LEG CRAMPS | What Causes Leg Cramps in Runners?

Ever been jolted awake by a sharp, agonising leg cramp? Or felt your calf seize up mid-run, forcing you to stop in your tracks? If so, you’re not alone. Leg cramps in runners are a common and frustrating issue that can disrupt both your sleep, and your run.

These sudden, involuntary muscle contractions can strike anytime—during a workout, while at rest, or even in the middle of the night. While the exact causes aren’t always clear, factors like dehydration, mineral imbalances, and muscle fatigue are often to blame.

In this guide, Leg Cramps: What Causes Leg Cramps in Runners, we’ll explore the most common triggers, provide quick relief tips, and I’ll share strategies to prevent cramps so you can stay focused on your running goals.

Let’s dive in!

Quick Look.

Leg cramps can strike at the worst times—mid-run, during a race, or even while you’re fast asleep. While they’re usually harmless, they can be painful and disruptive, especially for runners. The good news? There are plenty of ways to manage, treat, and prevent them.

Here’s a quick overview of what we cover in this post to help keep those pesky cramps at bay:

• Common Causes of Leg Cramps: From dehydration and electrolyte imbalances to muscle fatigue and even poor sleep posture.
• Quick Relief Tips: Simple stretching, massage techniques, and when to use heat or cold therapy for fast relief.
• Prevention Strategies:
  • Staying hydrated and replenishing electrolytes during and after long runs.
  • Incorporating magnesium and potassium rich foods into your diet, or as supplements.
  • Building a daily stretching routine, including pre-run dynamic stretches.
  • Adjusting foot positioning at night to avoid cramps while sleeping.
• When to See a Doctor: How to recognise when cramps might be a sign of something more serious.
• Tried-and-True Tips from My Personal Experience: What’s worked for me over 20 years of running with (and learning to beat) leg cramps.

Whether you’re looking for quick fixes or long-term solutions, this guide has everything you need to manage and prevent leg cramps so you can stay focused on your running goals.

Curious about other issues that can affect runners? Check out my post ‘6 Most Common Running Injuries‘ here.

Let’s dive in!

What Are Leg Cramps? Understanding the Basics.

Leg cramps are a surprisingly common issue that can affect anyone—not just runners or athletes. These sudden, painful, and involuntary muscle contractions often catch people off guard and can happen at any time.

The most commonly affected muscles are the calves, but cramps can also occur in the feet, hamstrings, or quadriceps. The severity and duration of leg cramps can vary, lasting from a few seconds to several minutes, leaving the muscle sore or tender afterwards.

Leg cramps can strike during a run, disrupt your sleep at night, or even occur when you’re simply sitting or resting. While they typically seem random, they can be linked to specific triggers, such as overexertion, dehydration, or even prolonged inactivity in certain positions.

Though they are generally harmless, leg cramps can significantly impact your comfort and performance—especially for runners—making it essential to understand their causes and how to prevent them.

This is an issue I’m all too familiar with, having dealt with leg cramps throughout much of my running life of over two decades. Over time, I’ve learned how to manage and, for the most part, prevent them. Much of what I share in this article comes from personal experience and research into this problem. While I’m now largely free of leg cramps, staying that way requires ongoing awareness and management to keep them from coming back.

Let’s take a look at what causes these painful cramps.

Why Do Leg Cramps in Runners Happen? Exploring the Common Causes.

Scientists have yet to pinpoint a single definitive cause for muscle cramps, as they can stem from a variety of factors. However, several common triggers have been identified, and in many cases, cramps result from a combination of these. Being aware of these potential causes is the first step toward managing and preventing them.

Dehydration and Muscle Fatigue: A Common Culprit.

Dehydration and muscle fatigue often go hand in hand as significant contributors to leg cramps. While studies haven’t definitively linked dehydration to cramps, the combination of fluid loss and tired muscles can disrupt normal muscle function.

When muscles are fatigued, they are more prone to painful cramps, particularly during or after a run.

Ensuring proper hydration before, during, and after exercise can help maintain muscle condition and reduce the risk of cramping.

Electrolyte Imbalances: The Role of Magnesium, Potassium, and Sodium

Electrolytes are critical for smooth muscle contractions, and imbalances in key minerals like magnesium, potassium, and sodium can contribute to leg cramps.

