Sleep is an essential body process that ensures that our waking selves are in good condition physically, mentally, and emotionally. Get too little or too much sleep, and you'll function poorly, feel depressed and fatigued, having slower response times, be more prone to injuries, and lower your body's immune response, among other things. Here's another way to look at it- national traffic safety experts have reported that more fatal accidents are caused by drivers who are asleep at the wheel than are intoxicated.
The amount of sleep any given person needs is individual, and depends on their personal body chemistry and balance, the stressors they face in their life and the physical challenges they face. Between seven and ten hours is considered normal. If you wake up tired, changes are, you need more or less sleep. A lack of sleep threatens your health from all corners.
Exercise is a good way to both tire your body so you'll sleep easily at night and to ensure that you feel wakeful and energized during the day. A good night's sleep will ensure that your body can properly repair itself after a workout and that you'll have energy for your next workout. You should wake up feeling well rested and energized each morning.