As runners, we don’t like to feel bogged down when we run. But have you ever been in the middle of a run, and suddenly your legs feel abnormally weighed down? It happens to many of us.
This is known as running with heavy legs, and it can occur for no apparent reason. It’s unpleasant, but if you know what it is and how it happens, you can better plan your fitness schedule to avoid it.
Let’s look at heavy legs and how you can stop it from happening.
What Are Heavy Legs?
Heavy legs, better known as heavy leg syndrome, is a frustrating experience that happens to almost all runners at some point.
It feels as though someone has strapped weights to your shoes, as your legs become heavier and weaker with every step you take. You’ll find it difficult to pick up the pace and feel like you’re dragging a 50-pound sandbag behind you!
Unfortunately, heavy legs can happen any time, and it’s likely to be accompanied by a drop in performance as your runs feel harder. You may even find that you’re not using energy efficiently as your running form is off, making you feel tired faster than normal.
Your legs may also feel achy, crampy, and stiff, almost putting you off running for good!
The good news is that the condition is not permanent. It may just be that you need to make some easy adjustments to make your legs feel better, especially on longer runs.
Reasons for Heavy Legs
Here are several possible reasons that can contribute to you experiencing the heavy feeling in your legs.
We often push ourselves, especially as we achieve new PBs or see how our bodies are transforming. But this can lead to you putting too much physical stress on your body, which results in overtraining and may cause heavy legs.
While running has great benefits for the body, your bones and muscles strengthen at a slower rate than your cardio fitness increases. You may feel like you can push on, but your body isn’t quite there yet.
Even seasoned runners can experience heavy legs, especially during their most intense training weeks leading up to a race.
Overtraining can result from your training plan progressing too rapidly or due to the high volume of mileage you’re doing. Both of these can leave your legs feeling weak and heavy as a result.
If your legs are feeling heavy, you may want to check if you have any of the following signs of overtraining:
- Lower performance than usual
- Perceived effort seems higher—your runs feel harder than they used to
- Muscle fatigue and tiredness—tired legs while running, but you’re not out of breath
- Resting heart rate has increased
- Increased risk of injuries—strains, sprains, or leg fractures
Skipping Warm-Up and Cool Down
It can be tempting to skip your warm-up and start your run at a slower pace before you increase the intensity. But you could be doing yourself and your long-term gains more harm than good.
Warm-ups gently prepare your body for the rigorous demands of your run by increasing blood flow to the muscles. As a result, the temperature of your muscles increases. This improves muscle elasticity, allowing them to stretch and contract smoothly.
When you head straight into your run, the muscles will be tight and less flexible. This will increase your risk of injury and could leave you running with heavy legs.
Wrapping up your run with a cool-down is equally important, as this helps to prevent blood from pooling in the lower extremities. It also keeps the blood flowing, preventing your blood pressure from dropping rapidly and making you feel dizzy.
Add some post-run stretches into your cool-down, as this is a great way to start clearing the lactic acid from your body. You can also include foam rolling, which will help reduce muscle stiffness and pain.
By adding a proper warm-up and cool-down to your running routine, you’ll find that your legs will feel limber and lighter both after and during your runs.
If you want to improve your running efficiency, endurance, and running form, then strength training can help. But your timing, intensity, and volume can leave your legs fatigued, especially when DOMS sets in.
It’s important to note that DOMS can last for up to two days after the workout, and this can cause that heavy feeling in the legs when your muscles begin to fatigue during a run.
You need to ensure that the strength training aligns with your running training plan and needs. It’s best to modify the intensity and volume of the strength workouts so that you gain muscle, correct muscle imbalances, and maintain your muscle mass.
Do your strength training on your active rest day before your rest day. This allows your muscles plenty of time to rest and recover, making it less likely that your legs will be affected during your runs.
You may also want to consider doing an easy or recovery run for 1 or 2 days after an intense strength training session. While you won’t be breaking any PBs, it will help loosen up the muscles and reduce DOMS.
Dehydration can sneak up on you, and you may find yourself feeling fatigued. This can result in tired legs, which may make you feel like you’re running with heavy legs.
If you don’t replace the fluids you’ve lost, your muscles will begin cramping, and your blood will become thicker. Your heart will then have to work harder to pump the blood throughout your body.
Aside from fatigue, you may also experience the following:
- Dizziness or feeling like you could pass out
- Persistent headache
- Dry mouth, lips, and eyes
- Difficulty breathing
- Decreased urination
- Dark yellow urine with a strong odor
Staying sufficiently hydrated is incredibly important during runs, but so is replacing electrolytes, especially on a long run.
If your body doesn’t have enough glycogen stored in the muscles when you run, your legs won’t have the fuel they need to perform. This can cause your legs to feel heavy as you run, causing you to feel sluggish overall.
