Colds, bad knees and weeks that fall apart

The rule is simple. Some situations complicate it, and I should be plain about them.

When you're ill. The floor doesn't apply to days when you're unwell. If you've a fever, a chest infection or anything that's put you in bed, rest. I haven't checked medical guidance on exercising through minor illness for this book, so I won't offer a rule about colds. Use your judgment, and ask a pharmacist or GP if you're unsure. When you're better, begin again with ten minutes. Don't try to make up what you missed.

Injuries and sore joints. If something hurts in a way that isn't the ordinary ache of effort, don't push through it for the sake of the rule. Often there's another option on your list that doesn't involve the sore part. A bad knee may still allow the counter press-ups, and a sore shoulder won't stop you walking. If a pain persists, see a GP or a physiotherapist. And if you've a long-term condition, the guidance in the preface applies. Get advice on what's suitable, and then apply the rule to that.

Warning signs. I'll repeat the caution from the preface. Chest pain, pain spreading to the arm, jaw, neck or back, or chest discomfort with sweating, sickness, light-headedness or breathlessness, means stop and call 999. Don't finish the ten minutes first.

The week that falls apart. Some weeks there's a crisis at work, a sick child or a funeral, and nothing happens at all. That's life and it isn't a failure. The important thing is what you do when the week ends. The old habit says to wait for a clean Monday and a clear diary. Chapter 8 explained why that's a mistake. The day you notice you've had a run of zeros is the day to do ten minutes. If it's a Thursday evening in your work clothes, do it then. You're not rebuilding a streak, because there never was one. You're doing today's ten minutes and nothing more.

Holidays and travel. Your anchors disappear when your routine does. Choose one for the trip. "Before breakfast, ten minutes' walk from the hotel door and back" works almost anywhere. Walking round a new place is one of the better ways to see it in any case.

When the old voice wins. There will be evenings when "it's not worth it" arrives and you agree with it and sit down. One evening means nothing. Chapter 8's finding applies to the new habit as well as the old plan, and a single missed opportunity doesn't undo it. Notice what happened. Were you hungry, was it raining and you had no wet-weather option, or had you left it too late in the evening? Adjust the plan, and do ten minutes tomorrow.

When the floor starts to feel like a ceiling. Some readers will find after a few months that ten minutes has become all they ever do, and they're content. That's a perfectly good outcome for health, and I wouldn't argue you out of it. Others will find they want more. If so, the usual route is to lengthen one or two sessions a week and leave the rest at ten. The NHS points beginners who'd like to run towards its Couch to 5K plan, which builds up over nine weeks. Keep the floor whatever you add. A more ambitious plan only means there's more that can be missed, and the ten-minute floor covers you when it is.

When the problem is something else. If you can't face any exercise at all, and that comes with weeks of low mood, poor sleep and loss of interest in things, the obstacle may be depression and not the threshold. Please see a GP. And as the preface said, if your trouble is feeling driven to exercise too much, this book's advice isn't meant for you, and a GP or the charity Beat is the place to go.