There’s a lot of it about at the moment. It’s prompted some questions with regard to exercise and its effects during pregnancy. Should you stop? Should you keep going but change your training? If so how?

The first thing you don’t do is stop. A single line in a Canadian study into best practice for pregnant women and exercise succinctly concludes that (unless told by a Doctor otherwise) ‘All women should be encouraged to participate in aerobic and strength-conditioning exercises as part of a healthy lifestyle during their pregnancy’. As far back as the third century BC, Aristotle eluded to the difficulty endured during childbirth as a result of a sedentary maternal lifestyle. So, keep training.

As some of you will know, especially if you attend our HIIT, Cardiolates or Kettlebell classes volume and intensity are inversely related. You cannot increase both and expect better results. As volume goes up, intensity must come down and vice versa. An intensity reduction is even more critical when pregnant. So volume can stay (initially) but intensity needs to change. If you are reading this post it is likely that you are a client of ours and/or someone who participates in regular, high volume exercise (4-5 hours per week or more). The research is encouraging for you. Not only should you continue to train but you can follow your usual training schedule. During the early stages of your pregnancy there is no need to reduce the amount (volume) you train. However, you will need to concede some of your traditional training intensity. While you may see pictures of heavily pregnant women all over the internet performing high intensity Cross fit-style workouts, it is not encouraged. One study found that highly active women experienced transient foetal heart rate decelerations immediately after high intensity exercise leading researchers to conclude that pushing beyond a certain threshold intensity may compromise foetal well-being.

What is the threshold?

A minimum volume of 150 minutes of accumulated exercise each week at moderate to high intensity, that is a minimum of 60 percent of MHR (Maximum Heart Rate) and a maximum of 70-75 MHR.

What does this mean for you?

Know your max HR and calculate how many beats per minute equate to 60 and 70/75 percent of the number. Basic max HR can be determined by subtracting your age from 220. For example, a 30 year old would have a theoretical max HR of 190 BPM (Beats Per Minute). For her to achieve her pregnant training zone of 60 to 70/75 percent MHR she would need to get her heart rate to between 114 and 133/142 BPM.

How will your classes change?

Not too much. After your first trimester you will no longer perform spinal flexion (crunches) to protect the integrity of your abdominal cavity. Alternatives will include manipulation with the ring (squeezes, pelvic rotation etc), leg extensions and planks, anything that keeps your spinal neutral. You will also focus on drawing the pelvic floor up and in as well as drawing the belly button towards the spine and this carries the added bonus of preventing incontinence after your baby is born. Which is nice. Extra care will be taken when moving from a prone to standing position as the weight of the baby can press on organs and blood vessels causing a drop in blood pressure which may lead to dizziness. Other than that, aside from monitoring your intensity you will be able to train as usual with a maximum of three classes a week meeting the above guidelines.

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Vaughan, Exercises before Childbirth, Faber & Faber, London, UK, 1951.

Canadian Society for Exercise Physiology, “Canadian Physical Activity Guidelines: 2011 Scientific Statements,”

Physical Activity during Pregnancy: Impact of Applying Different Physical Activity Guidelines
Katie M. Smith and Christina G. Campbell
Sports Med. 2011 May 1;41(5):345-60. doi: 10.2165/11583930-000000000-00000.

Exercise guidelines in pregnancy: new perspectives.
Zavorsky GS1, Longo LD.

Strenuous exercise during pregnancy: is there a limit?
Szymanski LM1, Satin AJ.


Does regular exercise including pelvic floor muscle training prevent urinary and anal incontinence during pregnancy? A randomised controlled trial.
Stafne SN1, Salvesen KÅ, Romundstad PR, Torjusen IH, Mørkved S