The absolute minimum for a fitness improvement in a fairly unfit person is approximately one hour a week of ‘structured’ exercise, plus as much ‘building extra activity into your daily routine’ as you can.
Unless the fitness tests showed you to be ‘unevenly’ fit, you should split that hour of structured exercise into half an hour of aerobic activity and half an hour of strength/tone and stretch activity. And you should split each of those half hours up as evenly throughout the week as you can (e.g., three ten-minute sessions of strength/tone and stretch and two fifteen-minute or three ten-minute sessions of aerobics).
Even with just one hour’s exercise a week, as long as you keep trying to improve (i.e., in the case of aerobic activity, going further or more quickly, or in the case of strength/tone and stretch, doing the harder exercises or doing the movements better) you will see a gradual build-up of all-round fitness.
But obviously if you can find more time, then so much the better. The majority of fitness experts agree that three twenty-minute aerobic sessions a week are ideal to improve aerobic fitness. So if you can find ninety minutes a week, you could do three twenty-minute aerobic sessions and three ten-minute strength/tone and stretch sessions, or three aerobic sessions and one thirty-minute strength/tone and stretch class, perhaps. You work out a program that suits you – and remember, you don’t have to do exactly the same every week.
In fact, walking is the ideal aerobic activity for most people (ten minutes three times a week, building up to thirty minutes three times a week); and 7-minute workout is sufficient for most people to improve strength/tone and suppleness (ten minutes a day three times a week, building up to twenty minutes three times a week). But we would rather you made the choice – and you can take control of your own activity program, I promise you!