A very common mistake: Some people take it “to alkalize blood.” The blood maintains its pH between 7.35 and 7.45 automatically thanks to the kidneys and lungs. No homemade drink can change that unless you are very sick. If anyone promises to cure cancer with this, walk away.
Responsible conclusion: Water with baking soda and lemon is a good point resource for acidity or to relieve an excess of acids in the body. But it’s not a miraculous potion. Use it in moderation, respect the doses and, above all, listen to your body. If heartburn is common (more than twice a week), do not self-medicate: consult a gastroenterologist. What really alkalizes the body in the long term are salads and legumes, not baking soda.