How to Increase Your Running Stamina
To increase your running stamina, try cross training, such as lifting weights, which will teach your body to use oxygen more efficiently. You can also try intervals on a stationary bike. Just increase the tension on the bike until it's difficult to pedal, stand up, and push hard for half a minute. Then release the tension as you sit down on the bike and catch your breath. These intervals will help you when running hills. Additionally, swimming is a great way to build upper body strength, which many runners lack.
Use interval training. There are several benefits to interval training that will help you get the most out of your runs, and increase your stamina. Improve cardiovascular capacity. Endurance running can take wind out of you. By using the interval training, you'll increase your anaerobic capacity (oxygen-depleting). And when you combine this with aerobic capacity (oxygen-building with easy runs and long runs), these will end up making you faster. Burning calories. Bursts of energy (the high-intensity part of interval training) will increase the amount of calories you burn. This is true even for relatively short bursts. It adds interest to your running routine. It may seem a small thing, but boredom with your normal running routine can make it much harder to stay motivated. Perform steady intervals. This is the easiest way to incorporate interval training. You simply alternate equal periods of high and low-intensity running. Start with a ten to fifteen minute warm-up. Start with a rapid walk followed by a slow jog, picking up speed at the end of the warm-up to break into a full run. This will make sure your body is properly warmed-up before you begin the intense speed work If you are first starting out doing intervals, you need to train your body to get used to the hard intervals. Run at high speed for one minute followed by two minutes of slow running or walking. Repeat these intervals six to eight times. Do this for several weeks until you feel comfortable with the rest. Then lower your recovery/rest time by 30 seconds until you are running 50/50 burst (such as one minute burst followed by one minute rest). Make sure you and your body are ready to increase the intensity of the faster pace intervals and reduce your rest/recovery period before you reduce the rest/recovery time. End with a fifteen to twenty-five minute cool-down. Ease from a run to a light jog, and then gradually slow to a walk towards the end of the cool-down period. Use pyramid interval training. Pyramid intervals start with short bursts of high intensity and then build up so that the longest period of high-intensity training is in the middle of your workout. Then, you gradually pull back to the shorter burst of intensity before completing your cool down. This is somewhat more complex than steady intervals, and you may want to use a stopwatch to maintain your times. Warm up for ten to fifteen minutes. As described above, begin with a rapid walk followed by a light jog, picking up speed at the end of the warm up so that you are running at high intensity at the end of the warm up period. Run for 30 seconds at high intensity. Then, run at low intensity for one minute. Continue as follows: 45 seconds high, one-minute, fifteen-seconds low. 60 seconds high, one-minute, thirty-seconds low. 90 seconds high, two minutes low. 60 seconds high, one-minute, thirty-seconds low. 45 seconds high, one-minute, fifteen-seconds low. 50 seconds high, one minute low. Finish up with a twenty-minute to thirty-minute cool down, ending at a comfortable walk. NOTE--> When you start out any interval training program, you need to make sure your body is adjusted and ready to start it. Doing too much too soon can lead to injuries. Just like when you are building up your mileage, you don't just build up. You gradually build up. IF you are pointing to a specific race, you do longer intervals with longer rest several months before the race. As the race approaches, you increase the intensity and shorten the recovery. Do variable intervals. If you play sports like tennis in addition to running, you know that speed and stamina requirements vary according to the conditions of the game. Variable intervals help you to mix up short and long high-intensity intervals in an unpredictable pattern, which more closely mimics the irregular bursts of speed that are part of typical playing conditions. Warm up for ten to fifteen minutes of easy running. Mix it up. Run for two minutes at high intensity and then jog slowly for two-minutes, thirty-seconds. Run at top speed for 30 seconds and then jog for 45 seconds. Mix up your intervals at random. Just make sure that you rest for longer periods after longer high-intensity intervals than you do for short bursts. When starting out, keep your rest periods slightly longer until your body is ready to shorten the rest intervals. Cool down for fifteen to twenty-five minutes. Use the interval setting on a treadmill. When you run intervals on a treadmill, the machine mixes up both the speed and the incline, presenting you with new and unpredictable challenges. Just make sure to warm up and cool down afterward if these periods aren't built into the interval training program. Add weight training to your running. Weight training increases your running economy, which means that you use oxygen more efficiently during your run. Try doing free weights, machines or other strength training exercises three times per week. Do high-powered bike