The Best Time of Day to Do Just About Anything

Take a Nap

1 p.m. to 2:30 p.m.

Doctors used to think afternoon sleepiness was the result of a big lunch. "But we've found that in the early afternoon there's a dip in body temperature, which causes sleepiness," says Michael Smolensky, a professor of environmental physiology at the University of Texas School of Public Health at Houston and author of The Body Clock Guide to Better Health: How to Use Your Body's Natural Clock to Fight Illness and Achieve Maximum Health ($19, amazon.com). Just as a similar decrease encourages you to shut down at bedtime, this midday dip can make you crave a siesta. An ideal nap, he says, should last 15 to 20 minutes. More than 30 and you may end up with sleep inertia―and feel even more groggy when you wake up. Richard Schwab, M.D., codirector of the University of Pennsylvania Penn Sleep Center, in Philadelphia, says that early afternoon is indeed when your circadian rhythms (the pattern of physical and mental changes we each repeat every 24 hours) are "more likely to want your body to sleep." But Schwab insists that if we weren't all sleep-deprived, we wouldn't even need naps.

Read (and Retain) Information

8 a.m. or 10 p.m.

If you're going over notes for today's presentation or memorizing the names of your child's classmates' parents before the school open house tonight, do it early in the morning, when your immediate recall is highest. For longer retention (the book club meets in three weeks, but this weekend's your only chance to finish The Good Nanny), evening is better. "This is just the way the brain is organized," says Smolensky. "Memory depends on nucleic acids, and those show circadian rhythms." In other words, your brain doesn't store information with the same efficiency all day; there are peaks and valleys. "College students often unknowingly take advantage of the dual circadian rhythm by staying up late studying, then doing a quick review the morning of the exam," says Smolensky.

Go to the Doctor

8 a.m. to 9 a.m., or 1 p.m. to 2 p.m.

You'll spend less time in the waiting room if you book the first appointment of the morning or the first after lunch, says Patricia Carroll, R.N., author of What Nurses Know and Doctors Don't Have Time to Tell You ($15, amazon.com): "Doctors start fresh in the morning and catch up when the office is 'closed' for lunch." Many lab tests require fasting, so a morning appointment will help you avoid being hungry half the day. If you're seeing a doctor who performs surgery (orthopedist, gynecologist), ask that your appointment not follow her operating time―a recipe for serious delays, says Carroll. Pediatricians' and family-practice offices can get mobbed when work and school let out (5 p.m. to 7 p.m.). And if you leave with a prescription to be filled, try to visit the pharmacy before 3 p.m. on weekdays, when it's least busy―"which also reduces the risk of error," says Carroll.

Pop a Multivitamin

Breakfast time

Taking your supplements with a meal is important because "vitamins are components of food, and whether water soluble or fat soluble, they are absorbed better with food," says Shari Lieberman, Ph.D., a New York City and Hillsboro Beach, Florida, nutrition scientist and coauthor of The Real Vitamin & Mineral Book ($17, amazon.com). "Also, as with many other pills, you're more likely to get queasy if you take multivitamins on an empty stomach. Breakfast is the meal of choice. Because most people have it at home (whereas lunch and dinner are often eaten elsewhere), making the morning meal your time for vitamin-popping will help you stick with the habit. Another reason dinnertime may not be a good option, Lieberman adds, is that certain nutrients, including vitamin B, may keep you awake.

Walk the Dog

8 p.m. to 9 p.m.

To you, walking the dog may be about exercise. To him, it's all about the social life, explains Jean Donaldson, author of Dogs Are From Neptune ($15, amazon.com) and director of the San Francisco SPCA's dog-training academy. Owners have more time to stroll in the evening and to let their pets linger over exciting smells and sounds missed on the morning-rush walk. Evening walks also let him avoid midday overheating. He can make himself comfortable before bedtime, says David Reinecke, the founder of Los Angeles-based Dog Remedy behavioral training.

Do Your Cardio Workout

5 p.m. to 6 p.m.

"For increasing fitness, decreasing the chance of injury, and improving sleep, the best time to exercise is late afternoon or early evening," says Matthew Edlund, M.D., author of The Body Clock Advantage: Finding Your Best Time of Day to Succeed In: Love, Work, Play, Exercise ($15, amazon.com) and head of the Center for Circadian Medicine, in Sarasota, Florida. At these times, he says, your lungs use oxygen more efficiently, you're more coordinated, and your muscles are warmed up, so you're less likely to suffer a sprain or strain. Finish exercising at least three hours before bed so that when your head hits the pillow the extra adrenaline will no longer be pumping through your bloodstream (and other factors that keep you awake will also have subsided). Bonus: "If you're all wound up at the end of the day, exercise may be a great stress reliever," notes Shirley Archer of the Stanford Health Improvement Program, in Palo Alto, California.

Ask for a Raise

5 p.m.

