This topic makes my blood boil! I’ll try and keep my ranting to a minimum and focus on the facts.
The facts:
– In 1985 the American Congress of Obstetricians and Gynecologists (ACOG) indicated that maximum heart rate during pregnancy should not exceed 140 bpm.
– In 1994 ACOG removed the heart rate guideline…”there are
no data in humans to indicate that pregnant women should limit exercise intensity and lower target heart rate because of adverse effects.’’
– In 2002 (and reaffirmed again in 2009) ACOG stated “in the absence of either medical or obstetric complications, 30 minutes or more of moderate exercise a day on most, if not all, days of the week is recommended for pregnant women.”
Heart rate hasn’t been part of the recommendations for quite some time now and yet most doctors still throw out the old keep your HR under 140 bpm nonsense. And it makes me want to scream.
In a nutshell, ACOG states that because of the variability in a woman’s heart rate during exercise throughout pregnancy, target heart rates are an unreliable measure of intensity (source – this is a great book, by the way).
So why do doctors still give outdated advice? To cover their asses, in my opinion. Can’t say I blame them either (in a small way). Patients lie. How many times have you lied to your dentist about flossing every day? I’m sure newly pregnant women often inflate the truth about their current exercise level (or lack of) to their doctors.
I think pregnancy is a wake-up call for some women to start exercising. In this population, heart rate guidelines may be the way to go (as opposed to The Borg Scale of Perceived Exertion) and maybe that is why doctors are still using this guidance. It took me a few years after I started running to really understand what my body could handle in terms of pace and exertion.
But to tell a runner (or any other avid exerciser) to keep their heart rate under 140 bpm is ridiculous. The first time I encountered such nonsense was my reproductive endocrinologist. Although his guidelines were far more strict – 120 bpm. I told him that was a brisk walk and those guidelines were outdated. He told me those were “his guidelines”. I left the office frustrated and that prompted me to do my own research (note: I never followed any heart rate guideline, just the Borg scale).
Luckily I was released to my OB at 8 weeks and she supports my running as long as I listen to my body. I have no issues with that recommendation – I’ve been doing that for many years and it has served me well so far.
The experiment*
Matt repeatedly urged me to do a run with a HR monitor just to see. At the end of May I set out for an 8-miler, HR monitor strapped to my chest, and didn’t look at pace on my Garmin. The result? An average pace of 9:15 and my heart rate never went above 144 bpm.
I was astonished! I never train with a HR monitor and I thought for sure my heart rate would be sky high. After doing all that research the common theme was frustration at how slow your pace had to be in order to stay within 140 bpm.
Go figure.
*I have to add that this was a one-time experiment (on a cool day) and I need to do it again (ideally monthly) in order to accurately see what my range is. I would imagine my heart rate to be higher now at the same pace with (sadly) some loss of fitness.
I would love to hear your thoughts and experiences!
This is my pet peeve!! It angers me how many health professionals will tell fit women with low risk pregnancies to basically walk for no other reason than this outdated stat. And hundreds, maybe thousands of women probably don’t question it or question it but adhere to the “standard.” I’ve listened to my body just like I would, even more than I would not pregnant. I haven’t even used a heart rate monitor because it’s an unreliable indicator of effort when pregnant.
Within days of finding out I was having a baby, I started reading “Exercising Through Your Pregnancy” by Dr. James Clapp with ACTUAL , RECENT statistics. I recommend it to everyone who is pregnant or has questions about exercising in pregnancy. The benefits are amazing and I’m glad my baby will be the beneficiary.
I understand this is annoying but, in defense of the healthcare professionals, this is a highly litigious area and malpractice insurance is sky high. You’re right they play CYA…because too many people expect that they have the ability of God and can cure or save everyone and sue them when they don’t.
I agree that fit women can continue with exercise through pregnancy, however, remember that the majority of the pregnant women seen by providers are not nearly active enough (supported by the obesity rates) so you are an exception. Totally agree that your baby will benefit from the activity and am super excited to see kids with parents that will encourage and promote activity!
Also, they see so many patients that don’t know their limits and when the only encounter with the patient is in an exam room, it’s very difficult to judge if they are a balls-to-the-wall competitor or if they can use some good judgement about when to listen to their body and rest some. An experienced exerciser is usually good at this but it’s scary to give that patient the go ahead for atypical levels of activity and put your neck out there as a provider.
Sorry for the mini-rant and I sure didn’t mean to offend…just another perspective. Love reading your blog and will be excited to see how well you manage the pregnancy and postpartum period!
Very interesting! As with most things related to working out and running, I agree that listening to your body is the best way to go. I think it’s so great that your doctor supports you running!
My HR is always well into the 160’s or 170’s when I run, luckily I have had 0 desire to run since becoming pregnant (in all honesty it had weened in the few months prior as well – since I burnt myself out with halfs last year.)
I am perfectly happy to walk, or hop on the bike or elliptical in the basement at work nowadays. But even then the machines tell me I’m above 140 within minutes. And for some reason I get headaches now when I try and exercise. But LO has yet to make me sick or make me feel exhausted so I’ll take that if its the worst symptom I get.
I read and highly recommend Runner’s World: Guide to Running and Pregnancy. It was my bible when I was pregnant with Lili. http://www.amazon.com/Runners-World-Guide-Running-Pregnancy/dp/1579547478
When I got pregnant and before my first U/S appt. with my OB (at 10-weeks), I read in that book that there was no medical research that stated having to keep your heart rate under 140 and if a doctor tells you that, then you should think about finding yourself a new doctor. When I asked my OB/GYN her thoughts on keeping my heart rate under 140, she told me, “No way that’s possible and don’t worry about that — it’s not in your control and there is no medical research that has proven that if you go over 140 it will be harmful to you or baby”. I knew then, we were a match-made in heaven (and my husband absolutely LOVES her).
I ran with a girl that was pregnant when I was pregnant with Lili and she used a HR monitor. We didn’t have the same OB but she wanted to keep her HR between 140-150.
I do my runs by feel — if I feel like I need to walk, I’ll walk. If I feel a cramp, I walk. I feel like WE know our body’s best.
PS that’s great that with a 9:15 min/mi your HR was still at 144. Wow.
My OB said under 130 when I was pregnant, but I just ran on perceived effort. Now, looking back, it’s frustrating because I have actually done HR testing, and my max heart rate is actually rather high. That means that I don’t even hit aerobic exercise UNTIL my heartrate is ABOVE 140. Having one HR threshold for ALL pregnant women is like saying we should all wear the same sports bra. Utterly ridiculous.
I don’t really have anything to offer since I’ve never been pregnant but I have been surprised when I do wear a HRM that my HR doesn’t get super high at a comfortable pace. I have to push it to get to 160/170. The only time I tried to keep my HR BELOW a certain pace was during my HIM and that was impossible. I have no idea what I will or won’t do when I’m pregnant, guess I’ll have to cross that bridge when I (hopefully soon) come to it!
Interesting post. I can’t keep my HR <140 at that pace while NOT pregnant! I think I was pleased with keeping it under 160 for that pace last week. I get touchy about HR things though, because my actual max HR seems to be higher than any "formulas" indicate, and my HR still recovers to normal levels quickly so I think I'm just an anomaly. Not surprisingly though, I think my HR is pretty sensitive to how well-rested I am, hydration, outside temperature, and caffeine.