It's always an honour to communicate with a real Socrates

I didn't knew he spoke English, in his days the languish didn't even exist..
Anyway on over training and apnea.
Through my 6 years of apnea training I notised it' easy to overtrain swimming in water, and it's even easyer to overtrain apnea.
Often I did a nice relaxed training doing apnea, and feeling energised and not very tired after. Arriving at home, having eaten oranges, bananas, sportsdrinks, suddenly the tiredness became apparent.
The amount of tired ness seem to follow a parabolic curve.
If for instance your dynamic pb is 100m.
You'll experience much tiredness afterwards at home, and need to wait something like a week to a month to be fully recoverd from this maximum attempt.
On the other hand if you do 90m you'll be able to do that every week
an 80m you could do every other day.
With Samba's or -worse- a Bo, you'll for sure need lot's of rest to recover, especially if you were already a bit tired and did not get any additionnal O2.
With 5 water times in a row in a week I would need to compartimentalise my training. For instance:
Monday, Dynamic monofin (emphasis on strenth and stamina, mostly surface swimming) Stretching
Tuesday, Stretching, Static and no fins, Stretching
Wednesday, Dynamic monofin After general warmup 16x50m, 2x50 slow, 2x50 fast etc. Stretching
Thursday, static, No fins, Stretching
Friday, Dynamic, long and slow dives (the '80m' category)
When your'gettign tired, it's time to focus on and maintain a good coordination and technique. Like my monofin trainer said: "when your tired the real training starts".
I would shift much of my regular gym's exercises to the pool training, and do more stretching in the gym, ribcage, diafragm etc.
Have good food and fluids and plenty of sleep!
Start slow, build up gradually, your body needs time, month(s) to adapt and getting used to apnea workout, it's a big change from earobic exersising.
I hope you find this usefull, Have and retain the fun!
Share and double the fun with a buddy.
Love, courage and water!
Kars