Studies have shown that even a 10-minute workout can improve your fitness level and keep your exercise momentum going while you are traveling. Ideally, a 10-minute "express workout" won't be the limit of your travel exercise, but you can use the opportunity of doing several 10-minute workouts instead of one longer workout to target trouble spots.

For example, a 10-minute ab workout that includes 2 minutes of 5 different exercises will help trim your waistline and build strength in your core muscles. The walking lunge with rotation is a popular element of a 10-minute ab workout.

Here's how to do it:

• Stand with your feet hip width apart. Hold a small dumbbell with both hands and extend your arms in front of you.
  
• Step your right foot forward and bend your knees to a 90-degree angle to come into a lunge. At the same time, rotate your torso to the right, keeping your arms straight and parallel to the floor while you hold the dumbbell.
  
• Exhale and return to a standing position, then repeat to the other side. Alternate for 2 minutes, moving smoothly and with control.

Other elements of a 10-minute ab workout include a seated torso rotation or alternate side torso twists while lying on the floor.

For a 10-minute cardio workout when there is no gym handy, jump rope in your hotel room, or lace up your shoes and run up and down the hallway. Find the staircase and run up and down a few flights of stairs to increase the intensity and replicate a hill workout.

Running may be the best travel exercise because all you need are your shoes and workout clothes. Also, going for a run gives you a chance to see more of wherever you might be (assuming that it is safe) -- this way you can use your workout time for sightseeing.

Keep these points in mind to enjoy your runs when you are staying in a new location:

• Use your watch. If you don't have a map or mileage guide, don't stress about it. Invest in a nice -- but not too nice -- stopwatch to take traveling (so you're not traumatized if it gets, lost, damaged, or stolen). Run in one direction for 10-20 minutes, then turn around and go back to your starting point and go 10-20 minutes in the opposite direction. Repeat as needed based on approximately how far you want to run. If your usual training pace is 9 minutes per mile, run for a total of 45 minutes and you have done your 5-mile run.

• Ask the staff. Be sure to talk to the hotel concierge (if there is one) or some other member of the staff. Some hotels have running maps with a variety of distances to suit many runners' needs. Others may be able to point you towards a nearby park or trail.
  
• Use the treadmill. Hotel treadmills vary in quality, but they can be the better choice if you are in an area where it isn't safe to run outside, or if you have to squeeze in a run early in the morning or late at night. Caveat: Some hotels charge extra to use a fitness center, so be prepared for this expense.

When you're packing for a trip, pack your workout gear first, so you don't forget it. Fortunately, most high-tech, performance workout wear is fairly thin, light, and easy to pack. Make sure you have moisture-wicking items (including sports bras) that can easily be rinsed out in the hotel bathroom sink and dried quickly. If you are going where it's colder, or if the weather conditions will be variable, pack light layers rather than a bulky jacket and you can accommodate a range of temperatures for a travel workout. For example, you can layer two shirts and a light windbreaker instead of a heavier jacket.

If you are stuck at a location with bad weather and you don't want to buy a jacket, buy a large plastic garbage bag (or convince the hotel staff to give you one). It sounds weird, but a large plastic bag is a great disposable windbreaker on a cold, rainy, windy day if you are otherwise under-dressed.

Another travel gear tip: Pick your clothes with pockets. If you don't have any workout items with built-in zippered pockets, it's worth getting at least one pair of shorts or top with this feature. The pockets may be designed for energy bars or gels, but they are perfect for holding those card-style hotel room keys and possibly a small map.

You can also make your travel workout clothes do double duty. Don't want to bother with a swimsuit? You can get in the pool in shorts and a sports bra, or (for men) wear your swimsuit as shorts for running, biking, or using indoor fitness equipment.

Travel and exercise involves more than enjoying a workout at your vacation or business destination. These days, small planes and scrunched seats can leave you feeling tight, especially if you fly after a tough competition or workout.

Keep these travel fitness tips in mind to make your journey more comfortable:

• Stay hydrated. Planes are dry. If you don't want the hassle of buying water at the airport, be sure to ask for water, not soda or alcohol, when the beverage cart comes around. And get some water as soon as possible after you land.

• Stand up. It won't make your neighbors happy, but stand up and walk to the back of the plane at least once during a flight that lasts more than 2 hours. You'll get the blood flowing to your legs and feet, and you can do a few simple shoulder and neck stretches, too.

