A major effect that extreme exercise has on our bodies is an immediate increase in cortisol, the hormone that is released when the body is under stress. Heavy-resistance exercises are found to stimulate markedly acute cortisol responses, similar to those responses found in marathon running. Chronically high levels of cortisol can increase your risk for a variety of health issues, such as sleep disturbances, digestive issues, depression, weight gain, and memory impairment. Excess cortisol also encourages fat gain, particularly around the abdomen.
Overtraining can also have harmful effects on the immune system. Research has shown that the cellular damage that occurs during overtraining can lead to nonspecific, general activation of the immune system, including changes in natural killer cell activity and the increased activation of peripheral blood lymphocytes. This hyperactivity of the immune system following intense overtraining can possibly even contribute to the development of autoimmune conditions.Although there's not yet a device you can put around your wrist to tell you you're overtrained, there are signs. Mark Sisson's 8 signs of overtraining (from here):
1. You repeatedly fail to complete your normal workout.
2. You’re losing leanness despite increased exercise.
3. You’re lifting/sprinting/HIITing hard every single day.
4. You’re primarily an anaerobic/power/explosive/strength athlete, and you feel restless, excitable, and unable to sleep in your down time.
5. You’re primarily an endurance athlete, and you feel overly fatigued, sluggish, and useless.
6. Your joints, bones, or limbs hurt.
7. You’re suddenly falling ill a lot more often.
8. You feel like crap the hours and days after a big workout.
You'll need to ratchet it back down if these markers describe your situation. Here are a few techniques to avoid overtraining while still enjoying high intensity exercise:
- Reduce the frequency. While pushing yourself hard at the gym is not inherently problematic, doing it too often during the week is overtraining. High intensity, high stress exercise should be limited to two or three times a week, especially for those who are dealing with other health issues such as autoimmune conditions or digestive troubles. Compounding those stressors with extra stress from your exercise routine will not leave you healthier, and can easily cause you to become more sick.
- Get adequate rest. I’ve written before about how important sleep quality is for health. Not only is taking breaks from exercise important, but getting adequate sleep to allow recovery from intense exercise is vital to avoiding the overtraining syndrome. Make sure you are getting adequate sleep, particularly on the days you train. Interestingly, one symptom of overtraining is disturbance of sleep, so if you’re feeling restless and having trouble sleeping through the night, you may want to reconsider the intensity of your training schedule.
- Mix it up. While high intensity exercise may be ideal for losing body fat and improving lean muscle mass, we know that high levels of cortisol can cause the body to hold onto fat. For this reason, you may consider trying a type of exercise that can help modulate your cortisol levels. Some may knock yoga as being too easy to affect weight loss, but regular yoga practice is shown to reduce cortisol levels, which may help in reaching your weight and fitness goals. Instead of doing a fourth day of CrossFit, try doing a yoga class instead. You may find that this stress reducing exercise helps you recover more quickly from your more intense exercise schedule.
- Eat more carbohydrates. While cutting down carbohydrate consumption is often seen as the best way to decrease body fat, a combination of overtraining and low-carb eating can actually raise cortisol significantly and negatively impact immune function. There is also a possibility that very low carbohydrate (VLC) diets suppress thyroid function, a debate thoroughly discussed by Paul Jaminet on his blog. So if you’re regularly doing high intensity training and want to avoid symptoms of overtraining stress, don’t skimp on the carbs!
Thanks Chris Kresser and Mark Sisson for breaking it down for us!