"The key is finding a moment when your boss is not rushed and has time to truly listen," and that's most likely to be the end of the day, says Lynn Ellis, a career coach in Austin, Texas, who has worked with employees and bosses at global companies like Unilever. "That's when I'm getting ready for the next day or looking ahead to the next week, and I'm in a good mood because I'm going home soon," says Amy Holloway, a vice president at Angelou Economics, in Austin. And you'll have a biological edge then, since, as Edlund, points out, your elevated body temperature makes you more alert in the late afternoon. But asking for a raise is not an exact science. Ellis advises tracking your boss's daily habits to find the ideal, low-key time for him or her. And, in the end, if you're at your best in the morning, just go for it.

Return Merchandise

10 a.m.

Arrive with your what-was-I-thinking sweater within the first hour a store is open. Workforces are leaner these days, but “retailers still need enough staff to open up, so that may be when they have the best ratio of staff to customers,” says Edward Fox, director of Southern Methodist University’s JCPenney Center for Retail Excellence, in Dallas. It may also be the only time all day when staff are at assigned posts, “so you can usually get someone to help,” notes former fashion stylist Linda Arroz, who spent years returning things she didn’t end up using for movies and TV shows. Fox adds that “the most experienced people get the best hours, so they will be working the day shift.” Finally, consider customer flow. “A city store may be busier during weekday lunch hours, a suburban store on weekend afternoons,” says Target spokesperson Lena Michaud.

Go to the Post Office

7:30 a.m. to 10 a.m.

The U.S. Postal Service may have more than 700,000 employees, yet there never seems to be enough of them when you're waiting in line to mail a birthday present. Your best chance, according to USPS spokesperson Monica Suraci: Find out when your post office opens (generally between 7 a.m. and 9 a.m.) and arrive a half hour or so later. You'll hit a midmorning lull, missing the rush of early birds lined up at the door (as well as distracted window personnel chatting with carriers sorting the day's mail). Heavy traffic is more likely at lunch, at the end of the workday, and just before closing, so those are times to avoid. Suraci's tip: Look for USPS "contract stations," which offer services in locations like supermarkets and drugstores, and for machines in some post-office lobbies that weigh and stamp packages most any time.

Get a Haircut

8 a.m. to 9 a.m.

Booking the first appointment of the day will help you ease into the shampoo bowl on time. That’s because no latecomers will have thrown off the schedule, says Serena Chreky, co-owner of the Andre Chreky salon, in Washington, D.C. Saturday mornings (after busy workweeks) are usually the least frantic, says Allen Ruiz of the Jackson Ruiz Salon Spa, in Austin. However, some salons fill up then with bridal parties, Chreky cautions, so ask when you book. An early appointment may also get you the best cut. “Stress levels are at their lowest,” says Michelle Breyer, cofounder of NaturallyCurly.com, which deals with salons nationwide. “Even if you’re only the third or fourth client of the day, your stylist may not look at your hair with the same enthusiasm.” For the best service, Breyer and Ruiz both suggest asking your stylist, “What’s your favorite time of day to do hair?”

The Best Time of Day to Fly

"Although U.S. Department of Transportation statistics show that flights taking off between 6 a.m. and 7 a.m. have the best on-time record, those numbers are sometimes misleading," says Rally Caparas, an Atlanta-based air-traffic controller and a Travelocity "Eye on the Sky" correspondent for CNN. "On time" refers to when the plane pushes back from the gate. You can wait on the tarmac for an hour because of weather problems, which cause the vast majority of delays.

"Scheduling arrivals and departures between 11 a.m. and 1 p.m. local time," Caparas says, "will help you avoid most delay-causing weather patterns. This will also help you avoid airport rush hours, "which mostly coincide with workday rush hours," says Robert Baron, president of the Aviation Consulting Group, in Fort Lauderdale.

For best results, check for regional weather patterns and schedule accordingly. "For example, for the West Coast, fly in or out after noon Pacific Standard Time, when marine-level fog has dissipated," says Caparas. For southeastern and Gulf Coast hops, steer clear of the thunderstorms that kick up around 3 p.m. "Airline schedules are based on perfect weather conditions," he says. "You're more likely to be punctual if you follow Mother Nature's schedule."

Clean the House

4 p.m.

You're more likely to whistle while you window wash (and not kick over the bucket) if you do it in the late afternoon. That's when hand-eye coordination is at its peak and mood levels are high, says Smolensky. If anyone in the house has allergies or asthma, avoid insomnia-hour and morning cleaning sprees (nasal-allergy symptoms are most severe between 6 a.m. and noon, asthma attacks more likely between midnight and 6 a.m.), and finish well before that person walks in the door. "It takes about an hour for allergens and dust to settle after you clean," says Martha White, M.D., director of research at the Institute for Asthma and Allergy, in Wheaton, Maryland.