If you find this near impossible, cut your run to 25-30 mins.

Rather than just running at the same pace every day, (the lunchtime plod!), vary the pace from time to time. Try some of these sessions, which will fit into your available time.

1. A 5 minutes run to warm-up, followed by intermittent efforts of 30 seconds, 45 seconds, 60 seconds, 90 seconds, 2 minutes, 90 seconds, 60 seconds, 45 seconds, 30 seconds, with one minute of easy paced running in between each effort as a brief recovery, followed by a 10 minutes of easy paced cool-down running.

2. A 7 minute warm-up run, 3x3 minute efforts (3 minute jog in between) 10 minute cool-down run.

3. A 10 minute, easy-pace warm-up, 10 minutes hard at race pace (10km), 10 minutes cool-down.

Another speed session you can try is: 10 minutes easy pace warm-up, then a mile at your 10 km pace, then jog to recover for 5 minutes. Then run a mile at your 5 km pace, jog to recover for 5 minutes. Then run almost 'flat out' for one minute with a minute jog recovery. Repeat this twice, finally jog to cool-down with the time you have left.

Run a steady warm-up mile, followed by 8x100 metre sprints. Finish off with a mile cool-down run, at an easy pace.

Chris Williams is an exercise physiologist and former Great Britain triathlete - check out his columns in www.Channelhealth.tv for more information.