• Wear sensible shoes. If you want to get in a little exercise by walking around the airport because your flight has been delayed (again!) you'll be more likely to do so in sneakers, or at least comfortable walking shoes. Flip flops are easy to take off at the security check point, but you might not want to spend your half hour wait walking around the airport in them. When you travel, you may be walking more than usual on a variety of surfaces, while managing heavier loads than you usually carry on any given day, so having supportive shoes will prevent injury and put you in the mood to take the opportunity for that airport stroll.

Combining travel and exercise can be a challenge if you are traveling for business to a location not of your choosing that might not be fitness-friendly. Although you can't pack your entire gym into your suitcase, you can tote a few simple items that will help you get a decent workout when you are on the road.

Consider bringing these calorie-burning basics for a travel workout:

Jump rope: The jump rope gives you cardio benefits in the comfort of your room, and if you buy a thin, plastic speed rope (like the kind many boxers use) it takes up no space.

Resistance band: You may have used these bands of plastic tubing or seen them at your gym, and if you travel often, it's a good investment. Even the very fit can get a resistance workout by doing arm and leg exercises with one of these bands.

Swimsuit: If you are staying at a hotel with a pool, take advantage of it. Even if you aren't much of a swimmer, doing laps with whatever stroke works for you will give you a cardio workout and relieve some of those travel knots. If the hotel facility has kickboards or foam belts, you can do pool running, too. Or bring your own (if your suitcase space permits).

Shoes: Pack your shoes in your carry-on bag. Even if the rest of your luggage gets lost, workout shoes are the hardest thing to replace. Travel with your shoes and any other specialized gear (such as orthotics or a knee or ankle brace) in your carry-on and you'll have no excuse for not getting in a workout.

If you are lucky enough to visit Sydney, Australia, you can still maintain your fitness program with help from the variety of Sydney personal trainers and gyms to be found in this city.

You can find "mobile" personal trainers who will come to you and put you through a workout, or you can link up with a fitness group while you are visiting. Find a local running club or ask at your hotel about renting a bike and you'll have a new way to explore the city and get your workout in. You can combine exercise with sightseeing by taking a cycling tour of the historic part of the city known as The Rocks, or take a walking tour of the extensive Sydney Opera House.

In addition, check out one the many gyms and fitness centers in Sydney. Your home gym may even have a branch there. But keep in mind that the gym machines and settings are probably different than what you're used to at home, so be sure to ask the Sydney personal trainers or staff to show you how to adjust the weights or bikes as needed.

However you work in your Australian workout, keep these travel exercise tips in mind when you are far from home:

• Pack a small first aid kit with band aids, antibiotic cream, alcohol wipes, and hand sanitizer.
• Bring copies of any prescriptions that you may need, and bring extra medications if you are visiting for more than a week or two.
• Check your vaccinations.
• Check the climate: Winter in the United States is summer in Sydney. January is usually pleasantly warm, while February can get uncomfortably hot, so plan accordingly when packing your workout gear.

When visiting London, you will lose plenty of the pounds in your wallet, but you also have ample opportunities to trim a few pounds from your frame -- or at least avoid gaining any extra pounds from British food and drink. London personal trainers and gyms can help you stay fit during your visit. You can find information online about London personal trainers and gyms, and contact them before you depart to find one that fits your location and schedule.

Are you a member of a YMCA? Even if you aren't, check out the London personal trainers and classes at the Central YMCA club at 112 Great Russell Street in London. As foreign gyms go, this one is a treat, offering more than 100 exercise classes each week that range from cardio to yoga to water aerobics. Speaking of water, you need not miss your swimming workouts while in London. The Central YMCA also boats a 25-meter lap pool.

But if you want to get fit outside of the gym, take a run through London's Hyde Park, or get a leisurely workout by taking one of the city's many walking tours, with themes such as history, the Beatles, and Jack the Ripper.

Many athletes like to combine a vacation and a competition, and the United Kingdom hosts many sports events, including marathons, triathlons, and cycling events.

For example, the London Marathon in April hosts some of the world's best runners on a course that takes you all around the city. Caveat: The number of entries accepted from outside the U.K. are limited, so sign up early. If you want a British marathon that has fewer crowds but more hills, the Edinburgh Marathon in May is becoming increasingly popular.