Leg Cramps While Cycling: Causes, Prevention, and the Fastest Way to Stop Them

It comes on unexpectedly, and it comes on fast. You’re enjoying a weekend ride when, out of nowhere, a searing pain shoots through your leg. You can hardly pedal enough to pull off the side of the road, and you’re doing everything you can not to scream.

You’ve been hit with a leg cramp — the scourge of many cyclists. More often than not, these cramps hit late in the ride, after you’ve been working your legs for a long time. Aside from causing excruciating pain, they can leave your calf, thigh, or quad feeling like it’s tied in a knot, making it difficult to finish your ride.

Leg cramps can ruin a ride in a matter of seconds, leaving you sidelined and unsure what happened. This ride didn’t seem so different, you think. Where did this come from? They can hit for many different reasons, but Coach Darryl MacKenzie gave us the scoop on the three biggest causes of leg cramps while cycling and how to prevent them. Even better, he’s got the magic pill for how to stop leg cramps while cycling.

Jump Link: Heard a rumor about using Tums for muscle cramps? Jump to that section below.

Why Do Cyclists Get Leg Cramps?

Based on Darryl’s decades of coaching experience, most cycling leg cramps come down to a few root causes. They’re rarely random, even if they feel that way in the moment.

Let’s look at three of the most common reasons riders get leg cramps when cycling.

Pushing Beyond Your Conditioning

This is the most common cause of leg cramps during bike rides: You simply tried to go too fast or too far compared to your typical workout over the last six weeks or so. Often, this is why leg cramps show up late in a ride — or even after you’ve finished — when muscles are already fatigued.

Let’s say you’ve been riding a 30-mile ride at 14 miles an hour, but you ride with a new group that’s going 45 miles at that same pace. Or they’re going 30 miles at 16 mph. Either way, you’re setting yourself up for leg cramps during your ride.

Dehydration on the Bike

Dehydration is a very common cause of leg cramps while cycling as well, and it’s especially common on long, hot rides. Ultimately, you didn’t drink enough, you’ve been sweating a lot, or both.

You may not realize just how much water you can sweat out while cycling in hot weather. On one particularly hot ride, Darryl recalls losing a full 5.3 pounds from the start of the ride to the finish. That’s a lot of water to lose, and your legs will let you hear about it.

Electrolyte Imbalance

Electrolytes — minerals such as sodium, potassium, and calcium — are essential for your body in many ways, not the least of which is muscle function. When you're low on these minerals, muscles will stiffen and cramp much more easily. 

As you sweat, you lose electrolytes rapidly. And, again, the longer and hotter your workout, the more you’ll lose. Darryl has even seen his gloves turn white with sodium after sweating heavily on a ride. That’s another sure sign that leg cramps are just around the bend.

How to Prevent Leg Cramps While Cycling

Cramps aren’t always avoidable, but in many cases they’re preventable. Most cycling leg cramps come down to preparation — how you train, how you hydrate, and how well you replace what your body loses on the bike.

Coach Darryl recommends several tips to keep leg cramps from ruining your rides:

• Build up your training gradually. The most common cause of cycling leg cramps is pushing beyond what your body is ready for. If you increase distance, ease up on pace. If you increase pace, shorten the ride. Trying to do both at once, especially compared to what you’ve been riding over the last four to six weeks, is a recipe for cramps late in the ride or even after cycling.
• Match effort to the conditions. Riding farther or harder than usual becomes even riskier in heat or humidity. Hot weather accelerates fatigue and fluid loss, making leg cramps while cycling far more likely. Adjust expectations when conditions change.
• Stay ahead of hydration. Drink consistently before your ride, and don’t wait until you feel thirsty to start drinking on the bike. Once dehydration sets in, it’s difficult to catch up mid-ride.
• Replace electrolytes, not just fluids. For rides longer than about 90 minutes, water alone often isn’t enough. Sports drinks or electrolyte supplements help replace both fluids and electrolytes, reducing the risk of leg cramps while cycling, especially in hot conditions.
• Prepare before the ride starts. On especially long or hot rides, it can help to increase sodium intake in the day or two beforehand. Starting the ride with depleted electrolytes makes cramps much more likely later on.
• Pay attention to early warning signs. Tightness, twitching, or a “heavy” feeling in your legs can signal trouble ahead. Backing off slightly and rehydrating early can sometimes prevent a full-blown cramp from developing.

What to Do When a Leg Cramp Hits Mid-Ride

Even with perfect preparation, leg cramps can still happen. When they do, your priority is simple: relieve the cramp safely and as quickly as possible so you can regain control and decide whether you can continue riding.

