How to choose a sports bra

According to the latest research carried out by the Shock Absorber Sports Institute (SASI) at Portsmouth University, 9.5 million women in the UK are not supporting their breasts properly when they run. Could you be one of them?

Whilst we’ve summed up the best sports bras to be running in, here’s all you need to know on how your bra should fit and support you when you run.

Why wear a sports bra when running?

The average breast weighs between 250 and 300g and any unsupported movement – such as running – causes three-dimensional movement: up-down, in-out, and side-to-side. The SASI research also shows that on average, a woman's breast moves 9.08cm with every stride when running.

This can result in discomfort, chafing and strain on the breasts' supportive tissue – the Cooper’s ligaments – which in turn can eventually lead to sagging. Once stretched, the Cooper’s ligaments cannot revert back to their original position, so it’s important to support your breasts, no matter how far you’re running.

What size running sports bra should I buy?

There's no magic formula to finding out which bra size will fit you best. If you have never worn a sports bra before, start with your usual bra size but be open to trying on different sizes before you find the perfect fit. Like trainers, different bras will fit differently, so try a few before finding your perfect brand.  

Related: The best sports bras 2018 

How should a sports bra fit?

The first sign that you’ve got the right size when it comes to sports bras is the back band is at the same level all the way round. If it rides up, it’s too big.

Your sports bra should fit snugly, but not be too tight that you can’t breathe and you should be able to get no more than one finger under the band or in the cup.

What are the signs my sports bra doesn’t fit?

You’ll be able to tell if you’re wearing an un-supportive sports bra. Look out for the following:

1. Breast or back pain – if your breasts or back hurt, your sports bra isn’t doing its job. It might also mean that you’re wearing a bra with the wrong amount of support – you shouldn’t be wearing the same bra for yoga and running.

2. The bra band rides up your back, or you’ve got your bra on the tightest hook – even if the straps fit perfectly, it’s actually the bra band that does most of the work on a sports bra. The band should be snug, but not painfully tight.

3. The straps are digging into your skin – with a number of different styles to try, you’ll soon be able to work out which you prefer, yet whether it’s a wide-set strap or a racerback, if they are digging in the bra is not fitting right.

What are the different types of sports bras available?

Although there are a number of different styles, most sports bras can be divided into two categories:

1. Encapsulation bras have two cups like a normal bra, but with extra support.

2. Compression bras press your breasts against your chest, and are usually pulled on over your head. If you're opting for the former style, then make sure the centrepiece lies flat against the breastbone.

Related: The best affordable running kit for women 

What shape of sports bra best suits my breasts?

Trial and error is the best way to discover which brand, model and size fits your breasts best. Most retailers should be able to suggest a selection of bras that, based on your body shape and level of activity, will suit you best.

If you're shy about having a fitting in person, some online retailers provide knowledgeable customer support and a freepost returns if you're not happy.

Don't forget though, that the shape of your bra will have an impact on how effective it is in reducing movement while running. As with running shoes, many women will stick with the same model of bra once they’ve found the one that supports them best.

What level of support do I need in my sports bra?

Different bras offer different levels of support. The type you need will depend on your cup size and the type of exercise you do.

1. Low-impact sports bras, used for stretching or walking, are often cut like a crop-top and are, on the whole, made from thinner material.

2. Medium-impact sports bras are a mix between the two, these can sometimes be used for running, but are often not suited to larger-breasted women.

3. High-impact bras (for running) generally use less stretchy material, include supportive seams and overlays and are sometimes even underwired.

Running causes a large amount of breast movement compared with many other sports. Whilst the level of support required does vary according to bra size, whatever size you are it’s often recommend that you opt for maximum support.

Related: Running while female 

I'm smaller-/larger-chested than average, what sports bra should I wear for running?

Smaller-chested women may feel most comfortable wearing a compression sports bra. However, there is research to suggest that a properly structured encapsulation bra – which cups each breast individually – is more likely to give good support than a compression bra.

For larger cup sizes, encapsulating sports bras are definitely recommended; although some bras offer a combination of both encapsulation and compression.

What sports bra should I buy if I am pregnant or breastfeeding?

During pregnancy or when breastfeeding you will need the maximum support available. In addition, your bust size will change throughout your pregnancy, so consider buying an adjustable bra to avoid frequent replacements.

Some women find that wearing a crop top over a sports bra is the only way to stay comfortable when running during pregnancy.

Related: What to do if you lose your periods from running 

Why has my sports bra started to chafe?

Sports bras usually start to chafe when the elastic has begun to age. It can also occur more frequently on longer-distance runs – this is because of the increased movement of the bra against the skin, due to perspiration.

One solution is to tighten the rear-fastening by one notch before setting off. This can also be a solution if you've recently started running (or increased your training) and have lost weight.

Like running shoes, a new sports bra will also need be worn in, so to avoid any unexpected problems, best not to wear a new bra on race day!

How long does a sports bra last?

You’ll need to replace your sports bra every few months, or after around 30-40 washes. As a rule of thumb, bra experts reckon you will need three new bras for every one pair of running shoes.

The technical fabric of your sports bra will wear in the washing cycle, and its elasticity will diminish during use. To prolong the life of your sports bra, try not to tumble dry it: the heat will destroy the fabric on your bra. Like your everyday bras, experts recommend you hand-wash your bra, or put them in a lingerie bag in the washing machine for extra protection.