Exercise in pregnancy is great for most mums-to-be, helping to keep you supple, fit and in good shape for the coming birth, and it's good for your baby too. But while your body isn't so fragile during pregnancy that you need to stop exercising, it is true that your body and the demands on it have changed, and will continue to change over the nine months. So you will need to take these changes into account and accept that you most probably won't be able to work out to the same intensity as your pre-pregnancy days. To exercise safely in pregnancy you should first check with your doctor or midwife that an exercise regime is suitable for your individual pregnancy. Once you are given the green light to exercise, you need to be aware of your limits and stick within them, listening to your body and watching out for these signs that you may be overdoing it.

  • Your heart is racing - Your heart generally has to work harder when your pregnant, so you may find that your heart starts to race far more easily than in your pre-pregnancy days. There's no hard and fast rule as to what a safe heart rate is for pregnancy exercise, as everyone has a different resting heart rate. If you are the sporty type who uses a heart-rate monitor as a matter of course, then you'll already know when you're exceeding moderate exercise. For everyone else, if you feel your heart racing then it's a sign that you should lower the intensity of your exercise.
  • You feel hot / warm - It's normal to become warmer when you exercise, but you want to avoid feeling hot, which is a sign that your body is overtaxed and over-heating. It's particularly important to avoid overheating during pregnancy, as this could affect your baby's development: Overheating in early pregnancy has been associated with an increased incidence of neural tube defects such as spina bifida, and with low birth weight in later pregnancy. When you begin to feel warm you probably need to remove a layer to feel comfortable again and help prevent over-heating, but if you get to the stage that you feel hot then you need to reduce the intensity of the exercise sufficiently for you to be able to cool down quickly again, or take a break until you have cooled down.
  • You feel short of breath - Being short of breath is an even more reliable indicator than your heart-rate that you are over-exerting yourself. During pregnancy you should exercise at a level where you can hold a light conversation while you workout - if you reach the point of breathlessness then neither you or your baby will be getting enough oxygen. If you find you don't have enough puff to speak then scale back the intensity of the exercise and if you find yourself short of breath then stop right away and take a breather.
  • You feel fatigued / weak - Pregnancy is not the time when you want to push yourself to exhaustion, if your muscles are tiring or weak then it's time to stop.
  • You feel dizzy - If you get to the stage where you feel dizzy when exercising it, then this is a sign that you have already overdone it, whether you're pregnant or not. It's vital that you stop exercising immediately if you feel dizzy.
  • You develop a headache - Developing a headache during exercise is a sure sign that you're exercising at too high an intensity, you should stop exercising straight away.
  • You feel nauseous - Feeling nauseous usually occurs after you've ignored other warning signs such as becoming very hot, experiencing shortness of breath and headaches. If you feel nauseous then stop exercising immediately.
  • You have chest pains - If you have chest pains or a feeling of tightness in your chest you should stop exercising right away.
  • Uterine contractions or vaginal bleeding - If you experience uterine contractions or vaginal bleeding during or after exercising you should stop the exercise immediately and consult your doctor before continuing with your exercise programme. Experiencing these doesn't necessarily mean that you will have to give up exercise for the remainder of your pregnancy, but you certainly need your doctor's advice about what level of exercise is suitable in your circumstances.

Women who are frequent exercisers may find that they can continue pretty much as normal in the first trimester, albeit foregoing exercise with a high risk of contact or falling, for obvious reasons. However, the first trimester can, even from the first weeks of pregnancy, be a surprising drain on your system as hormones fly and the most crucial developmental work gets underway. Even the fittest of mums-to-be may find that they simply don't feel up to anything other than very gentle exercise at this stage, or that they become breathless remarkably quickly. If this happens to you then just adjust and go with the flow, the most important use of your energy right now is making that baby.

As you get your energy back in the second trimester you also begin to put on weight, which will affect what exercise you find comfortable - much will depend on how quickly, and how, you put on weight, as well as on your general fitness level. By the third trimester most pregnant women will want to stick to low-impact exercise, such as walking, pregnancy yoga and swimming, though there are some fitness queens who will regularly run up to the last. Whatever kind of exercise you are doing, at whatever stage of pregnancy, be alert for these signs that you may be pushing your body too hard, and make sure you adjust your exercise accordingly. You can find out more about how suitable exercise may change from trimester to trimester here.

Pointers for exercising safely in pregnancy

  • Keep hydrated. You need to take on plenty of water before, during and after exercise. If you feel thirsty you're already dehydrated.
  • Avoid exercising in hot, humid conditions. If it's a very hot day then exercise in the morning or evening when it's cooler
  • Avoid exercising at very high altitude.
  • Stretch but don't overstretch. While it's important to warm up your muscles before exercise, during pregnancy you become more flexible as your body changes for the growing uterus and in preparation for childbirth, so it's easier to accidentally overstretch and pull something: Be aware of your limits and keep within them.
  • Wear layers of breathable clothing that you can adjust to prevent yourself overheating.
  • Avoid sports which are likely to result in contact or falls.