Here’s what to do when a leg cramp strikes during a bike ride:

1. Slow down and signal right away. Let riders around you know what’s happening, especially if you need to coast or stop suddenly. A cramp demands immediate attention, and maintaining control of the bike comes first.
2. Stretch the affected muscle immediately. Lengthening the cramped muscle is the fastest way to relieve the pain. For a calf cramp, straighten your leg, lower your heel, and pull your toes upward. If your hamstring cramps, extend the leg and stretch the back of the thigh. Experienced riders can sometimes do this while coasting, but many cyclists will need to stop.
3. Unclip carefully. If you do stop, always unclip with the leg that isn’t cramping. Trying to unclip with a locked-up muscle increases the risk of a fall.
4. Massage the muscle if needed. Light massage can help the muscle relax, especially if the cramp doesn’t release right away with stretching alone.
5. Address hydration or electrolytes if possible. If dehydration or low electrolytes may be contributing, drink fluids or take electrolytes as soon as you can. Be realistic, though — once dehydration sets in, it can be hard to fully reverse mid-ride.
6. Know when to call it a day. Sometimes the smartest move is to slow down, take a shortcut home, or end the ride early. Pushing through a lingering cramp can make it worse and increase the risk of injury.

Do Tums Help With Leg Cramps While Cycling?

When cramps strike, quick action matters — but Coach Darryl also knows a surprisingly effective option that many cyclists keep on hand for stopping cramps in progress. If you’ve ever heard cyclists talk about using Tums for leg cramps, you might be skeptical. An antacid doesn’t exactly sound like a performance tool. But after decades of riding and coaching, Darryl MacKenzie swears by them for one very specific situation: quickly stopping a leg cramp that’s already happening.

Why Tums Can Help Stop Active Muscle Cramps

Tums are made from calcium carbonate. Calcium is one of the key electrolytes involved in muscle contraction and relaxation, and when levels drop too low, your muscles are far more likely to seize up.

When you chew a Tums tablet, you’ll quickly absorb calcium carbonate through your mouth and digestive system. For some riders, that rapid calcium boost is enough to help cramped muscles relax again — often within seconds. That’s why many cyclists reach for Tums for muscle cramps rather than waiting for food or slower-absorbing supplements.

How to Use Tums for Leg Cramps

If you’re dealing with a cramp mid-ride, here’s how cyclists typically use Tums:

• Take one or two tablets as soon as a cramp starts.
• Chew them slowly and keep them in your mouth as long as possible.
• Stretch the cramped muscle at the same time for faster relief.

It’s important to note that Tums are not a preventive solution. They’re best reserved for active cramps, not taken routinely before or during rides. Calcium carbonate isn’t something you want to ingest constantly, and it won’t replace proper hydration, training, or electrolyte management.

Think of Tums as a kind of “magic pill” for leg cramps in progress — something to keep in your saddlebag for the moment a cramp hits, not a substitute for good preventive measures.

Final Takeaway: Be Prepared, Not Surprised

If you tend to get leg cramps during or after cycling, they’re not random. They’re usually the result of pacing, hydration, or electrolyte gaps. The good news is that preparation dramatically reduces how often they happen. Build gradually, drink consistently, and replace electrolytes before they run low. And if a cramp does strike mid-ride, act quickly: stretch the muscle, stabilize the bike, and use tools like Tums when appropriate. 

With the right approach, leg cramps don’t have to end your ride — they just become another cycling challenge you know how to overcome.

FAQs About Leg Cramps While Cycling

Can leg cramps happen even if I trained?

Yes. Even well-trained cyclists can experience leg cramps if hydration, electrolytes, pacing, or weather conditions aren’t managed properly. Fatigue accumulates over the course of a ride, and imbalances can trigger cramps, especially late in harder or longer efforts.

Why do leg cramps hit late in rides?

Cramps often appear late because muscles are fatigued and electrolyte levels are lower after prolonged effort. As dehydration and muscle strain build, the nerves controlling muscle contraction can misfire, making cramps more likely near the end of a ride.

Are calf cramps different from quad or hamstring cramps?

The cause is usually the same — fatigue, dehydration, or electrolyte imbalance. The difference is location. Calf cramps are most common while cycling, but quads and hamstrings can cramp too, especially during sustained climbing or high-intensity efforts.

Can dehydration cause cramps even in cool weather?

Absolutely. You lose fluids through sweat even when temperatures are mild. Because you may not feel as thirsty in cool weather, it’s easy to fall behind on hydration, increasing the risk of leg cramps during a bike ride.

Image by Pavel Danilyuk on Pexels