While we all know it’s important to exercise regularly,how much you should be doing – and what type – changes as you age.
Here, with the help of leading sports scientists and other experts, we explain what happens to your body at each key stage, and the workouts appropriate for that time.
At this age children are growing fast and are simply learning to support their own body weight and their muscles.
A study at the University of Maryland’s Department of Kinesiology showed that crawling and walking around are the best way for babies and toddlers ‘to use their large muscle groups in activity’.
HOW MUCH: No more than 15 minutes of ‘structured activity’, such as a game of football, throwing a ball or swimming every day. All other activity should be made up from general play.
TYPE OF EXERCISE: ‘Young humans have an innate desire to climb, run, jump and move,’ says Professor Craig Williams, co-director of the Children’s Health and Exercise Research Centre at the University of Exeter. ‘Encouraging and allowing them to do that is the best step you can take to steer them towards lifelong fitness.’
Organised toddler workouts, such as toddler aerobics, baby yoga and mini football, are widely available but unnecessary. ‘Fitness is actually an adult concept,’ says Dr Eric Small, a leading American pediatrician.
‘Young bodies are not capable of the sustained activity required to improve cardiovascular health, strength and flexibility.’
Psychologically, introducing too much formal activity could be counterproductive. A child that is sent to football or aerobics at three or four is more likely to be bored of them by the time they are ten.
A time of hormonal changes, rapid growth and development – during adolescence, boys can grow by as much as 31/2in (9cm) taller a year; girls at just more than 3in (8cm).
Girls start earlier, growing fastest when 12 and 13 but ending their growth spurt earlier at 18, while boys need another two years to finish growing aged 20. Making exercise a habit not only enhances natural growth, but helps to protect against obesity in adulthood.
HOW MUCH: All five to 18-year-olds should do a minimum of an hour of moderate intensity activity (that leaves them out of breath but not exhausted) a day, according to Department of Health guidelines.
The more activity at this age, the better, says Professor Ken Fox, a physiologist at the Department of Health and Exercise Science at the University of Bristol – ideally, children should actually do another hour of active play ( anything that means they are not sitting down) on top of these guidelines.
TYPE OF EXERCISE: From ages five to ten the bones are not fully developed, so intense exercise (such as weight training) is not suitable. However, moderate activity – running, swimming, cycling and games – enhances normal growth and wards off childhood obesity. Buy them sporty toys: skipping ropes, mini-basketball nets, pogo sticks, baseball or cricket sets.
As well as cycling and running, ten to 18-year-olds should be encouraged to do competitive sports. School sport is important. The government has set targets to increase participation in sport by five to 16-year-olds to a minimum of two hours per week.
If your child’s school is not meeting this, consider extra-curricular activities. And set a good example. Studies have shown that the more active the parents, the more active their children.
This is the easiest age to maintain a healthy weight because your metabolic rate is at its most efficient, burning more calories both at rest and during physical activity.
However, a failure to be active can result in a steady weight gain that is more difficult to lose as you get older. Bone density peaks between the ages of 25-35 and muscle mass is at its highest around 25, which means you should find it easier at this age than any other to stay toned and lean.
HOW MUCH: At least 30 minutes of moderate activity five or more days a week, according to the government’s chief medical officer.
But that is a minimum to stay healthy. Ideally, you should try to include at least three one-hour sessions of aerobic activity (which makes your heart and lungs work harder) a week.
You should also include a couple of weight-bearing and flexibility workouts to maintain bone density. Weight bearing involves moving your body on a surface, such as when running, power-walking or in an aerobics class; this puts stress on your bones and tendons helping build their strength.
Activities such as rowing, swimming and cycling are not weight-bearing forms of exercise.
TYPE OF EXERCISE: Good forms of aerobic activity include running, swimming, brisk walking and cycling. For flexibility, try Pilates or yoga.
Short of time? Try skipping, which works the cardiovascular system, strengthens bones and muscles and burns up to 110 calories in just ten minutes. Build up to as fast a pace as you can.
If you are inactive you lose muscle mass at a rate of one to two per cent a year from around 30 onwards and need, on average, 125 calories less per day at 35 than you did when you were 25.
Both sexes produce less growth hormone from the pituitary gland during this decade, which further contributes to muscle and bone deterioration.
Wear and tear on the joints is more pronounced, and recovery time from injury takes longer.
