Long Runs to Build Endurance

The most important weekly run for amost all endurance runners.

All training is based around practice and recovery. To improve endurance you should improve your ability to run by repeatedly pushing your boundaries, in a sensible way. Then after a period of fatigue you come back stronger. Simply repeating the same activity does not push your boundaries, in the same way as racing every week does not.

Gradually increasing the distance of your longest runs is an effective method for most runners to both improve endurance and provide a base for harder training. Without being too detailed or technical, among other benefits long runs stimulate your body to store more glycogen, which is a key fuel your muscles use when running.

The overall mileage you cover over a period also matters, referred to as training volume.

How far? How fast? How often?

If you are a relatively inexperienced 5k runner, over time you need to build to 10km or 12km on your weekly long runs. Experienced half marathoners need long runs of over 25km.  It’s different for every runner and is affected by many factors. Mileage limits do increase over time and you should be thinking of years of healthy training, not be trying to build up to your maximum possible distance in a very short period. Incidentally, to be effective these long runs are continuous runs, not run/walks. If you need to walk, then you are too ambitious and should set shorter distances as your target until you are comfortable. This will help you physically and mentally.

Increasing your long run distance should not be done in a rush. An increase of total weekly volume of 10% for a maximum of three weeks is quite enough, you should then stay at that level for several weeks until your body adapts. Think of how many weeks it takes to alter a golf swing, or recall when you learned to drive and how long it took until it became natural behaviour. Adaptation typically takes 6 to 8 weeks.

The intensity of your long runs matters. They are not leisurely jogs but neither are they long sprints. If you have competed in 10k races, then you will have established what your 10k racepace is and can use that to calculate your guide pace for yoir long run. Go for a pace that is about 25% slower than your 10k race pace. (For example, if your 10k race pace is 5:10 min/km, pace your long run at 6:22 min/km). Even better is to start your long run at 33% slower than your 10k pace, increasing pace to 20% slower than 10k race pace by the end. (For example, if your 10k pace is 5:10 min/km start at 6:47 min/km and end at 6:07 min/km). The recovery day following your long run day should be resting or cross training, but not running.

If you have not yet competed in 10k races, or do not wish to, then a simple guide to your long distance run pace is to think about how you talk when running. You should find it Easy to talk and Easy to run. See table below. If during your long run, particularly as you tire, you are feeling out of breathe then slow down. Keep it Easy to the end.

Description of run pace





Perceived Exertion

Very easy


Just comfortable


Breathing reference

Very easy to talk in long sentences

Easy to talk

OK to talk in short bursts. Periods of silence

Hard to talk. Staccato

Graeme Loudain – September 2019

These notes are published as a general aid to all endurance runners. They are guidelines based on current best practice, intended to illustrate the points in the articles rather than provide a precise training schedule. They are written in a way to be of help to runners. Individuals will have their own requirements and the content of the notes will not suit all. Please use them in the spirit in which they are intended and modify them to suit your own needs. If you have suggestions for improvement, amendments or comment, please email gladmin@btinternet.com.