Magnesium in particular is essential for regulating muscle function, while potassium helps muscles contract and relax efficiently. Sodium, which is lost through sweat during exercise, also plays a key role in maintaining the body’s fluid balance. A deficiency in any of these electrolytes, particularly during or after a long run, can increase the likelihood of cramping.

Replenishing these minerals through diet, supplements, or electrolyte drinks is crucial for runners, especially during long-distance training.

TIP: In my experience, any long-distance training run—over 25k, for example—can trigger calf muscle cramps if I don’t bring along an electrolyte drink to replenish the electrolytes lost through sweating, especially in warm weather. I’m also careful to consume an electrolyte drink after a long run to boost recovery, and prevent cramping.

Nighttime Muscle Tightening: Why It Strikes During Sleep.

Nighttime leg cramps are a common issue, and not just with athletes, with calf muscles being the most frequent form of cramping.

One key cause is foot positioning during sleep. When the foot is pointed downward (plantar flexion), as it often is due to tucked bedding or heavy blankets, the calf muscles are shortened, making them more susceptible to spasms.

To minimise the risk, try using lighter bedding, keeping sheets untucked, or sleeping with your feet slightly elevated or hanging off the edge of the mattress. Using a different sleeping position, such as on your side, may also help if you are suffering cramps regularly.

Overuse and Standing for Long Periods.

Prolonged standing or overuse of muscles during intense activity can lead to cramping.

Jobs or situations that require long periods of standing in one place can reduce blood flow to the legs and can lead to muscle stiffness. Similarly, overusing muscles during a strenuous run or high-intensity workout can cause fatigue, leaving the muscles more prone to cramping.

Incorporating rest periods, proper dynamic (not static) stretching, and pacing during exercise can help mitigate these triggers.

Given the complex and often seemingly random nature of muscle cramps, their exact cause is often difficult to pinpoint, and they may even result from a combination of these factors.

TIP: Note down any instances of cramping in your running journal, including details like the distance, intensity, weather conditions, hydration, nutrition on that day, or any other possible trigger. Over time, you may identify a pattern that points to a possible cause.

How to Treat Leg Cramps: Quick Relief Tips.

Experiencing a leg cramp can be sudden, unexpected, and often intensely painful, leaving you feeling helpless as your muscle tightens involuntarily.

Whether it strikes during a run, at night in bed, or even at rest, the discomfort can linger long after the cramp subsides. Fortunately, there are several effective techniques that can provide quick relief, helping you relax the muscle, ease the pain, and recover faster.

By knowing how to respond when a cramp strikes, you can minimise its impact and lessen its severity.

Stretching for Immediate Relief.

When a cramp strikes, gently stretching the affected muscle can alleviate discomfort. Try the following:

• For calf muscle cramps, try to straighten your leg and flex your foot upward, pulling your toes toward your shin.
• If a cramp strikes at night, getting out of bed and walking around can often help alleviate the discomfort. Personally, this is the type of cramp I experience most often, and I’ve found that walking while gently flexing or stretching the muscle is highly effective. This combination can help minimise the cramp or stop it entirely, allowing the muscle to relax and the pain to subside.
• Performing light stretching exercises before bed can help reduce the frequency of nighttime cramps. If you frequently experience cramps during the night, establishing a consistent stretching routine before bedtime might make a significant difference.

Before we move on from using stretching as a method to relieve leg cramps in runners, let’s take a closer look at some effective stretches for different muscle groups. Try these options to keep your muscles flexible as well as treat, prevent or minimise leg cramps in the future.

Calf Stretches:

Stand facing a wall with your feet approximately 40-50cms away from the wall and your palms against it at face level for support. Move one foot forward, positioning your toes close to the wall and with your knee bent, extend the other leg straight back, keep both heels flat on the ground.

Now lean forward gently until you feel a stretch in the calf muscle of your extended leg. Push your body back with your hands and arms to relax the stretch, then move back into the stretch in a controlled and fluid motion, being careful not to over-stretch. Perform this in and out motion for 30 seconds, then switch legs. You can repeat this stretch several times on each leg as you gain experience.

