We're increasingly living in a world where physical activity has stopped being a day-to-day part of our lives. We have domestic appliances to wash and dry for us and cars to get us around, and with the decline in manual labour many of us spend our working day sitting at desks.
When we get home, we think nothing of spending the evening sitting or even lying down in front of the TV. If that sounds like your routine, then it's important to remember any exercise at all is better than none.
Many people's views on sport and exercise were formed during school PE lessons – endless laps of a muddy field, or standing around shivering in T-shirt and shorts, hoping the ball didn't come near you. Most of us have seen film of people running a marathon who look ready to keel over.
Not surprising then that many people regard exercise as something miserable that has to be very, very hard to do you any good. It doesn't.
In fact, there's a well-established theory that mild to moderate physical activity is, for most people, the best way to better health. Apart from anything else, unless you do something you enjoy – or can at least put up with – you won't stick at it. Similarly, if you start off doing too much too soon, you'll get fed up and stop, get injured or even make yourself ill.
So what's the right amount of exercise to get fit and healthy without injuring yourself in the process?
Strenuous, moderate or mild?
The intensity at which you workout can be described as strenuous, moderate or mild. What constitutes a strenuous, moderate or mild exercise workload for you will depend on your current fitness.
If you're an Olympic 10,000m runner, jogging one mile in nine minutes would count as mild activity. For most people, though, it would be strenuous, if not impossible. Experts recommend that for purposes of general health, mild to moderate levels of physical activity are all that's required.
For many of us, this means brisk or purposeful walking, or the equivalent level of effort in another activity. Again, what brisk means will depend on your current state of health or fitness. It's a pace at which you feel you're making good progress while still being able to hold a conversation.
As a rule of thumb, exercise of moderate intensity will make you a little warm or sweaty, and slightly out of breath, but no more than that.
Recommended activity levels
According to the government, only 37 per cent of men and 24 per cent of women take enough exercise to get any benefit from it. To avoid obesity, heart disease and other life-limiting conditions, the chief medical officer (the government's top doctor) recommends the following:
- Adults should do a minimum of 30 minutes moderate-intensity physical activity, five days a week.
- You don't have to do the whole 30 minutes in one go. Your half-hour could be made up of three ten-minute bursts of activity spread through the day, if you prefer.
- The activity can be a 'lifestyle activity' (in other words, walking to the shops or taking the dog out) or structured exercise or sport, or a combination of these. But it does need to be of at least moderate intensity.
- People who are at specific risk from obesity, or who need to manage their weight because of a medical condition, need 45-60 minutes of exercise at least five times a week.
- For bone health, activities that produce high physical stresses on the bones are necessary.
These recommendations also apply to older adults, assuming they're healthy and mobile enough to manage them.
In fact, older people should take particular care to retain their mobility through daily activity. Specific activities to improve strength, coordination and balance are particularly beneficial for older people.
Safety first - avoiding illness and injury
Remember you're taking up exercise to improve your health, not to make yourself ill or injured. Bear the following in mind:
- Start slowly. If you haven't done much activity for some time, it's important to build up to the recommended activity level over a few weeks. This might mean starting with a walk of just five minutes.
- If you're not sure how hard you can work because of any health problems you may have, talk to your GP or practice nurse for help and advice. You shouldn't assume because you have, say, a heart condition or a bad back that you can't exercise. In fact, there are many conditions for which certain exercises are positively beneficial. But it may be that you need to rule out certain activities, or build up more gradually than other people – so get medical advice first.
- Pregnant women should also take medical advice about exercising. Exercising during pregnancy can be excellent for posture, and strengthening your abdominal muscles and pelvic floor, but there are also signs that mean you should consult a doctor first, such as bleeding, headaches or nausea, or if you have pregnancy-induced high blood pressure, or have had more than one miscarriage, for example.
- Eat sensibly. Often when we talk about a sensible diet, we mean eating a little less, but once you start exercising there's also the danger of eating too little and having too little energy. We all need a healthy, balanced diet that contains the right vitamins, minerals, carbohydrates and proteins, but if you're exercising you're burning energy so you need to make sure you have enough 'fuel'. Again, if you're unsure about the best diet for you, talk to your GP.
- Don't get dehydrated. During exercise our bodies get hot, and our main way of cooling down is to sweat, which means we lose fluid. On average, we lose one litre of fluid for every hour we exercise. The longer and harder you work, the more you'll lose and there's no way to be exact about how much you should drink. Try to drink 300ml to 500ml of fluid in the 15 minutes before your workout, then about 150ml to 250ml every 15 minutes during exercise. For moderate exercise of about half an hour, water is fine – for longer, more strenuous workouts, specialist sports drinks may be better.
- Warm up and stretch. Again, this is more important the longer and harder your planned exercise is, but it's a good habit to get into if you want to prevent injuries, such as pulled muscles.