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Are you running too fast? Maybe try to spend some time running slower ....

Perhaps things you never thought you’d hear me say….

Fast is fun, we know that, but it’s important not to spend too much time running at a pace that is moderate to medium intensity (perhaps your current comfort or “go-to” pace?)  as it can both increase injury risk and result in levels of fatigue which mean it's difficult to make speed workouts intense enough to be beneficial. 

Slower running helps you develop your aerobic system while placing significantly less stress on your musculo-skeletal system than a faster pace and still enables high intensity sessions to be performed well. It’s this combination that together drive improvement across both aerobic and anaerobic energy systems so save your “fast fun” for speed specific sessions and slow down on your longer runs!

social group run

Does running slowly really build fitness?

Running at a steady or easy pace improves our muscular endurance & the amount of oxygen our muscles can extract from blood by building a more dense network of capillaries within the muscles and by increasing the number of mitochondria* in muscle cells. It also primes the heart, circulatory system and lungs, enhances the use of fat as a fuel (vs carbohydrate) and helps develop stronger, more resilient connective tissue. It achieves all this with much less stress on our joints, bones, muscles, tendons & ligaments than faster running. Equal or greater fitness adaptations can derive from higher-intensity ie faster running but with the associated cost of fatigue and stress on our bodies which, especially when combined with busy lives, can just be too demanding and lead to injuries.

How much slow, how much fast?

We can divide intensity into three zones of:

  • Low intensity (Zone 1): running composed mostly of aerobic long, low-intensity workouts

  • Moderate intensity (Zone 2): running at a moderate effort level

  • High intensity (Zone 3): running mostly composed of anaerobic short, hard efforts at high intensity and low volume

Frequently Zone 2 is our comfort zone and the one we think benefits us the most. If this is the case try to reduce the time spent there and instead increase the time in Zone 1 and also include at least one Zone 3 speed session in your week. Target spending the majority of your time on Zone 1 training; a lesser amount of Zone 3 training and least of all Zone 2 training and see how this feels.

One philosophy, known as polarized training proposes 80% in Zone 1, and 20% in Zone 3, with minimal/no time spent in Zone 2. Approaches differ but there is consensus about the real benefits to be gained from spending less time in the  Zone 2 comfort zone and making your slow runs really slow meaning you can make your fast runs much faster. 

How do I know I'm going slow enough?

You don’t need complex equipment to determine your lactate threshold** to define these zones, techniques like heart rate monitoring, perception of effort or even the talk test can be equally as effective.

  • Heart Rate: If monitoring heart rate something around 70 percent of your max heart rate is a good rule of thumb

  • Rate of Perceived Exertion (RPE): On easy days, listen to your body and try to keep your effort at or preferably below 5 on a scale of 1 to 10

RPE chart
  • Talk Test: You can hold a conversation while running

  • Nasal breathing: If you haven't got anybody with you to talk to then aim to maintain a pace where you can breathe in and out through your nose, rather than your mouth.

But how do I slow down?

If fast is fun, slow is….ermmmm, less fun? A bit boring? Time consuming? Ego-trashing? 

Strategies to overcome these feelings include:

  • Give every run a training purpose and write this down in a plan. If it’s a slow/easy/recovery run then set yourself a target pace/ heart rate/effort level that is sufficiently slow/low and really try to not go above it

  • Save time: run-commute or use slow running as a means of getting around.

  • Make it social:  instead of meeting friends for a coffee chat and run slowly at the same time. The talk test is a great way to gauge if you are running slowly enough, you should be able to have a conversation while running slowly. 

  • Come along to Hilly Fields Run Sessions new social runs. Free to join, everyone welcome. Soft start: Weds June 5th 6:30 - 7:30pm. They will include a warm up, a group run (all abilities catered for), cool down & stretching and lots of opportunities for chatting whilst running!

What about the fast running?

If slow runs are slow, fast runs should be fast, high intensity and hard work. Interval and hill training are great ways to do this, where periods of fast running are alternated with lighter recovery periods. Different lengths & intensities of interval target different fitness goals with some examples given below:

  • VO2 Max intervals: 30s to 6 minutes in duration with recovery time 50-100% of interval time. RPE 7-8/10 or Heart Rate 90% of maximum heart rate. Aim for 4-6 intervals depending on their length.

  • Anaerobic capacity intervals: 10-30 seconds efforts with recovery times of 2 to 4 times as long as the interval time. RPE of 8-9 depending on length or Heart Rate 95% of maximum heart rate. When you start doing these aim for 4-6, perhaps at the end of a slow run. Gradually build up the volume and intensity over weeks.

These sessions should always be preceded by a warm up including slow running & dynamic mobilisations and followed by cooling down & stretching. Hilly Fields Dawn sessions and 8 week series sessions are based around these faster intervals, doing them in a group is a great way to push yourself hard and drive the intensity that creates the training adaptation they are intended for.

And what about fast, continuous running, sometimes known as a “tempo” run, like pushing yourself towards a parkrun PB? These are great for teaching how to run at a constant, sustainable pace or effort over a certain distance or duration and increase aerobic capacity, but don’t underestimate the training load and stress they place on our bodies in terms of fatigue and musculoskeletal impact. They definitely have a part in a running routine, but if it’s too big a part compared with slower running and shorter, interval based speed sessions then you may be at greater risk of injury and also be too fatigued to access fitness benefits which should result from speed sessions.

*Mitochondria are the “powerhouses” of our cells, where the process of aerobic respiration (using oxygen to turn glucose into muscle fuel) takes place

**Lactate threshold: the intensity of exercise at which lactate begins to accumulate in the blood at a faster rate than it can be removed, and the physiological transition point between aerobic and anaerobic exercise


Science of Running: Chris Napier

Polarized Training Is the Fastest Way to Build Endurance Without Burning Out: Ashley:  Mateo Runners World March 2021

Running Well: Sam Murphy & Sarah Connors

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