Unless you’re following a dedicated training plan, it can be hard to tell when you should speed things up and slow things down, let alone how far you should be running in the first place.

I’m definitely one of those runners who is guilty of going too fast too often – I’ll find myself trying to run my race day pace on a ‘relaxed’ 10k around the park and then wonder why I feel so dead afterwards. 

But just because many of us have felt targeted by TikTok videos and articles telling us to run slower, it doesn’t mean there isn’t space for running fast, does it?

To find out the benefits of long, slow runs v short, fast ones, we asked Ben Parker, co-founder and head coach at the running app Runna, to explain how each type of run can help us develop as runners, as well as how and when to make space for them in your running schedule. Here’s what he had to say.

While running fast all the time isn’t good for you, Parker says there are plenty of benefits to incorporating speed work into your routine – as long as you don’t overdo it.

“The average runner should look to spend around 20% of their weekly mileage going ‘fast’,” he explains. “This is a great way to challenge both our heart and lungs as well as our muscles to create the power to run fast – but running fast can be particularly intense on both our energy systems and body, hence why only a certain portion of our running should be done in this way.”

Adding ‘fast’ runs into your weekly schedule is important if you want to get quicker, Parker adds. This can be done in several ways, from doing a short, fast run to doing intervals and tempo workouts. 

There’s a reason why slow running gets so much attention online: it’s incredibly beneficial, no matter what stage of your running journey you’re at.

“Taking a run ‘easy’ is valuable for all runners for a number of reasons,” Parker explains. “It’s a great way to build your endurance and improve your running fitness without causing as much stress on the body as running faster – most runners should be looking to spend around 80% of their runs at an easy intensity.”

These long, slow runs are particularly effective for people looking to increase the distance they can run for, Parker adds.

This is because low-intensity or ‘zone two’ training – so known because it keeps your heart rate in the zone two category – can help to improve your lactate threshold, ie when the level of lactate in your blood is higher than at resting.

This is important because increasing your lactate threshold allows you to run faster and further using anaerobic energy – your body’s low-intensity, endurance energy source.

Doing less intense cardio work can also help to improve muscular and aerobic endurance because of the way it improves oxygen flow.

Indeed, as Performance Physique head coach Arj Thiruchelvam previously told Strong Women: “Zone two training is particularly effective at capillarisation, the process of increasing the number of capillaries that serve a muscle and thus improve your muscular and aerobic endurance by delivering oxygen to that area of the body.” 

As you’ve probably already gathered, doing a long, slow run is no ‘better’ for you than a short, fast one – it just depends on when and how you do them.

“Any good runner will do a balance of both long, slow runs and short, fast runs – your goals and current strengths and weaknesses will help to determine the balance as to what you should prioritise in your training,” Parker says.

“Generally I would suggest that someone looking to train for a marathon or beyond – if they should pick one – should prioritise the ‘long, slow runs’ while someone looking to get quicker over the 5k distance should prioritise the ‘short, fast’ style of run.” 

It’s clear that a good running routine should incorporate runs of different lengths and intensities – but what’s the best way to translate that into a training plan?

Parker recommends aiming for as much diversity as possible within the 80:20 split – 80% ‘easy’ runs and 20% fast runs. “You should look to do your fast running covering all different types of sessions from short sharp intense interval training to longer but still fast tempo workouts and hill workouts too, depending on what you’re training for,” he says.

And just because you’re doing an ‘easy’ run, doesn’t mean they need to be long – there’s such a thing as a beneficial short, slow run too. 

“We shouldn’t always feel that we need to finish a run having fully emptied the tank,” Parker explains. “By taking a run easy, it’ll allow us to improve our fitness and running ability somewhat while protecting us for a harder session later in the week.” 

Images: Getty