Jornal de grand89, 18 out 17

Sounds like the effect on the body was more "strength training" than it was simple "aerobic activity" - methinks you built a little muscle mass, sir. 

You know what Grand89?! That ALWAYS happens to me. Anytime I increase my activity, my weight increases too. I know that it may be muscle mass, but its confusing to me at times  

Sounds like muscle mass. Also how does your body feel to you? Do you take before and after pics? I have learned sometimes those are more important than the scale... unless my body feels sluggish and like it has back peddled. 

making muscle my dear 

That's muscle! Good for you. 

Inflamtion from building muscles 

Inflamation and water load or possibly just re-hydration...with a day or two of low activity you'll be back to, or under normal weight. 

Maybe too much sodium and you have water retention? Or maybe increase in muscles.  

No worries, if you feel a little soreness the slight gain may likely be from water retention... 

Muscle hold water after intense workouts! 

And that is why people shouldn't concentrate on "numbers on a scale". Measurements are the best way to track your fitness unless you are talking huge gains/loss, then obviously those numbers hold more significance.