Another effective Calf Stretch involves using a stair step or an exercise step platform. Stand with the balls of your feet securely on the platform, allowing your heels to hang off the edge. Facing a wall for balance, gently lower your heels below the level of your toes, creating an extended stretch in your calf muscles. Be cautious not to over-extend, especially if you’re new to this stretch. Start with traditional Calf Stretches on flat ground to build flexibility and experience before attempting this more advanced variation.

Hamstring Stretches:

Sit on the floor with both legs extended straight in front of you. Keeping your back straight, lean forward from your hips and reach toward your toes until you feel a stretch along the back of your thighs. Lean in and out in a fluid and controlled motion. A slight bend in your knees is ok, don’t over-extend them, and be careful not to over-extend your hamstrings. Start with two to three times twice a day.

A variation of this that I find particularly effective is to stand with your foot resting on a chair seat or similar and your leg outstretched. Lean forward from your hips reaching for your toes until you feel the stretch along the back of your thighs, as in the previous example. Once again, keep the in and out motion fluid and controlled without over-extending.

Quadriceps Stretches:

Stand tall, and if needed, use a wall or chair for support to help with balance. Bend one knee and bring your heel toward your glutes, holding your ankle with your hand. Gently pull your ankle higher to feel a stretch along the front of your thigh, keeping your knees aligned and close together. Hold this position for about 15 to 30 seconds, then switch legs. Repeat the stretch two to three times on each side for full benefit.

Tip: Make Stretching Part of Your Pre-Run Routine. Incorporate these same stretches into a warm-up routine before your run to prepare your muscles and reduce the risk of cramps. These pre-run stretches help improve flexibility, boost circulation, and help your body transition smoothly into running mode. Spend 5–10 minutes stretching before each run and make it a habit.

The Power of Massage: Loosening Tight Muscles.

When a leg cramp strikes, massage can be a simple yet effective way to relieve the pain and help the muscle relax. By improving blood flow and reducing muscle tension, massage can speed up recovery and provide instant relief from the cramp.

Use your hands to gently knead or rub the cramped area, work in slow, circular motions with your fingers or palms, to help the muscle relax and release, but avoid pressing too hard as the muscle may still feel tender.

Get yourself a foam roller or massage ball, these can be excellent for deeper pressure on tight muscles. Roll gently over the affected area, focusing on spots that feel particularly tight or tender. Regular use of massage tools can also help prevent cramps by keeping muscles supple and relaxed.

I find that using a knobby foam roller works wonders for massaging my calves and hamstrings, whether it’s right after a run or the following morning. Just remember to avoid rolling directly under your knees, as this area contains sensitive tendons that could be easily damaged.

Massage is not just about treating cramps in the moment—it can also be part of your long-term strategy to keep your muscles healthy and ready for your next run.

Heat or Cold? When and How to Use Them.

Using heat or cold therapy can be an effective tool when it comes to managing leg cramps. Let’s take a look at when and how to apply each method to get the best results for muscle relaxation and recovery.

Heat Therapy:

Applying heat to a cramped muscle can work wonders to help it relax. Heat increases blood flow to the affected area, loosening tight muscles and easing discomfort. You can use a warm towel, heating pad, or even take a warm bath to help the cramp subside. For runners, this can be especially helpful after a long run when your muscles may feel tight and fatigued.

TIP: If you’ve just finished a run and feel a cramp coming on, jump into a warm shower or soak your legs in the bath to relax the muscles and prevent the cramp from worsening.

Cold Therapy:

Once the cramp has eased, switching to cold therapy can be beneficial. Applying a cold pack wrapped in a towel to the sore area helps to reduce any lingering pain and calm inflammation. This is particularly useful if the cramp has left the muscle feeling tender or swollen.

TIP: Keep an ice pack or gel pack in your freezer so it’s ready to go when you need it. Even a bag of frozen peas wrapped in a tea towel can work in a pinch!

Experiment with these hot or cold therapies to find what works best for you. By alternating heat and cold therapy as needed, you can treat both the immediate pain of the cramp and the aftereffects, helping your muscles recover faster and get you back to running comfortably.

DID YOU KNOW?: Using heat on sore muscles doesn’t just ease the pain—it boosts blood flow, delivering oxygen and nutrients to help the muscle recover faster. On the flip side, cold therapy, like an ice pack or cold plunge, reduces inflammation and numbs nerve endings, helping with soreness after a tough workout. Combining both can be a simple yet powerful way to support recovery and keep your muscles in top shape!

