Reassurance about running in pregnancy

I will start by telling you why you dont need to worry about your baby being deprived of important blood flow whilst you are working out during pregnancy then go on to give you some practical advice about running when you are expecting.

Fundamental changes to your blood flow during pregnancy exercise

Before I get on to talking about running in pregnancy in particular I just want to share with you what happens in your body when you exercise:

During exercise your blood flow changes as follows:

  • Increased blood flow to the heart, working muscles, skin and adrenal glands
  • Decreased blood flow to the kidneys, digestive & reproductive systems

During pregnancy this is fundamentally different:

  • Increased blood flow to the heart, reproductive system, skin and kidneys
  • Decreased blood flow to the working muscles

This means that your body is always going to direct blood to your baby first so they are getting a plentiful supply of oxygen and nutrients. This shift is likely to mean that as your pregnancy progresses you may find your muscles fatigue more quickly. Along with the other changes going on to your cardiovascular system (including higher blood volume, faster breathing rate, higher resting heart rate) this is why you must adapt your workouts as your pregnancy moves along and never ignore any signs that you are pushing yourself too hard. This time is all about fitness maintenance for health, not breaking world records!


This brings me on nicely to running. One of the most frequent things I hear is that it is not safe to run during pregnancy. However, there is no one-size-fits-all response to this – it largely depends on your pre-pregnancy fitness level and your running experience. As we have just learnt, our bodies will always put blood flow to our baby ahead of blood flow to our muscles, so as long as you aren’t drastically increasing your exercise your body will most likely adapt fine to continuing to run.

Running has tons of benefits. In addition to improving cardiovascular fitness and increasing bone density it can help you sleep, improve your mental health, get you out in the fresh air, boost your immune system (and complexion) and help you build lean (fat burning) muscle. Don’t forget those endorphins too – they will make you feel fab!

So what advice would I give you? Taking different levels in turn:

If you have never been a runner, do not start during pregnancy. There are plenty of other activities you can do.

If you have done a little bit of running I suggest keeping it at a moderate intensity (jogging rather than running) and doing no more than 30 minutes a couple of times a week. If you haven’t done any running for at least two months, then do another form of exercise. And if running feels at all uncomfortable then do something else.

If you are an experienced runner then there is no reason why you cannot carry on running during pregnancy. You know what your body is used to doing. Don’t try and maintain pre-pregnancy distances and times. Just choose a route that you can do comfortably and taper this as the months go by.

Few things to remember:

  • Wear a good pair of trainers and a supportive bra
  • Take care not to overheat and avoid running in very hot and humid conditions
  • Take your phone with you
  • Hydrate as you go (especially if you are out for over 45 minutes)
  • Have  a snack at least an hour before you go out and something to aid recovery afterwards
  • Don’t run up or down really steep hills and avoid rough or rocky terrain if possible
  • Remember your personal safety and take care at night time or in quiet areas
  • If you are running you need to take on extra calories from healthy foods to make sure you eating enough to support your baby’s growth
  • You may notice you get a bit more discharge when you have been running. As long as there is a normal amount and there is no blood or significant fluid leakage this is nothing to worry about. The action of running is just aiding gravity!
  • You may want to plan in some toilet breaks depending on how your bladder is coping!
  • An under-bump support may make you feel more comfortable and will also help protect your back

Here are some suggested guidelines:

During Trimester 1

Carry on as usual, as long as the intensity is not too high (i.e. intervals, sprinting), the duration isn’t too long (i.e. for most people other than competitive athletes no longer than 90 minutes) and you are not working harder than you have been used to.

During Trimester 2

Start decreasing your intensity and duration once it starts to feel as though running is becoming harder. Remember, you should comfortably be able to maintain a conversation when you are working out. Your body is changing and although you can carry on running (although for most people it should be ‘jogging’ – not too fast!) you should gradually start to adapt your workouts.

During Trimester 3

You may be able to carry on jogging if it still feels OK, but make sure you listen to your body and move on to a lower-impact activity if it doesn’t feel right. Your bump may make you feel unbalanced or you may experience pelvic aches. Some women, like marathon runners and very experienced runners may continue unhindered into the later stages of pregnancy, every one is different and we should never judge anyone else.

Remember that running will put pressure on your pelvic floor as your bump gets bigger. Cross training, power-walking, cycling and swimming are all great alternatives. If you do continue to jog then work at a comfortable intensity for a sensible duration and maybe build in some walk/jog sessions, alternating for five minutes at a time.

To sum up, if your pregnancy is low risk and you feel fine, don’t be frightened to continue running, but remember that it is a high impact activity and you may feel more comfortable switching to gentler activities later on in your pregnancy. You can always take up running again after the birth. It’s up to you – every woman is different.

You might find that carrying on with your regular runs contributes significantly to your sanity and mental wellbeing during pregnancy and have no problems at all – fantastic! Ignore anyone who tries to criticise you; we need to change the way people perceive pregnant women – start the revolution! I continued to run throughout my first pregnancy, just tapering off in the later months and I did my first marathon eight months after giving birth in four hours and 40 minutes. I love running and it makes me a better, calmer and more energetic person (yes you can be both!) for my family.

Definitely ignore anyone that tries to criticise you jogging with a bump; we need to change the way people perceive pregnant women – start the revolution! 🙂