The most powerful screen, a No. 15, will prevent the sun's UV tanning rays from reaching your skin. However, sunscreen products are sold in weaker concentrations. A No. 4 or 6 will probably allow some tanning but will prevent deep tanning or sunburn. When our thirst centers tell us to drink, they are responding to water depletion in our systems. Therefore, water is what we need.
Juices contain fruit sugar and vitamins, as well as water.
Therefore, juice drinks are appropriate substitutes, especially if a person is water-depleted from strenuous physical activity. Also, because of a high sugar-content, soft drinks are not appropriate for overweight persons. You would do better to slake your thirst with water or juice, and leave sodas for a treat. Unfortunately, he is an alcoholic who actively drinks. Lymphoma causes few early symptoms.