Preventing Leg Cramps In Runners: Proactive Strategies.

While it might not be possible to completely eliminate leg cramps—especially if you’re prone to them—there are plenty of preventative measures that can help reduce their frequency and severity.

This has certainly been my experience, I know how seemingly unpredictable leg cramps, particularly in my calves, can be. However, by consistently applying the management and treatment strategies shared in this blog post, I’ve significantly decreased both the number and intensity of my cramps.

Let’s dive into some of the strategies I use—ones you can try out for yourself to see what works best for you:

Stay Hydrated: The Importance of Proper Fluid Intake.

Proper hydration is essential for both overall health and preventing leg cramps. Dehydration, when paired with muscle fatigue, is thought to be one of the leading contributors to cramping.

So, to stay adequately hydrated:

• Monitor your urine colour: Aim for a pale yellow to near clear colour, which indicates proper hydration. Dark yellow suggests you need to drink more water.
• Adjust for exercise: Any exercise, especially in warm weather, needs extra fluids to replace what’s lost through sweat. For runners, plan your route to include public drinking fountains, or take along a water bottle—these can be hand held or attached to a running belt. Another idea for extra long runs, or trail runs, is a hydration backpack, these have a water bladder inside and a drinking hose attached to the shoulder strap for easy access while you run, here’s an example.
• Incorporate electrolytes: Use an electrolyte drink during long runs or intense training sessions. Important electrolyte nutrients like sodium, potassium, and magnesium help maintain the balance of fluids in your body. I’ve found that taking in electrolytes after the 25k mark of any long run makes a big difference, especially in warmer weather. It’s also a good ideal to have an electrolyte drink post longer or more intense sessions to aid recovery and keep cramps at bay.

TIP: Electrolyte replacement products come in a variety of formats, so you can find the one that works best for you. Options include tablets that dissolve in water, powders to mix into your drink, and even concentrated liquid formulas. Personally, I recommend trying products like LMNT—it’s an easy and effective way to replenish your electrolytes during or after a run. (Just to be clear, I’m not affiliated with them—I just really like their products!)

Magnesium and Potassium: Nutritional Solutions.

Electrolytes like magnesium and potassium play a key role in muscle function. Magnesium, in particular, helps regulate muscle contractions, while potassium supports proper nerve signalling. A deficiency in either can increase the likelihood of cramping.

• Magnesium-rich foods: Add almonds, spinach, cashews, avocados, black beans, tofu, and brown rice to your meals.
• Potassium sources: Bananas, sweet potatoes, avocados, and oranges are great options.
• Supplements: If diet alone isn’t enough, many runners, including myself, find magnesium supplements beneficial. You can find supplement capsules that contain both magnesium and potassium for convenience.

Daily Stretching: Building a Routine That Works.

We’ve already covered stretching in detail, but it’s worth emphasising how important it is to establish a regular stretching routine. Incorporating stretches into your morning and evening routines, as well as before your runs, can make a big difference in reducing both the frequency and severity of leg cramps.

Start your day with some gentle stretches, like the ones mentioned earlier in this post, and experiment to see which ones feel most effective for you. Don’t forget to include dynamic (not static) stretching and easy running before your run hit-outs, especially on colder days, to properly warm up your muscles and prepare them for activity. A consistent routine can go a long way in keeping cramps at bay!

Nighttime Adjustments: Managing Foot Position While Sleeping.

Nighttime cramps can often occur due to the position of your feet during sleep. When your toes are pointed downward (plantar flexion), your calf muscles can tighten, making them more prone to cramping.

• Pillow positioning: If you sleep on your back, place a pillow under your knees to slightly elevate them.
• Bedding adjustments: Avoid heavy blankets or tucked-in sheets that press your feet downward. Opt for lighter bedding that doesn’t restrict foot movement.
• Stomach sleepers: Try letting your feet hang off the edge of the mattress to reduce pressure on your calves.

Massage as Prevention: Regular Maintenance for Your Muscles.

Massage is not just a recovery tool—it’s also a great preventative measure for tight muscles.

