Most runners will agree: there’s nothing more frustrating than having heavy legs when running. It can seem that even when we diligently complete our training, our legs still feel heavy while running. After weeks or months of progress, “dead legs” can feel incredibly defeating.
Why do my legs feel heavy when running?
Whether you’re just getting started or have been training for months, heavy legs often seem to pop up out of nowhere. When things are going well, it can be difficult to pinpoint the reason that your legs are suddenly feeling heavy while running.
However, if your legs continue to feel heavy and tired when running, evaluating some of the most likely causes might help point you in the right direction.
Heavy legs can be caused by a variety of different factors when running. Sometimes the things we do before or after a run can contribute to the heavy feeling we experience in our legs. Other times, our fueling or lifestyle plays a role. And occasionally, dead legs can be caused by something more serious.
Potential Causes of Heavy Legs During a Run
- Overtraining
- Insufficient recovery
- Improper running form
- Lack of sleep
- Poor circulation
- Low iron levels
- Insufficient fueling and/or hydration
Most causes of heavy legs when running usually have something to do with your training. The quantity of miles and intensity of your workouts can sometimes contribute to that heaviness you feel during a run. If you are putting in too much mileage or intensity, your legs might feel heavy as a result.
Related: How Many Miles to Run? Finding Your Optimal Running Mileage
Another common reason for heavy, tired legs on the run is lack of recovery. Skipping out on the post-run stretches, easy runs or rest days is likely to add up over time. Many beginners might also find that poor or improper running form is causing them to experience dead legs.
If your training and recovery have been consistent, evaluate your sleep, hydration and fueling habits. Insufficient carbohydrates can quickly deplete your energy during a run and cause your legs to feel tired.
A few runners might find themselves battling more serious causes, such as poor circulation or low iron levels.
Regardless of the cause, when your legs feel heavy while running, making a few simple changes might be all it takes to regain momentum and energy during training.
How do you get rid of tired, heavy legs when running?
Whether you know the exact cause of your heavy legs or are merely speculating, most runners who are plagued with heavy leg syndrome are eager to learn how to get rid of it. Luckily, fixing heavy legs when running usually involves just a few simple changes.
7 Ways to Prevent Heavy Legs While Running
Prioritize post-run recovery
One of the most common causes of heavy legs during a run is lack of proper recovery during training. In addition to regular rest and easy days, recovering after a run is key to staying healthy.
Completing a few simple post-run stretches can help prevent excessive lactic acid buildup, flush out any toxins, and avoid any soreness that may lead to heavy legs.
>> Try these 15 post-run leg stretches!
Tweak your training plan
Another common reason that your legs feel heavy when running: overtraining. Overtraining looks different for every runner – one person might be able to easily tolerate 40 miles a week while another does best with 20.
The key to avoiding overtraining in all situations is to listen to your body and increase mileage or intensity gradually. If you are otherwise healthy and your legs continue to feel heavy while running, try slightly lowering your mileage or intensity during speed workouts until your legs no longer feel tired on the run.
Switch up your pre-run fuel
If training seems to be going well but you continue to have heavy legs when running, it might be due to insufficient carbohydrate intake. Another way to help prevent dead legs on the run is to ensure you are adequately fueling your runs and workouts.
Try consuming a carb-heavy meal or snack before your longer runs and hard workouts. Bagels, bananas, toast or pasta are all great choices.
Increase your water intake
Dehydration can be another cause of heavy legs on the run. Water plays a key role in the body’s recovery process, and a lack of sufficient intake may reduce your muscle’s capacity while running.
A general guideline is that you should aim to consume about half of your bodyweight in ounces of water each day. The more active you are, the more water your body requires.
Related: Running Hydration | How Much Water and When to Drink
Improve your running form
Heavy legs when running might be a sign that you have poor or improper running form. Improper foot strike, overstriding, a slow cadence, or poor posture could all cause your body to have to work harder to run. The more effort required to run, the more energy your body expends and the less likely it is to have recovered before your next run.
Take the time to evaluate your running form. Check in to your cadence – you should aim for a cadence of around 180 bpm. Evaluate your foot strike by looking for the wear on the bottoms of your shoes. Most runners benefit from a midfoot strike, which means that your soles should be the most worn near the ball of your foot.
Making a few simple tweaks to your running form will help your body run more efficiently, requiring less effort and therefore helping your legs to recover faster after each run.
Warm up and cool down
Sometimes, heavy legs are simply caused by a failure to warm up or cool down. When your muscles haven’t warmed up, they often feel heavy or tired while you’re running.
Dedicate 5 minutes to a pre-run warm up. Try these dynamic exercises to get your blood flowing and loosen your muscles before a run. When you return, take some time to complete a post-run routine to help your body cooldown and jumpstart recovery.
Check your iron levels
If you are training properly, emphasizing recovery, fueling well and staying hydrated but your legs still feel heavy while running, it might be time to check your iron levels.
Low iron levels can lead to a general heavy, achy or tired feeling throughout the body. If something feels off to you – getting your blood levels checked might be helpful.
Experiencing heavy legs when running can be very frustrating – but usually, all it takes is a few simple tweaks to your training to relieve dead legs.
Try these 7 fixes to see if they help you recover from heavy leg syndrome. Before you know it, you’ll be feeling fresh, strong and better than ever on the run.
