Exercise, Stress And Cortisol: What You Need To Know Right Now
Exercise, stress, and cortisol.. How do they all relate? What's this mean for you and your goals?
Because cortisol plays a role in things like metabolism regulation, controlling BP, salt/water balance, mood, and blood sugar levels, there's a lot of things going on at once that makes for a complicated picture.
So, let's start here:
Everyone one of us has a cortisol rhythm that we can graph out like in the picture below. We call this a cortisol curve, and for the most part we want the shape of the curve to be the same for everyone- Higher in the morning, drops sharply midafternoon, and continues to gently decline as bedtime approaches.
This curve should align with the day/night or light/dark cycle. So, when we wake up we need more support to get our bodies through the everyday, good/bad stressors that is part of life, and we need less as the day goes on and we prepare for sleep.
When this curve is altered in any way, we see symptoms. For example, if after dinner your cortisol levels rise, you may struggle with insomnia or poor quality sleep. You might wake up feeling irritable, anxious, and still tired. If your body is very stressed, you may not get that morning spike, and your curve is flattened. You feel like you can barely drag your body through the day, but then are a bit on edge at night. This often leads to that coffee/wine diet so many of us fall back on to help deal with our lagging energy and crazy high stress levels- which then perpetuates the problem!
Ever noticed that if you miss that magic window of getting your kids to bed and they stay up late, they seem to get up earlier than usual and are grumpy? That's because their cortisol levels rise from the stress of not getting to sleep when they need it which then interferes with their ability to sleep. (ugh.. My husband still doesn't get this and lets our 18 month old play when she doesn't go down easy.. *sigh*)
It's easy to observe this in babies because they don't have anyone telling them to suck it up so they can get the kids to school and then be on time with a smile on their face for their morning meeting at the office. They just cling and fuss all day until they get some good sleep.
Where does exercise fit into this?
Well, exercise causes a cortisol spike due to the stress it places on our bodies. Remember, we WANT some stress to our tissues so that our bodies will adapt and be stronger. However, if we get that spike right before we go to bed, we're probably going to be like our kids and not want to/be able to fall asleep at a decent time. Even if we do, the *quality* of sleep we're getting may leave a lot to be desired.
What we do know is that an exercise-induced cortisol spike that occurs when our cortisol is naturally higher will impact us less than when our cortisol levels are naturally lower. Also, some activities create more of a spike than others. Running, for instance, will increase our levels higher than walking. And restorative activities like yoga have been shown to DECREASE cortisol levels.
This is why some women may actually lose more weight and feel better with less or less intense exercise. For instance, if Nan wants to lose weight and has a cortisol curve that's flipped from other stressors in her life, starting a running program after work may actually cause her to GAIN weight.
However, if she starts a restorative yoga practice before bedtime or goes on some easy walks in the mornings, this may not only help her achieve her weight loss goals more easily, but it may also provide additional healing benefits if it helps her normalize that cortisol curve.