Age doesn't necessarily dictate what we're capable of doing - I've seen 80-year-olds able to increase their muscle mass.

I have a friend in the US who's a personal trainer who was recently asked to work with Barbra Streisand. ‘We were talking about how to structure her exercise program,' Kathy Kaehler explains. ‘It must've started sounding all too hard for her as she stopped me and said: "You know I'm 66?" I just said: "Yeah, and?"

‘I never look at the women I work with and base workouts on their age,' she adds.

‘There are age-related health facts, such as menopause and osteoporosis, but a 60-year-old still needs several heart-pounding workouts a week.'

In your 20s 

This is the best age for health and fitness. Bone density is strongest between the ages of 25 to 35, while muscle mass peaks at 25. Unfortunately, fast food and alcohol can
also seem more attractive than exercise.

• Recommendation

At least 30 minutes of exercise a day. Three cardio sessions a week including aggressive weight-bearing activities, such as running, body combat classes or skipping rope.

In your 30s 

Welcome to the decade of being time-poor, thanks to marriage, kids and a career. Fitting in exercise can be hard. Watch for snacking on the run. Muscle mass will also drop by two per cent a year if you lead a sedentary lifestyle.

• Recommendation

Thirty minutes a day, and increase weight and resistance training to two hours per week. Deck out a corner of the house with dumbbells, a floor mat, fitball, resistance band and a ‘how to' DVD. Do aerobic activities on alternate days.

In your 40s

A higher income means dining out more often, and routines may be forged, such as nightly chocolate in front of the TV instead of exercise. Menopause can be to blame, but so can the weight gain that's been creeping on all decade.

• Recommendation

Time to huff and puff again - aerobic exercise is vital for keeping the fat at bay. Power walking and swimming are ideal. Try to mix it up with weights, and introduce yoga or Pilates for flexibility.

In your 50s 

A fall in oestrogen levels after menopause makes it hard for women to hang on to muscle. Focus on a diet rich in protein - the building blocks for muscles - such as eggs, fish and lean red meat.

• Recommendation

Aerobic exercise is important but aim for low- impact sports, such as cycling and swimming. Strength training will ward off osteoporosis, while tai chi is great for body awareness.

Tip: Regardless of age, dietitian Susie Burrell says there are five items to keep out of your supermarket trolley: instant noodles, canned meat, jelly, fruit twists and cordial.