why no muscle pain after fitness?

Question

I just started doing weightlifting. The first time I had quite a lot muscle pain, however I just purchased some dumbells and started to work out with these. I did bicep curls,hammer curl, bench concentration curls and zottman curls and tricep dips to work out my arms. My biceps were really exhausted (wasn't able to get the weight up anymore after I finished). The next day I was suprised that I had no muscle pain at all. So this raised a question:

• I KNOW that muscle pain is not linked to muscle growth, however when having muscle pain it is hard to lift some weight the next day (which kind off tells me that they were charged good last workout) So it's quite counter intuitive to me that no muscle pain is "good" because without the muscle pain I can workout fine the next day. So I'm interseted in what causes it that I don't have muscle pain after a training which really exhausted my muscles?

(P.s I have already read some topics about no muscle pain and intensive training: 1, 2, however they all say: "it's not related" however I'm interested why this is the case)

Answer 1

Think of it from a survival stand-point. To your body, working out is an environmental hazard that it has to adapt to. For example, it doesn't equate bench pressing as "a workout" or "an exercise". It just knows that, for whatever strange reason, you need to bench press a lot. It needs to adapt to this environment where you bench press a lot, so it increases its ability to bench press so that it can better handle this environment and increase your chances of survival.

Normally, you would not get to dictate when you need the ability to do something. You either are capable of doing it or not. So in this bizarre reality where you're constantly bench pressing, you need to be prepared for it as soon as possible. You would (to your body) risk serious harm or death if you couldn't do something because your muscles were too sore from the previous day.

Now, the reason why things hurt like crazy at first is the body doesn't necessarily want to be in this environment. It takes energy to be adapted to such things, so it wants to use that energy to adapt to the environment that it's currently in.

Answer 2

This is my best attempt to explain this phenomenon. No doubt someone has studied this more than me, but here is how I see it:

I will highlight some things that you already know beginning with your very first workout..

1. After intense use, your muscle has small tears.
2. Your muscle urgently requests resources to begin repairing and rebuilding for the next intense use.
3. Your muscle sends pain signals to your brain.

Now lets observe this, briefly, from an evolutionary perspective..

• In the past you needed your muscles to acquire food and resources in order to survive
• Pain is a negative reinforcement for "bad" behavior

When your muscle tears, and your muscle sends pain signals to your brain, it is effectively incentivizing you to rest that muscle. This prevents you from damaging your muscle even more, which takes much longer to repair, and causes you to lose muscle mass, which ultimately makes it more difficult to acquire food and resources (less muscle, less food right?).
In effect, the pain discourages you from weakening yourself.

Why does your muscle eventually stop sending pain signals to your brain?

• Your muscles have been able to repair themselves successfully several times
• Pain requires some attention and can be quite distracting

Your mind at this point realizes that your muscle is going to be used intensely repeatedly, and it will usually be given the proper amount of rest. And also at this point, your mind begins to drop or "ignore" the signals sent from your muscle (or muscle stops sending signals.. not 100% sure). This has some advantages from a survival standpoint:

• It is much easier to repair your home or prepare for a harvest without aching muscles
• It is much easier to, say store food for the winter, without aching muscles.

These tasks require minimal muscle usage compared to intense workouts and were paramount to survival for many people across the world. This ultimately helps you survive.

Basically, reduced muscle soreness helps you do your day-to-day stuff more effectively in a modern day scenario. In the past it helped you focus on staying alive.

P.S. I almost included that surviving a sudden bear attack would be hampered by sore muscles, however a different adaptation occurred that suppresses pain, increases strength, focus, and senses. This one is called adrenaline.