I have started exercising a month ago. I do a two hour workout starting with 20 Min of cardio and then weights. I sweat a lot, and by a lot I mean wetting the floor kind of sweat. I weigh 600-700 grams less after a workout. I keep drinking water during this, a guy from the gym told me that I should mix something like Glucose or anything else to keep the strength up for the whole session. I also feel like I am totally exhausted after the first half hour, Is that a good Idea to do ? cause I think glucose have sugar and sugar is bad. right ?
Not all sugars are the same. Glucose is a monosaccharide, and is easily utilized by nearly all cells of the body for energy. Fructose, also a monosaccharide, is not: it is almost exclusively metabolized by the liver. Excess consumption of fructose causes a variety of problems that would not occur with glucose consumption.
Sucrose ("table sugar" or "cane sugar") is a disaccharide composed of a glucose and fructose molecule. Similarly, lactose (milk sugar) is a disaccharide. Polysaccharides are long-chain polymers consisting of monosaccharide units--these are found in various complex carbohydrates (e.g., starches and certain dietary fibers such as cellulose).
So, "sugar" and "carbohydrate" are very broad terms. If we say "glucose," that is a specific molecule whose biochemistry is distinct from other simple sugars. To say "sugar is bad" is a gross oversimplification. If we're talking about refined sugars that are added to processed foods, then yes, it's best to avoid these, especially fructose. But not only is glucose unavoidable in our diet, our own bodies synthesize glucose from non-carbohydrate foods, including fat (gluconeogenesis). In fact, this is how our bodies "burn fat."
The bottom line is that glucose is not harmful. Whether your body needs it during exercise is another question entirely, one that depends on the duration of physical exertion and the energy demands of your activities. If you're running a marathon, you would be ill-advised to not consume any kind of nutrition during the entire race. If you're just running a mile or two, your body has plenty of stored energy available to do that. Where that transition occurs also depends on the shape you're in.
600-700 grams of weight loss isn't anything to be concerned about; you can easily make it up after the workout. You could go with glucose, though you don't need to replace calories for that short of a workout.
If you want to replenish more water, I'd recommend something with electrolytes in it. That will allow you to absorb the water more quickly.
As a general rule, avoid sugar (glucose) at all times. Sugar is a bad thing for your health. There are better sources of carbohydrates. If your goal is to cut (loose fat) then the answer is NO. If you are an athlete and your goal is to improve muscle mass or endurance then sugar (and other simple cabs) have some place in your diet. But this last doses not seem to be the case for you.
The simple rule is this: Replenish the fluid you lose. It's worrying to see gymmers sipping on electral or glucose water when your body doesn't need the electrolytes or calories they contain. Drinking glucose water sends your blood glucose levels into a tizzy, pushing you towards a mild addiction to sugar. You need it only if you play an outdoor sport like cricket or football." Having small, quick gulps of water instead of sips is better since in the latter, fluid is likely to leave the stomach more rapidly.
The problem that high insulin caused by sugar consumption is good for anabolism (building glycogen), while exercise is all about catabolism (using up glycogen). So there is a contradiction here. I think, that you'd better to eat some starch rich food low in fibers, e.g. white bread, white rice and drink water instead of consuming sugar rich sport drinks. It does not increase the insulin level that much and it lasts a lot longer. From sugar I use to get a 5-10min energy boost, but after that it is a lot worse than it was before and I can't wait to reach the next drink (by running).