intervals. Pedaling on a high-tension exercise bike setting works your leg muscles even more than running uphill, without the impact on your joints. While you pedal on an exercise bike, gradually increase the tension until you can barely move the wheel. Stand up and do intervals of pedaling as fast as you can. Rest and lower the tension between intervals. For example: Stand and pedal at high tension for 30 seconds. Then sit, lower the tension and pedal more slowly for 1 minute. Keep alternating between standing and pedaling at high intensity and sitting and pedaling at low intensity for 1 minute. You can also perform pyramid intervals of 30, then 45, then 60, then 90 seconds. Then, bring it down by doing 60, 45 and then 30 second intervals. Be sure to do the lower-intensity seated pedaling between the high-intensity intervals. Sign up for a spinning class—the instructor will guide the class through a prepared set of pedaling exercises that will dramatically increase your stamina.  Swim some laps. You can either swim as a break after a hard workout or simply include some swimming to change up your routine. Swimming has the added advantage of working your upper body muscles, which are typically underdeveloped in runners. Take a long run on the weekends. If you're used to running 2 miles (3.2 km) per day during the week, then take a weekend run for 4 miles (6.4 km). Run slower and longer. For example, run at 60 percent of your capacity for longer distances. The long run is meant to help build stamina, and it is not a race. Make sure to take easy days before and after these runs. Try  plyometrics. Plyometrics exercises like jumping rope and skipping drills can help to improve your running mechanics by lessening the amount of time that your feet stay on the ground. Increase the pace at the end of your runs. For the last quarter of your workout, run as quickly as you can before cooling down. This exercise will help you to counteract late-race fatigue. Run on changing terrain. Whether you're running outdoors or on a treadmill, change your incline frequently to give your cardio workout a boost.. Change your diet. Cut out refined carbs and eat more lean protein and vegetables. Also, eat smaller, more frequent meals. Set a schedule. It will help to stick with your regimen if you make a schedule, and stick to it. It will help you accomplish your goal of increasing your stamina, and will also give you an opportunity to gather metrics: do you maintain a steady pace? Are you able to run longer or faster (or both), or have you reached a plateau? Here is a sample schedule that will help you develop both endurance and speed: Day 1 - Steady Intervals. Warm up for 15-20 minutes, then run at high speed for one minute followed by one-minute, fifteen-seconds of slow running or walking. Repeat these intervals six to eight times. Maintain a steady time for each phase (using a stopwatch), and then cool down 20-30 minutes, gradually slowing to a walk. Day 2 - Easy run day (only 2–5 miles (3.2–8.0 km), depending on you and your running experience). Day 3 -Pyramid intervals. Warm up for ten to fifteen minutes, and then run a pyramid interval set, as described above. Run at a comfortable pace for 15 minutes, then do a variable interval set. Finish up with a twenty to twenty-five minute cool down, ending at a comfortable walk. Day 4 - Easy run (2–5 miles (3.2–8.0 km),depending on you and your running experience). Day 5 - Easy run (2–5 miles (3.2–8.0 km),depending on you and your running experience). This might seem like a lot of rest, but then you did run pretty hard on Day 3. And given you are running long on Day 6, it would be best to be well rested when you run long. Day 6 - Long run. Start slowly and run at an easy, conversational pace for 40 to 90 minutes. It is helpful to have a friend or family who is willing to run with you, or at least follow along on a bike. Day 7 - Rest day (2–5 miles (3.2–8.0 km), depending on you and your running experience. Every 8th week, take the day off.) Mix it up a little. Push yourself once every three weeks or so with this technique: Find a local track or flat surface of about ⁄ 4 mile (0.4 km) (400 meters) to run on. Avoid streets, as they are too curved; the curb foot will be noticeably lower than the street-side foot. Stretch with dynamic stretches ( not static ) and do a light warm up (e.g. 25 push ups or jog). Do a ⁄ 4 mile (0.4 km) sprint followed by a ⁄ 4 mile (0.4 km) jog. Do the sprint and jog routine for at least 2 miles (3.2 km). Exceed your reach. Once you've reached your limits of duration, make note of the time and the location of your run. Keep that as your minimum distance/duration, and try to beat that number. As you improve, raise your baseline. Do a cool down. After every run, you do not just want to stop running. Walk the run off till your heart rate is moderate. Then stretch. Make a commitment. Do not quit your regimen, do not tell yourself you'll do it tomorrow, do not tell yourself you're too tired, and do not tell yourself you're too busy. Run in the morning to get it over with. 
Use interval training. Perform steady intervals. Use pyramid interval training. Do variable intervals. Use the interval setting on a treadmill. Add weight training to your running. Do high-powered bike intervals.  Swim some laps. Take a long run on the weekends. Run slower and longer. Try  plyometrics. Increase the pace at the end of your runs. Run on changing terrain. Change your diet. Set a schedule. Mix it up a little. Make a commitment. 