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Intensity & Hormone Response

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We are meant to move; movement makes our brains and bodies work better (and age better!). As you know, there are tons of benefits of exercise, but different types of exercise will yield different results. Our exercise and movements should be “constantly varied” so that we can hit all energy systems, intensity levels, time and modal domains to make us well-rounded athletes, and keep us fit, healthy, and functional for life – and as we age.

CrossFit defines fitness as “increased work capacity across broad time and modal domains.” CrossFit defines itself as “constantly varied functional movements performed at high intensity,” it also specifies in its training methodology that this high intensity training style should be performed 3-5 days per week, depending on the athlete (and many other factors like goals, etc). Those other days are perfect for some lower intensity training to balance out the stressors inherent in the high intensity training. Of course, intensity is also highly relative, but this is one of the reasons you don’t see crazy CrossFit metcons in the KDA programming on the daily. We certainly do the fun, intense, traditional “CrossFit” activities, but pair them with things that will allow you to build, grow, recover, and balance your training and development as an athlete.

High intensity training serves our bodies well, but needs to be paired with and balanced by lower intensity exercise too for a number of important reasons, like the hormone levels in our bodies.

What is Cortisol?

Cortisol is a catabolic steroid hormone, and a major regulator of blood sugar. It is not “bad” or “good”, but rather an important hormone for dealing with stressors, both good and bad. It helps break down stored macronutrients for energy, and temporarily suppresses the immune system and the rebuilding of bone and connective tissues. It affects our electrolyte balance and makes us retain sodium but excrete potassium and water.

Cortisol release depends on the intensity of the stressor, which in this case, we will isolate to discuss exercise (other life stresses contribute to cortisol levels as well, of course).

  • High intensity exercise raises cortisol during and after workouts
  • Low intensity exercise lowers cortisol (e.g. walking, yoga, etc.)

Exercise can be a very “good” stressor because of all its positive side effects (not to mention the moderate stress of exercise can help us better handle other life stresses!), but too much cortisol too often (i.e. those of you metcon monsters who just try to high intensity workouts every day) is a problem. After a while, we don’t recover, and our bodies keeps getting the signal to break down stored fuel for energy, which can keep our blood sugars constantly high. Chronically high cortisol can also change where fat is deposited (upper back fat is an easy tip-off), and may suppress sex hormone production.

Temporarily elevated cortisol, when balanced with lowered cortisol from lower intensity activities and other relaxation efforts, stimulates repair and regeneration.

What about Anabolic Hormones?

These are hormones that tell our bodies to build things up (aka protein synthesis and stimulating the growth and rebuilding of lean mass). Examples are testosterone and growth hormone.

High intensity exercise stimulates anabolic hormone production, but too much too often will suppress them. Anabolic hormones go down as we age, making in harder to repair and recover as we get older, and retain lean body mass (we lose an average of 2-4% of our Resting Metabolic Rate every decade after the age of 25!)

A healthy balance of high intensity and resistance training will prompt more release of these anabolic hormones in our bodies (too much can suppress them though!)

Sleep is also a huge factor for secretion of these hormones, but that should be old news to you by now!

Find the Balance:

Both types of exercise will help you:

  • Calm your sympathetic nervous system down, lowering perceived stress over time. (To continue the effectiveness, you have to increase the workload according to your adaptation)
  • Improve insulin sensitivity
  • Get fatty acids out of storage, transporting them, and using them for energy

That’s why there is a method to the perhaps-seemingly “randomness” of the CrossFit programming; we don’t want to clobber you with crazy intensity each day, as it’s simply not healthy or sustainable. That’s why you see days with intensity flanked by days with just lifting, or a longer, slower workout, for example. Trust the process; we are building whole, healthy, balanced athletes who are training for function, health, and fitness FOR LIFE! 🙂