“Water needs can vary from person to person — and no one person will need the same amount of fluid from one day to the next,” the Virginia scientists wrote in the American College of Sports Medicine’s Health and Fitness Journal.

The typical American consumes about one liter — a little over four cups — of drinking water a day. But people like me who engage in quasi-vigorous physical activity daily need more, and those who exercise strenuously for more than an hour a day need even more than that, perhaps supplemented by a sports drink containing the electrolytes sodium and potassium (but avoid those with more than a pinch of sugar). Keep in mind that skimping on your liquid intake or relying on sugary drinks can take a toll on your physical performance.

If you’re planning to engage in strenuous exercise or do physical work outdoors on a hot day, it’s best to start hydrating the day before. Check the color of your urine; the paler it is, the better. Also continue to drink water or other fluids throughout your activity and for hours afterward.

A critical factor in remaining well hydrated is not to rely on thirst to remind you to drink but rather to be proactive by consuming enough liquid before, during and after meals and physical activity. The longstanding advice to drink eight glasses of water a day was something I (among many others) was never able to achieve. I’m happy to say that experts have since modified that rule. Current thinking calls for getting about 70 percent of daily water needs from liquids (including coffee and tea, by the way, though not alcohol) and the rest from solid foods.

The authors of “Quench” suggest two dozen fruits and vegetables that are especially hydrating, ranging from cucumbers with 96.7 percent water to grapes with 81.5 percent water. Surely you can find many you would enjoy in a list that includes lettuce, tomatoes, cauliflower, spinach, broccoli, carrots, peppers, watermelon, strawberries, pineapple, blueberries, apples and pears.

Even chia seeds, an ancient so-called superfood said to sustain the ultrarunning prowess of the Tarahumara Indians of Mexico, can be a force against dehydration; they absorb 30 times their weight in water and can provide the body with slow-release hydration, especially during long bouts of physical activity in high heat and humidity.

Naturally packaged plant water hydrates more efficiently than plain drinking water, the “Quench” authors maintain, because it’s already purified, is packed with soluble nutrients and gradually supplies the body with water.