Brain Rules for Baby (Updated and Expanded). John Medina
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through the “pushing phase” of labor than if you are fit. Not surprisingly, fit women perceive this stage as being far less painful.
Because the pushing phase is shorter, babies also are less likely to experience brain damage from oxygen deprivation. If you are afraid of labor, you owe it to yourself to become as fit as possible going into it. And the reasons are argued purely from the Serengeti.
Exercise buffers against stress
Fit mothers also tend to give birth to smarter babies than obese mothers do. There are two reasons for this. One may have to do with the direct effects of exercise—especially aerobic exercise—on a baby’s developing brain. This notion needs more research. More powerful are the data linking aerobic exercise and stress reduction.
Certain types of exercise actually buffer a pregnant woman against the negative influence of stress. Remember those toxic glucocorticoids, the ones that invade neural tissue and cause brain damage? Aerobic exercise elevates a molecule in your brain that can specifically block the toxic effects of those nasty glucocorticoids. This heroic molecule is termed brain-derived neurotrophic factor. More BDNF means less stress, which means fewer glucocorticoids in your womb, which means better baby brain development.
It may sound strange to say, but a fit mom has a much better chance of having a smart baby—or at least one best able to mobilize his or her IQ—than an unfit mom.
Too strenuous, and baby overheats
As usual, though, there’s a balance. A baby can feel and react to the mother’s motion. When her heart rate goes up, so does baby’s. When mom’s breathing rate increases, so does baby’s. But only if the exercise is moderate. During strenuous exercise, especially in the later stages of pregnancy, the baby’s heart rate and breathing begin to decline. The concern is that overdoing it might increase the temperature of the womb or restrict baby’s access to oxygen. As ever, your pediatrician can provide guidance about the amount of exercise you should be doing in these later stages. Your oxygen reserve levels are pretty low by the third trimester, so it’s a good time to wind down strenuous activities in preparation for labor. Swimming is one of the best forms of exercise in later stages; the water helps transfer excess heat away from the womb.
What is the proper balance? Four words: moderate, regular aerobic exercise. For most women, that means keeping your heart rate below 70 percent of its maximal rate (which is 220 beats per minute minus your age), then slowing things down as the due date approaches. But you should exercise. As long as you don’t have obstetric or other medical complications, the American College of Obstetricians recommends 30 minutes or more of moderate exercise per day.
Good advice, even though we are not wildebeests.
Every little bit counts
Maybe you’re not in the habit of exercising every day. Maybe you’re feeling guilty enough already for drinking that second cup of coffee while pregnant. If so, perhaps you will appreciate some reassurance from the research world: As a species, Homo sapiens have been successfully making babies for 250,000 years. We did very well without all this fancy knowledge, thank you, and with such success that we conquered the world. Your best intentions—Morse code belly tapping notwithstanding—will go a long way toward creating a great environment for your developing baby.
Key points
• In the first half of pregnancy, babies want to be left alone.
• Don’t waste your money on products claiming to improve a preborn baby’s IQ, temperament, or personality. None of them have been proved to work.
• In the second half of pregnancy, babies begin to perceive and process a great deal of sensory information. They can even smell the perfume you wear.
• Brain boosters at this stage: gaining the proper weight, eating a balanced diet, exercising moderately, and reducing stress.
brain rule
Start with empathy
relationship
I remember feeling almost completely overwhelmed when we brought our firstborn son, Joshua, home from the hospital. We placed our new baby in the car seat for the first time, praying that we were buckling him in correctly. I drove home from the hospital at a snail’s pace—miraculous, for me. My wife was in the backseat, just to keep an eye on things. So far, so good.
When the little guy entered our house, his tiny face suddenly corrugated into annoyance. He started screaming. We changed his diaper. Still he screamed. My wife fed him. He took one or two gulps, then resumed screaming, tried to wiggle out of my wife’s arms, tried to get away. This didn’t happen in the hospital. Were we doing something wrong? I held him. My wife held him. Eventually, he calmed down. Then he seemed to go to sleep. We were so relieved. “We can do this,” we kept telling ourselves. It was late, and we decided to follow his lead. No sooner did our heads hit the pillow than Joshua started crying again. My wife got up and fed him, then handed Josh to me. I burped him, changed him, laid him back down. He was calm and settled, and we went back to bed. I didn’t even get to feel the warmth of the sheet before the crying and screaming resumed. My wife was exhausted, recovering from a 21-hour labor, in no shape to help. I got up, held the baby, then set him back into his crib. He calmed down. Success! I crept back to bed. I got only as far as the pillow before the crying began again. I tucked my head under the blankets, hoping it would stop. It didn’t. What was I supposed to do?
This bewildering routine, and my reactions to them, recurred day after day. I had deep feelings for my son—always will—but I wondered at the time what ever made me decide to have a baby. I had no idea that something so wonderful was also going to be so hard. I learned a difficult but important lesson: Once a kid comes into the world, the calculus of daily living coughs up new equations. I am good at math, but I was no good at this. I had no idea how to solve these problems.
For most first-time moms and dads, the first shock is the overwhelmingly relentless nature of this new social contract. The baby takes. The parent gives. End of story. What startles many couples is the excruciating toll it can take on their quality of life—especially their marriages. The baby cries, the baby sleeps, the baby vomits, gets held, needs changing, must be fed, all before 4:00 a.m. Then you have to go to work. Or your spouse does. This is repeated day after day after ad nauseam day. Parents want just one square inch of silence, one small second to themselves, and they routinely get neither. You can’t even go to the bathroom when you want. You’re sleep deprived, you’ve lost friends, your household chores just tripled, your sex life is nonexistent, and you barely have the energy to ask about each other’s day.
Is it any surprise that a couple’s relationship suffers?
It’s rarely talked about, but it’s a fact: Couples’ hostile interactions sharply increase in baby’s first year. Sometimes the baby brings a hormone-soaked honeymoon period. (One couple I know constantly quoted Tagore to each other: “Every child comes with the message that God is not yet discouraged of man!”) Even then, things quickly deteriorate. The hostility can be so severe that, in some marriages, having a baby is actually a risk factor for divorce.
Why do I bring this up in a book about baby brain development? Because it has serious consequences for the baby’s brain. We learned in the Pregnancy chapter how exquisitely sensitive a baby in the womb is to outside stimuli. Once baby leaves his comfortable, watery incubator, his brain becomes even more vulnerable. Sustained exposure to hostility can erode a baby’s IQ and ability to handle stress, sometimes dramatically. An infant’s need for caregiver stability is so strong, he will rewire his developing nervous system depending upon the turbulence