As part of a balanced diet, your body needs complex carbohydrates, which are converted to glycogen that’s then stored in the muscle. Your muscles use glycogen as an energy source to propel you forward during exercising.
If your glycogen levels are low, then your body won’t store as much glycogen in your muscles. Once your stores are depleted, it’s harder for your body to create energy while you’re running, leaving you feeling like you have “dead legs”.
You’ll usually experience heavy legs on long, intense runs, so having the right nutrition with you on your run is important.
It’s also better to experiment with different chews and energy gels while training. This will help you to find the best energy gels that work for you.
An iron deficiency develops over time and plays an important role in our energy-making process as we run. Iron forms part of the protein called hemoglobin in the red blood cells that helps carry oxygen to the muscles.
When you have an iron deficiency, your body won’t be able to supply oxygen to your muscles when you run.
You’ll then notice that your performance drops, you feel fatigued, and your legs will feel heavy. You may also experience an increased heart rate or shortness of breath.
It’s important to note that an iron deficiency does share common symptoms with overtraining. You should see a doctor if you experience overall fatigue and heavy legs during running with any of the following symptoms:
- Chest pain
- Headache, dizziness, or lightheadedness
- Difficulty concentrating
- Pica—where you crave non-food items like dirt, chalk, clay, or starch
- Restless leg syndrome
Poor Blood Circulation
Poor blood circulation could be the underlying reason for you experiencing heavy legs while running. In most cases, it’s a condition known as chronic venous insufficiency.
When you move your legs, the muscles contract, which helps to return blood to the heart. The veins have tiny valves to help prevent blood from flowing back down.
But if you have chronic venous insufficiency, these valves don’t function properly and allow oxygen-depleted blood to flow back down into your legs.
This can often lead to swollen and heavy legs. Your body also uses oxygen as an energy source; as you run, your heart will work harder to get oxygen-rich blood to the muscles to cope with the high demand.
If you have poor circulation, you may not get enough oxygen-rich blood to the muscles. This means that there’s not enough oxygen to convert into energy, which can leave you running with heavy legs.
Wearing shoes that aren’t quite right for you can cause your legs to feel heavy. For example, if you have recently switched to wearing stability shoes for overpronation, they tend to be heavier and stiffer than neutral shoes and can make you feel weighed down.
But that’s not the only time your shoes can make your legs feel heavy. If you don’t have enough support in your shoes, your feet may be under high amounts of stress every time they hit the ground. This can increase fatigue, which can bring on the feeling of heavy legs.
You will need to find a shoe that offers the best balance between supporting your foot and being lightweight. That being said, you may still experience heavy legs for different reasons, even if you wear the perfect shoes.
Poor Running Form
If you’re new to running, then you may struggle with good running form. With that being said, any runner can have poor form, especially if you have weaker hips or poor core strength.
Poor running form places your body under excessive stress; it makes you slower, which causes you to fatigue faster and makes your legs feel heavy.
Running with good form will help prevent muscle imbalances and ensure your body uses energy efficiently. This prevents you from fatiguing too quickly, which can often lead to injuries, and greatly reduces your risk of running with heavy legs.
Not Getting Enough Sleep
You may feel like you have enough energy to power through the day and run on just a few hours of sleep. But not getting good quality sleep or enough hours of rest can result in tired legs.
While you should be getting between 7 and 9 hours of sleep, research shows that one-third of Americans get less than 6 hours of sleep per night.
When you go to sleep, your body goes through a restorative process. During this time, it repairs soft tissue damage, gets your hormones back to healthy levels, and supports the immune system.
If you’re not getting enough sleep, you’ll find that you won’t have enough energy to go about your daily activities or to exercise and effectively recover. This will increase your risk of sport-related injuries and make you more likely to experience heavy legs.
What to Do When It Happens?
When you feel your legs getting heavy during your run, the best thing to do is slow down. You need to listen to your body, so when your legs get tired, slow your rhythm and adjust your pace to accommodate them.
This will give your muscles a bit of a break as you’re taking stress off of them, and it will also reduce your risk of accidentally tripping or falling due to your tired legs.
You don’t have to slow down so much that you have to walk. Make sure to control your pace as you go downhill and try to land your feet more gently than usual, so the impact is less.
You may want to stop for a few moments and stretch before you keep jogging. This can help you to ease up any stiffness in the legs while also helping to increase circulation, which can make the heavy feeling feel better. Lifting your feet higher while running can also help to increase blood flow.
Don’t fall into the trap of trying to stick to your pace if your legs aren’t up for it. Whatever the reason behind your heavy legs, listen to your body and exercise accordingly. It will prevent you from feeling worse or overtraining.
Tips to Prevent Heavy Legs
But with that being said, there’s no specific way to fix heavy legs during your run. It depends on the reason behind it, but even if you fuel up on the run when you feel your legs getting heavy, it won’t be absorbed and converted in time to take the problem away.