• Sports massage: Regular sports massage sessions with a professional can do wonders for releasing muscle tension and keeping your legs in great shape. Ever noticed the massage tents at the finish line of big marathon events? There’s a good reason they’re there! After long-distance races, your leg muscles are more prone to cramping as your body cools down. Taking advantage of these post-race massage services can help prevent cramps and ease tightness—especially if you know you’re prone to cramping after long races.
• Foam rolling: Use a foam roller to target tight spots in your calves, hamstrings, and quadriceps. Roll gently over each muscle group, focusing on areas that feel particularly tense.
• At-home massage: Even a few minutes of self-massage after a run can improve circulation and reduce the risk of cramps later on.

DID YOU KNOW?: Regular sports massages can increase your range of motion and overall muscular flexibility, which is thought to help prevent injuries by keeping your muscles primed for movement and less prone to strain? This is particularly beneficial for runners.

When to Seek Medical Help: Knowing When It’s Serious.

For most people, leg cramps are short-lived, lasting only a few seconds to a couple of minutes. While they’re often more of a painful nuisance than a serious issue, there are times when persistent or severe cramping could indicate an underlying problem that requires medical attention.

If you find yourself experiencing frequent, prolonged, or extremely painful leg cramps that interfere with your daily life or sleep, it’s important to consult a doctor. They can assess whether the cramps are linked to:

• Vitamin or Mineral Deficiencies: Low levels of magnesium, potassium, or calcium may cause muscle cramping. Blood tests can help pinpoint any deficiencies.
• Medication Side Effects: Some medications, such as diuretics, statins, or blood pressure drugs, are known to increase the likelihood of cramps. Your doctor may adjust your prescription if this is the cause.
• Circulation Issues: Conditions such as peripheral artery disease (PAD) can restrict blood flow to the legs, leading to cramps, particularly during exercise.
• Diabetes: High blood sugar levels can affect nerves and muscles, causing cramps or other discomfort in the legs.
• Neurological or Muscular Disorders: In rare cases, cramps can be a symptom of more serious conditions, such as nerve compression, multiple sclerosis, or other neuromuscular disorders.

When to Act Quickly.

Seek immediate medical attention if your cramps are accompanied by:

• Swelling, redness, or warmth in the leg (possible blood clot).
• Muscle weakness or numbness.
• Cramps occurring after a leg injury.
• Significant pain that doesn’t subside after stretching, hydration, or other treatments.

While most leg cramps are manageable and are generally not cause for alarm, it’s always better to err on the side of caution if you’re concerned about their severity or frequency. Identifying and addressing the root cause with the help of a healthcare professional can provide relief and peace of mind.

Wrapping It Up: Managing and Preventing Leg Cramps In Runners.

As we’ve seen, most leg cramps are mild, short-lived, and usually nothing to worry about. That said, for runners, they can be more than just an annoyance—they can throw off your training, interrupt races, or even disturb your sleep. That’s why it’s so important to take proactive steps to manage and prevent them.

There’s no one-size-fits-all solution to stopping leg cramps, but a combination of the strategies we have explored, can significantly reduce their frequency and severity—this has certainly been my experience.

Key takeaways include:

• Stay Hydrated: Proper fluid and electrolyte intake before, during, and after runs is crucial, especially for long-distance training or in hot weather.
• Stretch Regularly: Building a routine that includes daily stretching and dynamic warm-ups before runs can help keep your muscles flexible and reduce the risk of cramping.
• Address Nutritional Deficiencies: Ensuring you get enough magnesium, potassium, and sodium through food or supplements can support optimal muscle function.
• Massage and Recovery: Incorporate regular massage, foam rolling, or heat and cold therapy into your routine to relieve tension and promote recovery.

While treating leg cramps is something you can often handle on your own, don’t hesitate to consult a doctor if your cramps are severe or persistent—they may be linked to underlying health issues.

I’ve been living with leg cramps—especially in my calves—for over twenty years as a runner. But with research and experience, I’ve learned how to largely keep them at bay and how to handle them quickly if they do pop up. With the tips and strategies I’ve shared in this post, you can manage your leg cramps too.

Finally, I’d love to hear from you! Have you experienced leg cramps? What methods have worked for you to manage or prevent them? Share your tips and experiences in the comments section below—I’d love to learn from our running community.

Run Strong

Steve

FAQ’s About Leg Cramps In Runners.

---

This article is for information purposes only and is not a recommendation to act on any of its content. It is always recommended you consult your healthcare practitioner before engaging in any activity that may affect your health.

---

Share this