I often get asked: you can run during pregnancy? Is that safe?
The short answer is: maybe
The general rule of thumb for exercising when pregnant is to continue exercising as you were prior to conception—of course, modifying for how you feel, managing heart rate (to a degree) and being more cautious are important factors. For example, if you were an avid runner, you can continue to run, you just need to be mindful of not pushing too hard (super heavy breathing, wheezing, etc.) and always listening to your body. Higher progesterone also causes your joints to become more flexible over time, which can lead to injury if you aren’t cautious.
The outdated rule of thumb of never letting your heart rate surpass 140 has been debunked—it is more important to be able to chat/manage your training without discomfort, pain or being completely exhausted afterward. Heart rate varies dramatically from person to person and especially when pregnant; it is much wiser to measure how you feel. In fact, continuing training and exercising has been shown to improve postpartum recovery rates, improve mental health postpartum, maintain muscular and skeletal strength and support your body’s transition post pregnancy.
Some articles to glance over: