The Honest Pros And Cons Of Running Twice A Day

You are an avid runner, and you are more than likely wanting to push your body beyond its current limits, but you want to know whether it is a good idea or not to go as far as training twice per day. Is it risky? Does it give any benefits? What are the pros and cons of one running twice per day?

Studies suggest that running twice a day offers benefits not only for long-distance athletes or professionals but also for the average running enthusiast. Doubling up on your training will result in greater fat-burning and aid endurance; however, you are at a greater risk of potential injury.

Running doubles, the term for running twice a day, is something that pretty much all elite and professional athletes will do–or, if not running twice a day, they will add a second form of cardiovascular exercise to improve their overall fitness, endurance, aerobic capabilities, and to lengthen the time before they fatigue.

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Now, what if you aren’t a pro runner, but you simply want to better your current distance or time and get to the next level in your running? Well, we have the scoop on what you need to know about training twice a day.

Should You Run Twice A Day?

This will depend on what level of a runner you currently are what your goals are. Also, factors like time availability and your general recovery time will come into play; however, there are tremendous benefits that you could get from doing this sort of training.

Keep in mind, though, that you do still need to give your body time to recover, so try to leave at least five hours between sessions–even better, six to eight. 

One thing that you could do to start your twice-a-day training is to split your run into two sessions, or you could do a longer and more taxing run in the morning and then when the afternoon or evening comes around, go for a more relaxed, slow-paced jog.

This will increase the amount of human growth hormone, which you produce more of during your second workout in a single day (source), although the benefits of HGH are not 100% clear. Another advantage that you will experience is the doubling of your resting metabolic rate, which spikes after each session, and this too will help with weight loss.

What Happens If You Run Twice A Day?

When you are running twice per day, you are shortening the time frame between workouts, which will ultimately help train your body to recover much faster. However, it may be a struggle initially as your body may not be used to the additional exertion.

One area that we have mentioned is that twice-daily running will help with fat loss as your body will be using mitochondria more effectively. (source) There’s conflicting evidence of whether your your body makes more mitochondria from twice-a-day exercise,, but either way your body will learn to use its mitochondria more effectively–this will result in warding off muscle fatigue.

Mitochondria are the powerhouses of our cells and are responsible for generating the majority of the chemical energy required to activate and power the biochemical reactions that take place within the cells of the body.

Additional to these benefits, your enzyme activity is increased when you choose to train more than once per day.

Now, what is enzyme activity, and why is it relevant? Enzymes, particularly those found in our bodies, help ramp up the speed of chemical reactions, which aid in our survival. They are vital to many tasks within our bodies, like the construction of muscles, digestion of food, and the destruction of wastes and toxins.

Is Running Twice A Day Healthy?

Running twice a day can actually have some negative health side effects depending on the circumstances.

If you intend to start training twice per day, then it is a good idea to start gradually and build your way up to your desired level of performance.

Starting slow helps because at first, running twice a day will be a slight shock to your body, which will have to adapt to your new training plan: you may experience more frequent muscle spasms, and your joints will also potentially feel stiffer from the more frequent contact with the blacktop or sidewalk. (If you’re lucky enough to live near a trail, you won’t experience that same joint pain. See our article here of trail running vs. road running)

One idea to make this easier is to split your existing training into two sessions to help get your body used to two sessions a day. Additionally, you can go for an easier and shorter run in your second session, where you do not worry too much about pace (at least at first).

Over time, two training sessions a day will help increase your overall mileage run per week and surprisingly, actually help with recovery as your second workout will aid in increasing the blood sent to your muscles.

In the beginning, it may well be challenging to push yourself to double your training, but you will soon reach a point where the second run will push your body to expand its capacity and performance. If you find on certain days that you cannot bear to head out onto the road or track again, there are other alternatives that will help to reap similar results, such as cycling and jumping on an elliptical.

However, if your body is not ready for this level of stress, you can hurt yourself. Your body has a limit, and depending on how hard your exercise sessions are, you may run into injury, if not simply exhaustion.

The Pros Of Running Twice A Day

Now we finally come to the crux of it all; why even consider running twice a day? Let’s jump into some pros and cons. Rest assured that if you listen to your body and work with a good training plan–or even enlist the help of a trainer–you will likely end up reaping the rewards as opposed to the potential negative aspects.

Bodily Function Changes

When you double up on your training, you will be burning more glycogen, and your body will need to adapt to this new state. You will be also be burning more significant amounts of fat, and your body will become more efficient at using your glycogen stores.

You will experience quicker recovery rates, and over time you will notice that your threshold for fatigue will be extended. Because you are doing aerobic exercise more frequently, your lungs and heart will also become stronger, increasing your overall fitness level.

Faster Recovery

When you are training twice per day, you shouldn’t push yourself as hard in the second session, but rather treat it as a means of therapy for your body. The less demanding runs will aid in increasing blood flow to your muscles, giving your cells the oxygen they want to recover. If you can’t do a big run in the later session, try to do an exercise, such as sprinting or shuttle runs which will get your heart rate up and help with your overall fitness and endurance.


Adding Endurance

Running twice per day, especially if you are doing a long run in the morning and a shorter one in the evening (or doing an equally long but less demanding session later), will add to your overall miles. This will help your body go further and for more extended periods, and if you are training for a marathon, it is precisely what you are looking for.

In this study–they found evidence to suggest that training while your body is in a low-glycogen state (less energy, so, in other words, your second workout in a day), that your body will adapt more quickly to your physical training.

The Cons Of Running Twice A Day

Injuries and Recovery

When you are training twice per day, your legs and particularly your joints in your legs and hips experience the jarring impact of the road or track underfoot. This is why you need to be sure to warm up properly before both sessions, and it is advisable to invest in a good pair of running shoes that offer the best possible support.

If you feel like your body is taking strain from your increased training, consider returning to running once per day and supplementing with other aerobic exercises like swimming or cycling. Also, be sure to leave sufficient time between your training sessions to allow your body to recover and be mindful of overtraining.

Difficult to Not Overtrain

As we’ve learned, pushing your body past its supposed limits can do great things for your physical performance, but it’s difficult to not cross the boundaries into overtraining (source). Striking the balance between exercising but not overtraining (negatively) requires your own experimentation.

Time and Food Commitments

If you are serious about kicking things up a notch, (which, if you’re reading this, you probably are) you will undoubtedly have already realized that this will take a lot of time and dedication on your part.

However, it is not just the time spent running that you need to factor in; you also have to consider prepping, travel time, and dressing before, then your post-run recovery, the fact that you’ll need to get ample sleep, and you will most likely need to be eating more frequently during the day, as your body is going to be burning more fuel.

Potential Negative Endurance

This point contradicts what we have mentioned before–but it applies to beginner or intermediate runners who are not used to running more than 50 miles per week. If you are newer to running and your distances are short, it would be more advisable to increase your distance and speed over a single session than splitting your running into two sessions.

Excessive Weight Loss

One thing is for sure: running is excellent for losing weight and keeping it off if you watch your calorie intake. This, for many people, would be a benefit; however, when you become very serious about running, you need to be aware that your metabolism is going to be in overdrive and your body will need sufficient fuel. If you are not careful, you could end up with an unhealthy weight, which is counterproductive to your goal, which is to be fit and well.  

How Much Should I Be Running?

If you’re serious about distance training, the ballpark figure is that you should be running at least fifty miles per week: this should increase over time and will also obviously be dependent on your level of running and your personal goals.

An optimal training split is if you could be running at least 60-90 minutes in your first session and then roughly 30-45 minutes in the second session.

These are not hard and fast rules to abide by. If you aren’t there yet, then this is something to aim for, and if you are already training more than this, then all there is to do is to increase your time spent running or trying to run the same distance, but faster.

When Should You Be Considering Adding Doubles To Your Workout?

We now know what happens when we run doubles and are aware of the advantages and disadvantages. We need to consider when including doubles into our training plan would be beneficial–and it may not be wise to do this on a permanent basis. Usually, the reason why we consider running doubles at all is in preparation for a race or event.

Also, as said before, doing doubles may hinder beginners as their bodies are just not ready to make that extra leap into pushing that much harder. So, if you have been running for less than three to five years, perhaps this needs some reconsidering. However, if you are a more seasoned runner, this type of training should definitely improve your all-round performance.

One other thing to keep in mind is that even though the goal is to push yourself to reach the next level in your running journey, just like any other type of sport you need to take rest days and have days where your training is less taxing so that your body has the necessary time to recover and to be protected against burnout and potential injury. 

For a basic guide to how much you should be running for specific events and whether you should consider going for the doubles style of training, below is a table for your reference. Note that the miles per week will be done between the two separate sessions.

EventMileage Run Per week
5 Miles55 – 60 Miles
10 Miles65 – 70 Miles
Half Marathon (13.1 Miles)70 – 75 Miles
Full Marathon (26. 2 Miles)75 – 80 Miles


So the verdict is in. We have firmly established that doubles are a viable option to increase and improve your overall training, as long as you pace yourself and increase training incrementally so that your body can adapt. If you are just looking to lose weight and get fitter, this is also not a bad idea; just be sure not to over-train and pace yourself.

You will be burning more calories, and your metabolism will increase, so you will have to take your nutrition just as seriously as your running. Be sure to eat enough of the right foods to aid in replenishing your body and to help with recovery between runs.

You also need to take rest into account and make sure that enough time elapses between the first and second run of your day. Leave an absolute minimum of five hours between them and, if possible, try to expand the interim to between seven and eight hours.

We have helped you examine the pros and cons of doing doubles, and now the rest is up to you, so put a strategy together and lace up for your new way of training. If you have found that you would prefer to stick to exercising once per day, consider adding a different type of training to the mix, to provide your body that extra edge when it comes to race day.

One last thing I wanted to mention is that exercise science is conflicted on whether you should exercise twice in a day with a rest day or once daily for a week. (see this study for some conflicting evidence) Ultimately, you have to find what works for your body and your schedule. It’s a great idea to experiment with different methods to see what works best for you.


Peter is a software developer who loves to take every opportunity to go outside that he can get. Peter grew up going on long backpacking excursions with his family every Summer and now enjoys staying at the beautiful Texas State Parks and swimming in the amazing Texas Rivers.

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