Women's Health: Rhythm Method

Feel like your energy level has more dips than the prepared-food section at Trader Joe's? Here's why: One minute you're blasting through your to-do list, and the next, you can hardly doodle a checkmark. Sound familiar? It should -- it's Biology 101. Every day, you experience dips and surges in vigor, compliments of circadian rhythms. "They're the biological clocks in the brain, governed by the 24-hour cycle of light and darkness," says Martin Moore-Ede, M.D., Ph.D., CEO of Circadian Technologies, a research and consulting firm. These cycles control everything from hormone changes and temperature to blood pressure and your ability to think clearly. Take a closer look at your daily energy fluctuations, then click on a time period to find out how you can skip the lows and ride the highs. 6:30 a.m. to 7:00 a.m. Sleep Inertia: During the first 30 minutes you're awake, thinking and reaction times are substantially impaired. Levels of the hormone cortisol, which kicks in when you're stressed, are lowest around midnight and build up from there. This boost clears the cobwebs, and grogginess subsides. 7:00 a.m. to 12:00 p.m. Morning Hustle: Between breakfast and lunch, your sense of alertness peaks. "Brain chemicals like norepinephrine, glutamate, and dopamine rise in the morning to promote awakeness," says Chris Fahey, Ph.D., a physician at Northwestern University's Circadian Rhythms and Sleep Research Lab in Chicago. Take advantage and tackle tasks that require critical thinking, such as closing a deal. Save routine activities like filing paperwork and Googling your ex for the slump to follow. 12:00 p.m. to 5:00 p.m. Siesta Period: The Spanish weren't just onto something with sangria and paella; naptime demands an "Olé!" too. At some point during the afternoon, you could experience more drag than a Key West Halloween party -- typically a spell that lasts up to 2 hours. According to Fahey, this urge to nod off may be an evolutionary trait passed down from our ancestors: Getting out of the sun and into the shade prevented heat stroke during the hottest hours of the day. 5:00 p.m. to 8:00 p.m. Sunset Spike: Wahoo! This is your biggest energy peak since the A.M. "There's a surge of energy and alertness when we come to the early evening," Dr. Moore-Ede says. It's also the trickiest time to nap, no matter how hard you try. 8:00 p.m. to 6:30 a.m. Transition Time: Approaching sleep, we go through 90-minute cycles of feeling alert and drowsy, alert and drowsy. (It's no coincidence that sleep cycles follow the same schedule.) Dips and surges that occur before bed help your body transition from being awake to falling asleep, Dr. Moore-Ede says. Chemicals like melatonin flood your body as you snooze. Source