Water hydrates your body and keeps you going.
The body can only relax for 45 minutes before it starts to fatigue. I suggest standing up about every 30 minutes and doing 15 jumping jacks.
If you drink or eat foods that are high in sugar or caffeine, you will eventually. I suppose it's fine in moderation, but too often, you'll crash and become tired.
The face and neck do not stay alert forvery long, because theydon't move as much as
other parts of the body. Splashing cold water on your face or neck will "wake them up" and make you more alert. It is only temporary, so when you begin to feel tired again, splash the water again.
Your ears are full of pressure points. If you rub a pressure point, it makes blood pump faster, thus, giving you energy. Rub your ears for about a minute everywhere. You'll begin to feel instant energy.