Are you feeling tired around 2pm and "needing" some caffeine?? I would bet you are most likely dehydrated. Most people do not drink enough water to support their organ functions properly, thus we start to feel fatigue by mid-afternoon. Our bodies are 60-70% water. When we become dehydrated, we don't function as well, our immune systems run down (which brings on sickness), and we just don't have the energy to do much anything. Caffeine is a diuretic so if we consume too much caffeine (more than 200mg - a cup of brewed coffee is 83mg) we risk becoming dehydrated also.
A few simple tests to see if you are hydrated enough:
1. If your urine is yellow, you are dehydrated.
2. If you are fatigued by 2pm, you are dehydrated.
3. If you have waited until you are thirsty before you grab up some water, you are dehydrated.
Our bodies need >80ounces of water a day. And the more physically active you are OR out in the heat, you will need much much more!