Exercising too much can affect your brain as well as your muscles. Athletes and dedicated exercisers often suffer from an overtraining syndrome in which their performance drops, their muscles feel sore and they are tired all the time. In a new study, elite athletes were instructed to overtrain for three out of nine weeks, and were then compared to a group who did a normal nine-week training program (Current Biology, September 26, 2019). Not only did the overtrained athletes perform worse on endurance tests, their brains were affected as well as their muscles and other body functions. The overworked athletes suffered from mental symptoms including depression, irritability, restlessness, insomnia, and loss of appetite. They also made poor decisions in special tests such as choosing meager immediate personal rewards over more substantial delayed rewards (i.e., taking $10 now rather than $50 in six months). MRIs of their brains showed markedly reduced activity of the lateral prefrontal cortex, a key region in which a person makes important personal decisions. This study agrees with a previous study that used MRIs and tests to show that overworked office workers made poorer decisions and had reduced activity of the lateral frontal cortex of their brains (Proc Natl Acad Sci USA, 2016; 113: 6967-6972).

Signs of Overtraining
A regular exercise program is supposed to make you feel good, increase your energy level and help to control your weight. You may be exercising too much if you feel:
• tired all the time
• irritable
• unable to sleep
• loss of appetite
• no improvement in your performance over an extended time
• no enjoyment of exercising
You may also have:
• frequent colds
• increased resting heart rate
• reduced maximum heart rate
• persistent muscle soreness
In particular, muscle soreness on one side of your body or localized discomfort in one part of your body are major signs of an impending injury.

My Personal History of Overtraining
Athletes train by stressing and recovering. You make a muscle stronger by stressing that muscle, feeling sore on the next day, and taking easy workouts or days off until the soreness goes away. Then you are supposed to take a hard workout again. If you do not feel muscle soreness on the day after a hard workout, you have not injured your muscles and they will not become stronger. Sometimes your muscles still feel a little sore several days after a hard workout, but you think that you have recovered and are ready to stress your muscles again, so you go ahead and try to run very fast. You start to feel sore all the time, your joints, muscles and tendons ache, and you feel tired. You can still run with the soreness in your muscles and tendons, but the soreness prevents you from running fast. Each succeeding day, the soreness increases and you think that you are sick.

This happened to me when I was training for a marathon, so I ordered tests including a complete blood count, liver tests, BUN, creatinine, urinalysis, and a throat culture, but all the results were normal. I couldn’t run my intervals as fast as usual. I had been able to run 10 quarters in 65 seconds and now I couldn’t get through more than three of them without my muscles feeling very sore. I knew something was wrong, so I asked a friend who was a researcher at a nearby university to test me. He told me that I had impaired anaerobic lactic acid clearance and a reduced time-to-exhaustion in standardized high-intensity endurance exercise tests. My maximum heart rate was 10 beats lower than normal, my lactate levels were lowered during sub-maximal performance, and I had a reduced respiratory exchange ratio during exercise. By now I was quite depressed, so I got further tests and decided I might have a hidden lymphoma, but my complete diagnostic workup was normal. I was stuck with a diagnosis of training too much.

Recovery from Overtraining
When you are suffering from overtraining, you need to go back to background work. These principles apply to any sport. For a runner, jog on the days that you can. Take days off when you feel sore. After several weeks, you are able to start regular jogging and your muscles feel fresh again. When this happens, you are ready to start training, but first you must promise yourself that you will never try to run fast when you feel soreness in your muscles and tendons. Set up a schedule in which you take a hard-fast workout, feel sore on the next day, and then go at an easy pace in your workouts until the soreness has completely disappeared. You may set up a schedule to try to take a hard workout every third or fourth day, but you will skip a hard workout on any day that you feel sore.

Most runners plan to run very fast once a week and long once a week. You recover faster from a hard workout by doing nothing, but jogging slowly on recovery days causes more fibrous tissue to form in your muscles so that they are more resistant to injury. Don’t calculate total miles per week in your diary; that will encourage you to pile up junk miles and prevent you from learning how to run fast. You can run in races only as fast as your fastest workout intervals. Set up a program in which you run very fast on Wednesdays and long and brisk on Sundays, and make all your other workouts easy recovery ones.

Competitive runners usually use interval workouts to increase their speed. When you have recovered from overuse syndrome, you should start with short intervals before you try longer ones. For example, you could start with 110 yard intervals. Mark the track in quarters, using the fifty yard lines and the middle of the goal posts. Alternate running 110 yards fast and comfortably, and jogging 110 yards until your legs start to feel heavy and stiff. When you can run at last 20 repetitions of 110 yards fairly fast, try do repeat 220s, and as the weeks progress, work up to repeat half miles. Don’t try to run through the stiffness or you will take weeks to recover. If your legs are exceptionally sore, take the next day off. If they are not sore, jog easily on the next two or three days.

Use your Sunday workouts to try to gain endurance. Your endurance day should not be as fast as your interval day. Each Sunday, try to work up to where you can run fairly fast for up to two hours. You may have to start out with a long run of only 30 minutes, but be patient. Lack of patience can lead to overtraining syndrome. You should eventually be able to learn how to train without injuring yourself and avoid making the same overtraining mistakes again.