• Skipping your workout to save energy actually works against you. Regular exercise boosts strength and endurance, helps make your cardiovascular system run more efficiently, and delivers oxygen and nutrients to your tissues.
  • Being even slightly dehydrated takes a toll on energy levels, says. Dehydration causes a reduction in blood volume, which makes the blood thicker. This requires your heart to pump less efficiently, reducing the speed at which oxygen and nutrients reach your muscles and organs.
  • When you wake up in the morning, you need to refuel with breakfast. Skip it, and you'll feel sluggish.
  • Constant blood sugar spikes followed by sharp drops cause fatigue over the course of the day. Keep blood sugar steady by having a lean protein along with a whole grain at every meal.
  • Starting your morning with caffeine is no big deal—but using caffeine improperly can seriously disrupt your sleep-wake cycle. Consuming caffeine even six hours before bed affects sleep, so cut yourself off by mid-afternoon.
  • A glass of wine sounds like a good way to unwind before falling asleep, but it can easily backfire. Alcohol creates a rebound effect as it's metabolized, which creates an abrupt surge in the adrenaline system, he says. This is why you're more likely to wake up in the middle of the night after you've been drinking.