Is breastfeeding slowing me down?
To be clear, the benefits of breastfeeding for my son and me outweigh any short term negative impact on my speed. Fortunately my livelihood does not depend upon running so I am free to make that choice.
Running is a key component of my lifestyle, however, and I have lofty personal goals! I’ve been sitting on a plateau of essentially identical 5k and 10k times from 4-14 months postpartum and I’m beginning to doubt my more ambitious goals. I’m pretty confident in saying that lactation is not performance-enhancing, but how much, if at all, does it hold me back?
First, I’ve learned that testosterone levels decrease during lactation. Although T in women is significantly less than in men (30 to 95 nanograms per deciliter range versus 300 to 1,200 ng/dL), it is still an essential hormone. Unfortunately I could not find specific T levels associated with lactation (and certainly not in a population of athletes) so I can only speculate about the magnitude of effects.
But we know that testosterone is related to physical ability, energy levels, and aggression so it would follow that this decrease could tack on time to your races. In addition, testosterone may assist in coping with pain (hello marathon training!). The decreased T levels along with increased prolactin (the hormone that helps moms produce milk) are associated with a lower libido. Pepper thinks this is bad for your race times!
On the positive side, women who breastfeed have better bone density. Yes, even though you are producing calcium-rich milk, your calcium absorption is increased so a runner who has breastfed may be less likely to get stress fractures! Another bit of good news is that by inhibiting menstruation, your iron stores are conserved. The amount of iron produced in breastmilk is far less than what would be lost through monthly periods. And you’ll also miss out on all the monthly yuckiness that tags along.
I would be remiss if I didn’t mention lingering effects of pregnancy–such as increased blood volume–which can boost performance. I’ve spoken with many mothers and read anecdotes from others who report an increase in pain tolerance after labor and delivery. Many women end up running their fastest times after giving birth! I am just itching to join that club.
Some nursing moms report losing weight quickly while others believe that breastfeeding seems to make them hold on to a few extra pounds. A few pounds up may slow you down slightly, but being underweight has its own risks (including your milk supply). Personally, I am within a couple pounds of pre-pregnancy weight but my diet is whacked out! I waver erratically (often within the same day!) between a focus on high quality vegetables and protein and a severe craving for all the chocolate. I’ve also suffered dehydration from underestimating my increased fluid needs. Higher calorie and fluid needs add an additional challenge especially to marathon racing.
When JB was tiny, long runs were significantly limited due to his 2-hour interval between feedings, unless I wanted to pump an extra bottle and get through the discomfort of full boobs at the end of the run. Of course this was a very temporary inconvenience and introducing solid foods at 6 months reduced the pressure of being his exclusive source of nutrition. And–bonus!–Patrick bought me a new Garmin to celebrate the milestone!
On the other hand, a break from training, lingering pelvic or back issues, and loss of core strength will hold you back, at least temporarily. A word of advice here–don’t delay a visit to a women’s health physical therapist for an evaluation. Thyroid problems may emerge in the postpartum period. In addition, relaxin–that joint-loosening hormone–may stick with a nursing mama longer.
Finally, having a newborn causes some significant lifestyle changes regardless of whether you are breastfeeding (or whether you are the one that gave birth). Lack of sleep, an altered training schedule, use of a stroller or treadmill, and changing priorities are a few factors here. JB and his daycare buddies have shared a variety of illnesses with me that have interrupted training on several occasions. I have yet to exceed ~80% of pre-pregnancy mileage and I complete the vast majority of those miles on the treadmill. Oh–and we still don’t sleep through the night!
So even though there isn’t any hard evidence that breastfeeding is slowing me down, it’s really no surprise I’m slower right now. But I have hope that as weaning, maturation (please sleep, kiddo!), and adaptation to my new lifestyle continue that I will be able to chase the Olympic Trials marathon standard. I don’t have a deadline on breastfeeding, and I also don’t have a deadline for this goal–but 2016 would be nice.
OK, mamas, time to weigh in: Did you nurse while competing? Did your races times improve with weaning? When did you set your PRs?