When does exercise become too much during pregnancy?
There are many expectant mothers who write to me asking me how much exercise can be done during pregnancy. We have already partially answered with this article by our Midwife Sara Notarantonio: How much sport can you do during pregnancy?
Here instead we will try to explain when physical exercise becomes excessive and should be avoided in order not to create complications.
There is now a large consensus among experts who share the idea that a minimum dose of moderate exercise during pregnancy can only be good for you. The problem lies in understanding when exercise feels too much or too heavy.
A study published in Medicine & Science in Sports & Exercise analyzed 62 women who were all non-practicing when their pregnancy began. At 12-14 weeks gestation half of them were assigned to a supervised exercise program which included 4 sessions per week each lasting 45-60 minutes. All continued until 36 weeks. Exercises included step aerobics, hilly terrain and circuit walking, and alternating weight training.
Here is the weekly program to which the 31 pregnant women were subjected:
DAY 1: Aerobic phase
DAY 2: Group walk on hilly terrain
DAY 3: Alternate circuits of 1 to 10 minutes of cardio (treadmill, stationary bike) with 20 reps of strength exercises on a weight machine (upper body, lower body, core), followed by five minutes of stretching
DAY 4: individual brisk walk
The exercises were performed at “moderate intensity” (12 to 14 on a scale with 20 being the maximum).
This group gained aerobic capacity and muscle strength over time. Only two women underwent a caesarean section versus 10 in the control group who didn’t follow the exercise program. They also had a much faster postpartum recovery. No differences were recorded in the length of pregnancy or in the size of the baby at birth.
So if it is clear that moderate exercise is good during pregnancy, it remains to be established when it becomes excessive and / or dangerous
How should sportswomen and women used to hard workouts behave during pregnancy? can they continue to do the exercises they used to do or should they stop or cut back drastically?
Until 1994, ACOG (American Congress of Obstetricians and Gynecologists) guidelines recommended that pregnant women avoid exceeding heart rates of 140 beats per minute. This restriction has long since been dropped, but the question remains:
Is there an intensity of exercise beyond which the health of the fetus could be compromised?
A recent Norwegian study recruited six female Olympic endurance athletes: among them 21 Olympic and world championship medalists.
They were subjected to a series of intense workouts at near maximum effort between 23 and 29 weeks of pregnancy.
While most diagnostic signs remained normal, the researchers picked up a potential danger signal in two of the women at the highest exercise intensities: for a couple of minutes after completing the exercise, fetal heart rate and blood flow through the umbilical cord is slowed down and then quickly returns to normal without adverse consequences.
Another new study, by Dr. Linda Szymanski and Dr. Andrew of Johns Hopkins University in Baltimore, gathered similar information in a study of 45 women who underwent a treadmill test between 28 and 32 weeks of pregnancy. In that study, five of 15 women who were classified as “most active” before pregnancy had a brief dip in fetal heart rate and then returned to normal within minutes. In both studies, all women gave birth without complications.
All of the women who experienced symptoms were exercising above 90 percent of their maximum heart rate, which suggests setting a target heart rate, on the other hand, two-thirds of the women who reached that threshold showed no sign of suffering.
Until more data becomes available , the study authors recommend avoiding extremely strenuous exercise, stressing the importance of listening to your body and stopping right away if you feel unwell. This is difficult for many athletes who generally adopt the philosophy that if you don’t suffer you won’t go through with it and you won’t win. But this is something to forget during pregnancy, to put in the drawer and take back when the baby is born.
For “normal” women like me who exercise occasionally, the point remains that it is important to stay active even during pregnancy. And this also applies to those who had a sedentary view until the moment they discovered the positive test. Pregnancy is the ideal time to introduce a healthy lifestyle and pregnant women generally have a great motivation to do so, which is to bring a healthy baby into the world.
Kathryn Barlow is an OB/GYN doctor, which is the medical specialty that deals with the care of women's reproductive health, including pregnancy and childbirth.
Obstetricians provide care to women during pregnancy, labor, and delivery, while gynecologists focus on the health of the female reproductive system, including the ovaries, uterus, vagina, and breasts. OB/GYN doctors are trained to provide medical and surgical care for a wide range of conditions related to women's reproductive health.