Running for Fitness

There is probably no greater topic of controversy among runners than the ideal mileage.

As far as we know, aerobic capacity does not improve if you run more than 50 miles a week.  So if you are interested only in increasing your fitness, this is probably the maximum mileage you need to run.  You can, of course, maintain a good level of fitness on much less.

Running performance can continue to improve beyond 50 miles a week, however, even though aerobic conditioning does not.  The benefits of big mileage include improvements in the runner’s ability to burn fat, increased muscular endurance and maintenance of body weight. The upper limit for physiologically useful increases in mileage appears to be around 80-100 miles a week; though many elite athletes run 100-120 miles a week.

Most amateurs runners don’t run anything like this sort of distance each week.  Clearly, a number of factors affect the optimum mileage:

• lifestyle constraints, such as family and work commitments, and other leisure activities;
• the distances, if any, at which we want to race (marathon runners need a higher weekly mileage than 5km runners)
• our capacity to train before we get injured or ill; this is greatly affected by how we train, but there are also some inherited differences.

Here is a table setting out a rough guide of recommended mileages for runners of different experience at different race distances.[i] The judgement you make about weekly mileages will depend on your own circumstances.

Table 10.3 Recommended maximum weekly distances (miles)

Race distance	Beginner	Intermediate	Advanced
5km	10 – 20	15 – 25	30 – 40
10km	15 – 25	20 – 30	30 – 50
Half marathon	20 – 30	25 – 35	35 – 50
Marathon	30 – 40	40 – 50	40 – 60

You don’t need to run these distances all year round: these are weekly averages in the peak weeks before your race.  You should take regular breaks during the year – reducing your mileage, and then build up again.

If your goal is simply to keep fit, then you should be aiming for about 30 miles a week.

How rapidly to increase your mileage

You should not increase your weekly mileage too rapidly if you want to avoid injury or illness.  A good rule of thumb is that below 20 miles a week you should not increase your weekly mileage by more than 2 miles a week; above 20 miles a week, you should not increase your weekly mileage by more than 10% a week.  So if you are currently running 10 miles a week, you should not increase to more than 12 miles next week; and if you are running 35 miles a week, you should not increase to more than 38½ miles the next week.

This is a very important guideline. All experience shows that excessively rapid build-up in training mileage is one of the most common causes of injuries.  Many new runners think that they can be the exception to the rule, because they feel they can go further than this.  Sadly, this enthusiasm often ends in tears.

How many times a week to run

If running is your main exercise, you should aim to run 3-4 times a week, in order to reap the full health benefits (see Chapter 1).  But runners who set themselves more demanding performance goals will need to run 5-6 days a week, giving themselves one or two rest days a week.

Elite runners will often run twice a day on at least some days of the week.  For example, they may do a track session in the morning, and a recovery run in the evening.  These runners may therefore run 10-12 times a week.  Even elite runners generally take one day a week off completely, but some only rest on one day a fortnight.

Running twice a day can have advantages if you are trying to do a big weekly mileage, since it seems to be less draining to run two six mile runs than one twelve mile run in a day.  But remember that there are time overheads, such as the time it takes to change, shower and recover, which you will have to accommodate twice. It is physically demanding to run twice a day, and you should not contemplate it until you have been running for a few years.

The length of the long run

A cornerstone of the running week for many runners is the long run, especially for runners focusing on distances more than 1500m. The length will vary according to the distance you want to race. Endurance runners will typically do one long run a week; shorter distance runners may do one long run a fortnight.

The long run should be between one quarter and one third (certainly less than half) of your weekly mileage.  So if you are running 10 miles a week, your long run should be around 3-4 miles.

The table below sets out recommended distances for long runs.  These are the peak distances for your long run during your training schedule, which you will build up to.

Table 10.4 Long run distances (miles)

Race distance	Beginner	Intermediate	Advanced
5km	3 – 6	5 – 8	8 – 12
10km	5 – 8	6 – 10	10 – 15
Half marathon	10 – 13	11 – 15	13 – 20
Marathon	18 – 20	18 – 20	18 – 22

---

[i] Adapted from Bob Glover and Shelly-lynn Florence Glover, The Competitive Runners Handbook, 2^nd Edition, 1999.

[ii] Adapted from Bob Glover and Shelly-lynn Florence Glover, The Competitive Runners Handbook, 2^nd Edition, 1999.