The actual benefits to running on a treadmill start immediately. Any exercise you can do on a treadmill on a regular basis will do you good. However, for the recognized health benefits the CDC recommends jogging for 75 minutes per week. Jogging or faster is classed as vigorous physical activity.
The 75 minutes per week can be divided into 10 minute segments. So you could do 10 minutes every day with one being slightly longer at 15 minutes. However it's good to have a rest day so 15 minutes a day 5 times a week works. However you want to divide it up as long as it's convenient for when you can fit it into your schedule.
The benefits are reducing your risk of many diseases, cancers and heart problems. It strengthens your bones and muscles. It improves your mental health and mood. You will generally live longer. If you can double that activity time so that is 150 minutes per week you get even greater health benefits the CDC says. However any you can fit into your time is a good thing.
Running for weight loss
Running is the best accompaniment to losing weight. If you watch what you eat and do some strength training then weight loss will be your natural side effect. If you're new to running then you can do a walk run routine to get used to exercising for longer periods. This walk/run plan for beginners will help you get started.
To get good consistent weight loss and reach your target weight you need to be running for 20 minutes and be doing that 3 or more times per week. The reason is for the calorie burn. It takes 3,500 calories to burn 1 pound of fat. So while it might take some time to lose weight, you will get there if you keep at it. When you're at your desired weight keep running to maintain it and improve your overall health. Here are some useful pages for weight loss:
Training for a race
Sometimes you've got to train for a race on a treadmill. Whether it's the outside weather or some other reason. We would always recommend you do one run outside per week if that's where the race is taking place. Training depends on how far the race is and how long it would take you to run that far.
If you have a race of 5k which is 3.1 miles and you run 10 minutes per mile (6 mph) then it will take you around 31 minutes to complete the course. You should then build up your running time on the treadmill to exceed that. Try running to 40 minutes the week before then when you encounter the race you'll find it easier as you've run further than that distance already.
You may want to do some speed work in your training runs. These are designed for treadmill running and will enable you to run faster in your normal runs. If your race has hilly parts of the course you can also repeat that on a treadmill. Try using the incline to replicate those hills. Here are some training routines for different races:
Whatever you're running for there is time investment required. Exercising is not something you can dip in and out of. Especially if it's for one of the reasons above. Whether it's for your health, for weight loss or for a race you have quite a commitment when it comes to it. That's why a treadmill is so convenient. Where ever you stop on a treadmill you're always at the beginning instead of miles from home.
If you're running for weight loss and health benefits then we recommend you combine the 2. By doing what we recommend you run for health benefits you will get all the weight loss benefits as well. That is jogging or faster for 75 minutes a week. You can do that all in 3 times a week or spread it out to 7 days a week it's up to you.