These preliminary data demonstrated that consumption of alkaline water can improve anaerobic performance and post-exercise recovery.
Read the article here.
A separate study in the Journal of the International Society of Sports Nutrition also documented that, “After exercise-induced dehydration, consumption of the electrolyzed, high-pH water reduced high-shear viscosity by an average of 6.30% compared to 3.36% with standard purified water… After rehydration and recovery, the average percentage change for diastolic blood viscosity (measured at low-shear rate: 5 s-1) in subjects administered the control, standard bottled water (CON), was 5.43%, while the mean percent change for Alkaline water (ALK) was 9.35%.” Whole blood viscosity, the inherent resistance of blood to flow, was used as a measurement of intravascular hydration status.
In this study, those drinking alkaline water returned to their pre-exercise level of viscosity and associated blood pressure within one hour whereas those who drank regular bottled water still had not returned to their pre-exercise state after two hours. You may read the full study here.
I have been drinking alkaline water for several years and highly recommend it.