Last week, I described how our busy lives - especially the hours spent in front of computer screens - were depriving us of the exercise we need to keep our bodies functioning well. It's slowly dawned on health experts that the greatest disaster the developed world has brought on itself may well be the forced inactivity our high-tech lives demand. We're so good at improving how we work we've taken the 'manual' out of labour. A generation ago, most people got more than enough exercise by working. Even the elite had to climb stairs now and then. Obesity was a sign of wealth, not - as it is today - a sign of poverty. The problem is getting worse, and will take a long time to reverse. So what can we do? Firstly, recognise that everyone needs to get at least 30 minutes - and, preferably, an hour's - exercise (moderate to intense) every day. In February last year, a Department of Health survey found that only 35 per cent of those questioned had done 10 minutes or more 'moderate physical activities during the preceding seven days'. Secondly, find ways to get exercise into your day. Those who can control their schedules may be able to play sport or establish cardio-fitness routines. How can the rest of us make it happen? The easiest way is to walk more. If you can avoid driving to work, do so. If you take half an hour to walk to work and half an hour to walk home, you've already done a decent hour's workout. If you have children and the school is nearby, walk them there. You're doing them good by getting them into the habit of exercise early. If, like me, you're always behind schedule and don't have half an hour to spare on your way to work, take the stairs when you get there. Not once, but whenever you can. It will improve your circulation, as well as heart and lung function, strengthen bones and muscles, boost the immune system and help shed fat. However, getting onto the stairs can be hard because building managers seem to have an aversion to letting people use them. How about becoming an exercise activist? Demand the stairs be made available. If the building management ignores you, why not take the stairs to the bottom floor and open that fire-alarmed door? Lastly, all of us need to get a bit political about our exercise needs. There could be some beautiful walks along the harbour front if there wasn't a property developer mindset in our administration. Now is the time to get involved in this debate.