The best way to handle heavy legs is to prepare yourself before you run. Thoughtful preparation will not only help you to maximize your training, but it should help you to get around any problems before you even get on the road.
Here are our top tips to prevent heavy legs while you run. If you prepare yourself with these tips, you can expect to suffer from heavy legs less often.
Increasing your training intensity, duration, or frequency too quickly can lead to overtraining, which makes it more likely for you to develop heavy legs.
Make sure to increase whatever you’re doing by 10 percent a week at the most. For example, if you ran 10 miles last week, only increase by 1 mile the following week. If you ran for one hour last week, only increase by 6 minutes this week, and so on.
This will give your body time to adapt to new and progressive levels of training, so it doesn’t struggle to keep up with you.
Keep Speed Training to 20%
Eighty percent of your training should be a mixture of easy runs, recovery runs, and moderately intense training. Only 20 percent should be high-intensity speedwork training.
You should also have enough of a break in between your speedwork sessions so your muscles can recover. This will prevent overtraining and potential injury.
You should be staying well-hydrated even when you’re not running. From morning until evening, you should be drinking throughout the day to ensure that your body has enough water.
Of course, staying hydrated during your run is important too. But paying attention to your hydration when you aren’t running can give you a boost.
Careful Strength Training
You need to avoid doing intense training sessions on the same day or the day before a run. When your leg muscles are fatigued, it puts you more at risk of developing heavy legs during your run.
Some runners prefer to work hard on strength training during the off-season. This will help you focus on building muscle while not training hard for your running.
You can lift heavy without worrying about upcoming races, although you may still experience heavy legs in off-season training runs.
Once the running season begins again and you’re actively training for races, you should cut down to one or two weekly strength training sessions.
Research shows that this is enough to maintain the muscle you built during the off-season while keeping your legs as fresh as possible for races.
Working on your running form can help to take the strain off your legs and help improve your performance.
You should aim to shorten your stride and ensure that your front foot doesn’t land out in front of your body but rather underneath your hips. This is likely to help you create a shorter, more efficient stride.
Try to keep your body upright and face forward instead of looking down. Relax your shoulders and arms as you swing them. Your arms shouldn’t cross in front of your body.
Your core should also be engaged as you run; this will help you to keep good posture and maintain your running form.
The better your form, the longer it will take your legs to fatigue. This can help to prevent that heavy leg feeling.
Increase Carb and Protein Intake
Just like staying hydrated throughout the day, you should pay attention to your diet. Lack of carbohydrates can contribute to your body not being able to utilize energy effectively, so increasing your carbohydrate intake can ensure that your body’s glycogen stores are always ready to convert to energy.
You should eat healthy carbs throughout your day, but you can eat more just before your run. Having a carbohydrate-heavy meal three to four hours before your run—or the night before if you run in the morning—can prime your glycogen stores.
Increasing your protein intake can help your muscles to recover properly, as protein stimulates muscle growth. Red meat is also rich in iron, which can be beneficial in preventing heavy legs, although you should eat more white meat than red meat.
Maintain a Healthy Weight
By maintaining a healthy diet, you should more easily maintain a healthy weight. This takes the strain off of your legs, and they won’t fatigue as quickly.
One key to maintaining weight is eating fresh, whole foods and avoiding processed foods. These typically contain a high-calorie count but low nutrition.
You should prioritize rest if you want to reduce the chance of heavy legs. Aim for 7 to 9 hours of sleep per night.
To help you, you should have a bedtime routine that maximizes your chance of a good rest. Avoid blue light from the phone or TV for at least 30 minutes before bed. Also, avoid taking caffeine within 4 hours of bedtime.
If you can’t get enough sleep at night, you can try adding in a short nap during the day. Make sure the room is dark and quiet and at a comfortable temperature.
Plan your Run Nutrition
Taking an energy gel during your run can help you boost energy, but if you’re already experiencing heavy legs, it won’t help much.
The key is to avoid getting to that point in the first place. You can do so by planning your race/training run nutrition beforehand.
If your run is going to be short, you should eat a carbohydrate-rich meal 30 minutes before. If you’re going for a longer run, then you should take nutrition—energy gels, energy bars, and electrolytes—with you.
It’s wise to keep yourself fueled before you feel like you need to be fueled. This will ensure that energy is always readily available to your body, and your legs shouldn’t become so fatigued that you experience heavy legs.
You should do the same with hydration. Adding an electrolyte tablet to your water bottle will ensure that you don’t lose important nutrients, which may contribute to cramps and heaviness in your legs.
Warm-Up and Cool Down
Warm up with some dynamic stretches and five to 10 minutes of moderate-pace walking or light jogging. This will help to loosen up your muscles, increase circulation, and prime them for running.
After your run, cool down by jogging at an easy pace for five to 10 minutes. You can also do some light stretching at the end of your run.