As our official footwear partner, Brooks are pros in finding your perfect fit for happy feet. Experts on everything running-related, Brooks can also help with some of the common problems runners might face. And one of the most common of all? Heavy legs.
If you’re a regular runner, you’ve probably experienced your fair share of heavy legs, a.k.a. runs where you just can’t seem to shift out of first gear. Your legs are like lead, pace is a challenge and everything feels more sluggish than usual.
But what causes heavy legs, and how can runners avoid them? Read on to find out more.
Overdoing it
One of the main reasons heavy legs hit is because you’re overdoing it, either with too many miles or too much strength training.
Don’t get us wrong – of course you need miles in your legs if you’re training for a big event, and we’re the first to sing the praises of strength training for helping build stamina and avoid injury. But the running (and training) bug can be addictive, putting stress on your body and leading to physical and mental fatigue.
The solution? It’s all in the planning. Get yourself a training plan suitable for your distance and level (we have plenty here) and stick to it. Schedule your strength training around your running and avoid doing too much around your long run days. Your legs will soon be feeling fresh again.
Skipping rest days, warm ups and cool downs
Even if it feels counterintuitive, rest is just as important as running. Pay attention to the rest days on your training plan and don’t skip them, no matter how tempting it might be. Respect the pace too, and don’t treat every run like a speed session, or you might find that you’ve got nothing left when you really want – or need – to up the tempo.
We’re all guilty of heading out the door without a proper warm up or missing out a cool down from time to time, but try not to make a habit of it. Warming up and cooling down doesn’t have to take ages, and it’s a great way of avoiding stiffness and those dreaded heavy legs. Need to shake up your warm up or cool down? Check out our tips.
Running form
When was the last time you thought about your running form? Taking too-big strides, hitting the ground heel first or an uneven gait can all put excessive strain and pressure on your body, leading to issues like heavy legs.
Our advice? Pay attention to your posture, relax your shoulders, drive forward with your arms (but don’t let them cross your body), hit the ground with the front of your foot rather than your heel and keep your core engaged. Need more tips for fine running form? Take a look here.

Fuel and hydration
When you’re training, you need a balanced, healthy diet to provide the fuel your body needs. And if you’re struggling with heavy legs, it might be worth looking at the amount of carbohydrates you’re taking on board.
Here’s the science bit: carbs are stored in your muscles as glycogen, which your body relies on when running. If glycogen stores are used up too quickly, i.e. because you’re not consuming enough carbs, you’re going to find you’re running on empty – literally. And that’s when heavy legs can hit.
Running low on iron can also cause energy issues because iron plays such an important role in transporting oxygen to your muscles. Low on iron? Low on oxygen. Up your intake of red meat, beans and/or leafy veg, or perhaps consider a supplement – although you might want to check with a doctor first. Get diet smart with some training advice here.
Dehydration is another cause of heavy legs – and remember, it’s not just about drinking during a run, but before and afterwards, too. We’ve got all the water-related intelligence you need here.
Sleep
Getting enough sleep – and for most adults that means around 7-8 hours per night – makes early runs more bearable. Packing in more Zzzzs means more recovery time, so give yourself the best chance of a great night with good sleep hygiene, making sure your room is the right temperature and sticking to a regular (ish) routine.
The wrong shoes
Feet come first for runners, and if you’re wearing the wrong shoes you might find your legs are having to work harder. It’s vital that your running shoes fit well, give you the right kind of support and encourage good running form. Brooks’ Shoe Finder takes five minutes and helps you find the perfect fit to combat heavy legs – try it here.