Both running and lifting weights give you benefits for fitness and health. You can run in the morning and lift later on if that suits your lifestyle and fitness goals. Running increases your cardiovascular endurance, while lifting weights develops your muscular strength and increases your lean muscle mass. If you are primarily a weightlifter, you may run to lose weight or decrease your body fat percentage. A runner often lifts weights to build muscle strength but may not be interested in developing large muscles.
Running in the morning and lifting later in the day gives you a complete workout in one day. If you can only train three days a week, this schedule allows you to complete both a cardiovascular and a weight training workout on a consistent basis. Regular cardiovascular exercise such as running helps you maintain a healthy weight, reduces your blood pressure and resting heart rate. The lean muscle mass you build through weight training can help your metabolism, develop strong back and core muscles and improve your posture.
If you run long distances or run fast intervals, the exertion required can leave you too fatigued to effectively lift weights on the same days that you run. To combine running and weightlifting on the same day, you should use the weightlifting days as easy running days. Reduce your normal mileage substantially, or run at a slower, easy pace. Your same-day weightlifting workout should be shorter than you would perform if you only lifted weights on that day, to avoid injury from improper form or muscle fatigue. Over time, your body will adapt to the twice-daily workout schedule, and you will be able to run farther and lift heavier weights.
Run first thing in the morning, after you have a light breakfast. Set a goal of running for 30 to 45 minutes to give yourself a good workout that burns calories but does not overly fatigue your muscles. Spending the rest of the day at your normal activities such as office or house work, school responsibilities or social functions allows your muscles to have a chance to recover before your weightlifting session.
Schedule your weight training session either directly before dinner or about an hour after dinner. Perform upper-body and core training on the days that you run and lower-body work on the days that you do not run, if possible. Your leg muscles will likely be slightly fatigued after your morning run, and you may find that you are unable to use heavy weights while performing squats, leg presses or that you become fatigued during lunges. Use lighter weights for lower-body work if you do perform lower-body exercises on your running days.