This happens to me as well! My working theory is the that I deplete all the dopamine during the run. I'll usually feel total contentment for awhile before it settles in. Since I don't have anything to be depressed about in general, its easy to see it for what it is and wait it out with some nutritious food and sleep.

Eat fish after exercise. It helps

> Since I don't have anything to be depressed about

I think this is a case where a word is used in two different ways and it is important to be clear to keep the intended meaning clear.

"I'm depressed that she turned me down" is a very different kind of depression than clinical depression. There doesn't have to be any external negative condition to cause someone to have clinical depression.

As far as I know, when people talk about using ketamine to help depressed people, they are talking about hard to treat clinical depression, not the short term state of disappointment or sadness that people also call depression.

Wow. Neat to hear it’s not just me! I wish someone would study it. I couldn’t find anything last time I searched for it. I’ll try fish next time.

Sounds like depletion of something, perhaps in the energy metabolism pathway, such as thyroxine.

There are some links between inflammation and depression. Perhaps taking an anti inflammatory the day after working out would be helpful.

Or instead of training to failure, do one of the work out protocols that specify maintaining control and staying out of injury and inflammation territory, such as the Quick and the Dead, kettle bell protocol.

Routine use of anti-inflammatory medication isn't a good idea for most people. Inflammation isn't a bad thing, most of the time. It's actually a critical part of the body's repair mechanisms.