Pregnant Women Can Exercise In Warm Weather And Have Hot Baths Without Risk, Study Finds | HuffPost Life

The studies they analysed included women at any stage of pregnancy.

Jennifer Cockerell, Press Association Health Correspondent— PA for HuffPost UK

Pregnant women can exercise in warm weather and use saunas or hot baths without risking the health of their unborn child, according to a study which contradicts current advice that women should avoid getting too hot.

The University of Exeter was involved in carrying out the research, which analysed the results of 12 studies published up to July 2017.

These reported the core temperature response of 347 pregnant women to heat stress, either through exercise or through passive heating, such as using a sauna or sitting in a hot bath.

Current advice says that pregnant women should avoid heat stress based on concerns about possible risks of exceeding a core body temperature of 39C during pregnancy. Their research, which is published online in the British Journal of Sports Medicine, found no woman exceeded the recommended core temperature limit of 39C across all studies.

Dr Ollie Jay, of the University of Sydney, who lead the study, said: “Health guidelines for pregnant women unanimously state that hot water immersion or sauna use should be restricted due to the elevated risk of maternal hyperthermia and the consequent potential impact on foetal development.

“However, our results suggest that heat stress risk is low.”

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The highest overall individual core temperature reported was 38.9C, while the highest average core temperature was 38.3C for exercise on land, 37.5C for exercise in water, 36.9C for hot water bathing and 37.6C for sauna exposure.

Based on these results, the researchers say that pregnant women can safely engage in up to 35 minutes of high intensity aerobic exercise (at 80-90% of their maximum heart rate) at air temperatures of up to 25C and 45% relative humidity.

They said they can also safely take part in aqua-aerobic exercise in water temperatures ranging from 28.8C to 33.4C for up to 45 minutes, and sit in hot baths (40C) or hot/dry saunas (70C; 15% relative humidity) for up to 20 minutes, irrespective of pregnancy stage, without reaching the recommended core temperature limit of 39C.

They argued that current guidelines do not clearly define heat stress limits and may therefore be discouraging physical activity during pregnancy, even though it could benefit both mother and child.

The studies they analysed included women at any stage of pregnancy and responses were measured according to intensity and duration of exercise as well as ambient temperature and humidity.

Some also showed a reduction in the rise in core temperature as pregnancy progressed, lending support to the theory that thermal regulation was enhanced during pregnancy.

While the underlying reason for this is unclear, the researchers suspect it may be linked to changes in body mass and surface area.

They pointed out some limitations of their review, such as the small body and varying quality of evidence, and inconsistency in study design.

They suggested more research was needed to identify safe exposure and environmental limits for pregnant women who are physically active in hotter climates, but said their results suggested that heat stress risk was low.

Before You Go

Pregnancy worries and words of comfort

I have no morning sickness! Is that bad news?(01 of10)

You might have read things about how morning sickness signifies a healthy level of pregnancy hormones – but not having morning sickness does not mean you're lacking! Although many women suffer with it (and 'suffer' really is the word), many other women do not. Some women have it one pregnancy, but not in another. Attend all your usual checks and count yourself as one of the lucky ones! (credit:Alamy )

I drank before I knew I was pregnant, I might have harmed the baby(02 of10)

This happens to many, many expectant mums, and it's unlikely to be a cause for concern at all. Mention it to your GP/midwife, and just keep off the booze now, until you can enjoy a celebratory glass of fizz when your bundle arrives. (credit:Alamy )

I'll lose the baby(03 of10)

It's estimated about one in five pregnancies ends in early miscarriage, and it's thought most of those occur simply because the foetus wasn't developing properly. It does happen, but don't let it rule your thoughts because the vast majority of pregnancies do succeed. Try not to worry and remember that once you're into the second trimester, the chances of miscarriage is dramatically reduced. (credit:Alamy )

My baby might not be 'perfect'(04 of10)

It's estimated that one in 16 babies in the UK is born with a birth defect – but this figure refers to all birth defects, and many are mild and can be treated. So it's likely your baby won't have a birth defect, and even if they do, they will be perfect in their own way – remember support is available for every eventuality. Take your folic acid and attend your antenatal screening appointments. (credit:Alamy )

I won't make it to the hospital on time(05 of10)

You might have read terrifying stories about pregnant women giving birth in car parks and taxis – but these stories make it to the news because they are extraordinary, in the literal sense of the word! It very rarely happens, and most women get plenty of warning that labour is beginning. So plan well, and all is very likely to be fine. (credit:Alamy )

I might have to have a c-section(06 of10)

If you do end up needing a c-section, you might feel disappointed – but believe us, in the moment the only thing you'll really care about is the safe delivery of your baby. It won't be the end of the world and you won't care a jot when your baby is in your arms. (credit:Alamy )

I won't be able to cope during labour(07 of10)

There is just no telling how labour will be for you, so don't worry about it now. Make your birth plan, discuss it with your partner and midwife, and go with the flow on the day (it's okay to change your mind!). There will be lots and lots of help and support at your disposal. Not to mention drugs, should you need them. (credit:Alamy )

Labour will humiliating (will I poo on the bed?!)(08 of10)

You've heard about that then? It can happen, but the doctors and midwives have seen it all – they have experienced every possible scenario. They won't be worrying about things like that, so neither should you. (credit:Alamy )

I don't know how to be a mum(09 of10)

No-one does until they become one! Every new mum feels like they're winging it in the early days. As your baby grows and you get to know them, you'll learn. Trust in the fact that just about every mother has gone through it… and survived. (credit:Alamy )

I'm worried about gaining all that weight(10 of10)

You will put on weight, yes – but it's normal and nothing to be afraid of! Much weight gain is actually down to the baby, the placenta, extra blood in your system and the retention of water. Pregnancy changes your body in myriad ways – just enjoy it, and let your body just do its thing at this special time. Remember, there's no need to 'eat for two'… but eat what you need and don't count calories. (credit:Alamy )

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