First off, it is not clear if you are running on an indoor or outdoor track. For the sake of this answer, let us assume you run outdoors when you do your track runs.

Physically, there could be some slight differences between how your body expends energy running on a track versus a treadmill.

• the treadmill belt offers some help by pulling your feet back underneath your body, so you’re potentially exerting less energy to move your feet and legs than if you weren’t on a treadmill.

• When you run indoors on a treadmill, you don’t have to overcome wind resistance. the lack of wind means you will spend less energy running four miles on a treadmill than you will running four miles outdoors.

Nevertheless, it might depend on how fast you are running. For the averageperson, running 5 to 9 miles per hour (mph) will lead to little difference.

Some studies say outdoor running expends up to 5% more calories; if you run faster than 9 mph, running outdoors could utilize up to 10% more calories because you’re working harder against wind resistance. Other studies say there’s no difference.

One study demonstrated the way to balance energy use between indoor and outdoor running is to set the treadmill at an incline (or grade) of 1 percent.

• Running indoors maintains or offers stable elements. Runners not only avoid wind, but also other potential natural elements, such as cold air, rain, or sand (if you run on a beach), which demand additional energy.

• Running on a treadmill vs. pavement (the composition of the track surface you run on is unclear) provides a softer surface, making it a little easier for your joints.

People with knee pain or soreness might opt for a treadmill vs. the road outside for this reason.

These explanations offer the argument that physically you must be able to run farther on a treadmill than on an outdoor track because a treadmill requires less energy.

Many individuals , though, do find running on a treadmill incredibly boring. Boredom lets someone think about how tired he / she is, perhaps more rapidly than when he / she were not bored. Being distracted might help him/her run for a longer duration.

Sports and exercise psychologists often refer to the “distraction hypothesis” as an explanation for the stress/anxiety reducing effects of exercise. Running, in this case, gives someone a time-out from daily stressors or worries, and authorizes him/her to be distracted.

A number of individuals enjoy running on a treadmill because they are able to watch television, listen to music, or just zone out and run.

Others prefer running outdoors because they are distracted by the scenery, other individuals , the weather, varying terrain, and/or avoiding traffic. Perhaps getting outside onto a track gives you time outdoors to breathe fresh air and enjoy the sunshine.

Maybe you are the sort of person who feels energized by being outdoors, for instance, and that feeling and energy increase your endurance.

The next time you run on a treadmill, when possible, position yourself in front of a TV or listen to your favorite music to see when you are able to run for a longer period of time.

It is also unclear whether or not you are running at the same pace on the track versus the treadmill. When you have not already done so, use a stopwatch to measure your running speed. Maybe you are running at a faster pace on the treadmill, and that’s why you are tiring faster.

Other factors go into how a person feels when the person runs, including the food(s) the person has eaten, how well the person has slept, and/or whether or not the person is hydrated.

Every day is a different day for our bodies. But if someone is a consistent runner, and has fairly consistent lifestyle behaviors, it might be that their enjoyment of the outdoors is what fuels their running.