Should I Size Up or Down for Running Sneakers?
Choosing the right pair of running sneakers is crucial for comfort, performance, and injury prevention. One of the most common dilemmas runners face is whether to size up or down when purchasing their running shoes. This decision can significantly impact your running experience, and getting it right is essential for both casual joggers and competitive athletes alike. In this article, we’ll explore the factors that influence sizing decisions, the consequences of incorrect sizing, and how to determine whether you should size up or down for your next pair of running sneakers.
Understanding the Importance of Proper Sizing
Before diving into the specifics of whether to size up or down, it’s important to understand why proper shoe sizing matters in the context of running. Running involves repetitive impact on your feet, and ill-fitting shoes can lead to a variety of issues:
Blisters and hot spots caused by friction from shoes that are too tight or too loose. Black toenails due to toes hitting the front of the shoe during downhill running or long distances. Foot pain, such as plantar fasciitis or stress fractures, which can be exacerbated by improper support or fit. Reduced performance due to discomfort or instability in the shoe.Because of these risks, it’s essential to find a shoe that fits your foot shape and running style perfectly.
Why You Might Need to Size Up
There are several scenarios in which you may want to consider sizing up when buying running sneakers:
1. Foot Swelling During ExerciseYour feet naturally swell during long runs or intense workouts. Studies have shown that foot volume can increase by up to 5-10% during prolonged physical activity. If you buy shoes that fit perfectly when you’re at rest, they may feel tight or uncomfortable once your feet swell during a run.
Tip: Try on running shoes later in the day when your feet are slightly swollen rather than in the morning when they’re smaller.
2. Toe Clearance and Downhill RunningWhen running downhill, your feet tend to slide forward in your shoes. If there isn’t enough room in the toe box, your toes can repeatedly hit the front of the shoe, leading to bruised or black toenails. This is especially common in trail runners or ultramarathoners who encounter varied terrain.
Tip: Aim for about a thumb’s width (approximately ½ inch) of space between your longest toe and the end of the shoe.
3. Thicker Socks or Cold Weather RunningIf you run in cold climates, you might wear thicker socks, which can compress the foot and require a slightly larger shoe to accommodate the extra volume. Similarly, if you tend to wear double-layer socks for blister prevention, sizing up can help prevent tightness.
Tip: Bring your running socks to the store when trying on shoes to get a more accurate fit.
4. Different Brands and Models Fit DifferentlyNot all running shoes are created equal. Some brands are known for a narrow fit (e.g., Nike), while others offer a wider last (e.g., Altra or Topo Athletic). Even within the same brand, different models can vary in length and width. It’s not uncommon to wear a half or full size up in certain brands or models to achieve the right fit.
Tip: Always try on shoes in person if possible, or order multiple sizes online and return the ones that don’t fit.
When You Might Need to Size Down
While sizing up is more common in running shoes, there are situations where you might need to size down:
1. Too Much Toe RoomWhile toe clearance is important, too much room can cause your foot to slide forward, leading to inefficient push-off and potential instability. If your heel is secure but your toes are sliding forward or your foot feels like it’s floating in the shoe, you may need to go down a half size.
2. Heel SlippageA shoe that is too long can cause your heel to lift during your stride, which may lead to blisters or an unstable feel. If you notice heel slippage but the toe box feels fine, consider sizing down for a more secure fit.
3. Performance-Oriented ShoesSome racing flats or speed-focused shoes are designed to have a snugger fit to maximize responsiveness and reduce weight. In these cases, a slightly tighter fit may be appropriate, especially if you’re using them for shorter distances where foot swelling is less of a concern.
Tip: Performance shoes should still allow for some toe room and should never cause pain or pressure points.
How to Determine the Right Fit
Here are some practical steps to help you decide whether to size up or down when purchasing running sneakers:
1. Measure Your Feet RegularlyFeet can change size over time due to age, weight gain, or injury. Have your feet measured at a specialty running store or use a Brannock device at home to get accurate measurements.
2. Try On Shoes in PersonIf possible, visit a running specialty store where staff can help you determine the best size and model for your foot type and gait. Many stores offer treadmill testing to simulate real running conditions.
3. Walk and Jog in the ShoesDon’t just walk around the store—simulate the movement your feet will experience during a run. Walk up and down stairs, jog in place, or even do a few strides in the parking lot.
4. Check Toe Room and Heel Fit Toe Room: There should be enough space to wiggle your toes without feeling cramped. When you bend your toes, they shouldn’t hit the front of the shoe. Heel Fit: The heel should feel snug but not tight. There may be some initial slippage, but after breaking in, the heel should lock in place. 5. Break-In PeriodSome shoes require a break-in period. If the shoe feels slightly tight out of the box, give it a test run. However, never ignore pain or pressure points—those won’t go away with time.
Consider Foot Shape and Gait
Your foot shape and gait pattern can also influence whether you should size up or down:
High Arches or Narrow Feet: May benefit from a snugger fit or additional insoles to prevent slippage. Flat Feet or Wide Feet: Often require more room in the toe box and may need to size up or opt for wide sizes. Overpronators or Supinators: These gait types may need more structured shoes that offer better midfoot support, which can also affect sizing.The Role of Socks and Inserts
What you wear inside your shoes can impact fit:
Socks: As mentioned earlier, thicker or moisture-wicking socks can change how a shoe feels. Always try shoes with the socks you plan to run in. Orthotics or Insoles: If you use custom orthotics, they will take up space in the shoe and may require a larger size or a model with a removable insole.Online Shopping Tips
If you’re shopping online, here are a few tips to help you make the right sizing choice:
Read Reviews: Look for feedback from other runners about whether the shoe runs small or large. Check Return Policies: Make sure the retailer offers free returns or exchanges. Order Multiple Sizes: If available, order your usual size plus a half size up and down. Know Your Foot Measurements: Use a Brannock device or have your feet measured at a store before ordering online.Final Thoughts
Deciding whether to size up or down for running sneakers depends on a variety of factors including foot swelling, terrain, sock thickness, shoe brand, and individual foot shape. While there is no one-size-fits-all answer, the key is to prioritize comfort, stability, and protection against injury.
In general, it’s safer to size up slightly than to size down, especially for long-distance running or trail running. However, ensure that the heel and midfoot still fit snugly to avoid instability or blisters.
Ultimately, the best way to determine the right size is to try on multiple pairs, walk or jog in them, and listen to your body. If something feels off, it probably is. Investing time in finding the right fit will pay off in the long run—literally.
Summary: When to Size Up or Down
ScenarioAction Feet swell during runsSize up Downhill or trail runningSize up Thick socks or cold weatherSize up Shoe feels tight out of the boxConsider sizing up Heel slippageConsider sizing down Excessive toe roomConsider sizing down Performance or racing shoesMay size down slightly Different brands/modelsTry multiple sizesBy following these guidelines and understanding your own foot needs, you can make an informed decision and find the perfect fit for your running journey.