HOW MUCH: A combined weekly total of two to four hours of weight and strength training. This can involve weight training at the gym or improvising at home with resistance aids such as stretchy bands, lifting cans of beans – even digging the garden. Plus one hour of stretching and flexibility a week (such as yoga).
TYPE OF EXERCISE: ‘A combination of weight training and aerobic activity is not only the best way to stay slim, but also to increase bone density and strength,’ says Louise Sutton, principal lecturer in health and exercise science at Leeds Metropolitan University.
Try an indoor boxercise class or outdoor circuit – classes such as British Military Fitness are held in many UK parks. Or make up your own exercise circuit using park benches, trees and footpaths as your equipment.
Bones are deteriorating faster than they are forming – women lose one per cent of bone mass a year from now until the menopause. In women, the menopause is likely to occur during the late 40s to early 50s, and consequent hormonal changes can cause weight gain of up to a pound a year until the menopause is over.
Hormonal changes at around the age of 50 – testosterone and dehydroepiandrosterone (or DHEA, a hormone that helps to control metabolism and energy use) begin to decline – make keeping slim more difficult. Regular exercise routine helps to slow these changes.
HOW MUCH: A combined weekly total of two to four hours of weight or strength training and cardiovascular activity. One hour of stretching and flexibility a week.
TYPE OF EXERCISE: Aerobic exercise is vital for burning fat – try power walking. Invest in a pedometer and work up to 16,000 steps a day, trying to walk as fast as possible. If your joints are starting to get painful, switch to non-weight-bearing aerobic activities, such as swimming or cycling.
However, weight training is vital. Studies have shown that doing high intensity weight lifting (i.e. lifting 70 per cent of the maximum weight you think you can manage) a couple of times a week can offset the loss of muscle mass during this decade.
If you belong to a gym, ask an instructor to devise a progressive weights programme. At home, invest in a set of mini-weights or improvise with bottles filled with sand or water.
Beyond the age of 50, muscle mass is lost at a rate of one fifth of a pound a year. This loss affects both sexes but is more pronounced in men, who often experience a much sharper decline in strength. Often the muscle lost is replaced by fat, hence the dreaded middle-age spread.
Female fat distribution changes after the menopause often causing women to become an ‘apple’ shape as weight shifts to the waistline. This signals that someone has more visceral fat (around the organs), the type that promotes heart disease and inhibits glucose tolerance.
To check whether you are at risk, place a tape measure around your middle. A measurement of more than 80cm (32in) for women and over 94cm (37in) for men means you are at increased risk of heart disease and diabetes. Over 88cm (35in) for women and 102cm (40in) for men puts you at the highest risk of these conditions.
HOW MUCH: A combined weekly total of two to four hours of strength or weight training and cardiovascular activity. One hour of stretching and flexibility a week.
TYPE OF EXERCISE: Sports that challenge your speed and endurance, such as badminton, tennis and football, provide all the elements of fitness you need to address in one session.
Lunges (preferably with hand weights) and leg lifts in the weight room are great for strengthening the quadriceps muscles in the thigh, helping avoid joint injuries and osteoarthritis.
‘As you get older, you lose water content from the body’s structures, including cartilage that protects the joints,’ says Claire Small of the Chartered Society of Physiotherapists. ‘Tissues become weaker, which means injuries happen more easily.’
Osteoarthritis, a degenerative condition caused when the cartilage protecting joints gradually wears away leaving bones to scrape directly against one another, is more common from age 60 onwards.
By age 70-80, the number of fibres in a muscle can be almost half the amount in a 50-year-old, meaning your ability to sprint and compete in explosive sports and activities will decline.
Both men and women will also be shorter. By 80, men are an average two inches shorter and women three inches shorter than they were in their 30s because of a decrease in bone mass.
Studies have shown that older people who exercise are less prone to falls, more agile and less likely to suffer killer diseases such as heart disease, cancer and diabetes.
HOW MUCH: If you haven’t exercised for a while, aim for 30 minutes of moderate activity, five days a week.
TYPE OF EXERCISE: Swimming is a great form of aerobic exercise if you have painful joints or arthritis – the water acts as a giant, protective cushion for the body.
Different strokes work different muscle groups so try to combine front crawl, breast stroke, back stroke and butterfly.
Weight-training or resistance activities such as Pilates are advisable for strengthening bones and warding off osteoporosis.
Classes at gyms are a great way of making sure you don’t overdo it. T’ai chi is also great for improving balance problems common with old age.