I've started an exercise program of vigorous walking for about 30 minutes followed by 10–15 minutes on a rowing machine. I get thirsty during my workout, but I've been told not to drink any fluid during this time because it is best to drink a thirst-quencher that replaces minerals and fluids after exercising. Do you agree with this?
Definitely not! You should drink water any time you take a break during your workout. For your particular program, it would be best to drink water either between walking and rowing, or before you start your walk. Don’t wait until you get thirsty. If you can tell you’re losing water, replace it.
Even if you don’t perspire during exercise, which you probably do, you will lose fluid through breathing. Your blood volume is directly related to your water volume and intake.
If you get dehydrated, your blood volume will be lower. Blood is necessary to move oxygen and nutrients to the cells and flush out waste products and CO2. Lowered blood volume will cause the heart to pump faster and harder, placing an unnecessary strain on your heart.
I would also recommend staying away from athletic drinks to replenish fluids and minerals. Most of them are loaded with sugar, giving you a quick blood sugar rise only to be followed by a drop with fatigue. Instead, drink water or diluted apple juice or orange juice (50 percent juice, 50 percent water). After cooling down from exercising, eat a piece of fruit.