Apparently it can be a little dangerous to exercise too soon after waking up as the blood in your body thickens while you are asleep. This can provide unnecessary strain on the heart. Statistically, most heart attacks occur in the early morning. If you were to ask most professional sports coaches, I think that they would tell you that the days of athletes getting up at the crack of dawn to run 6 miles before breakfast with a log on their back are over, and nowadays merely the stuff of Rocky movies. If you need waking up in the morning, a slightly cold shower is probably a better way. The best time of day to exercise probably depends on when you wake up, but between 2pm to 6pm is likely to be the best time for most people. As regards eating, it's good to have had some food the day you exercise but it is probably wise to wait a couple of hours after eating a meal before you exercise. This is because you may feel sluggish or uncomfortable if your body is still digesting and you try to devote extra energy to your muscles. However, the horror stories of people eating, swimming immediately afterwards, getting cramp and nearly drowning are greatly exaggerated and it is doubtful that this has ever happened. The human body just isn't that inefficient. Some form of energy packed nutrition such as a Mars Bar, Banana or glucose tablets are OK to take a few minutes before exercise, or even during exercise if the activity allows it (for example the break between games in tennis). Remember though, if you are taking part in a weight loss programme, chocolate may not be the most beneficial of foods!