I play 4-5 times on the weekdays, around 2-3 hours each time on average. I drink a lot of water and take a banana or two to keep my energy levels up during a hit or match.
After a long lay off the first couple of lessons I had made me so tired I vomited when I got home.
Now, my post hit recovery involves a cigarette and a can of coke.
But as I play more I get less aches and my body recovers enough to play hard the next day.
I am over 40
For me, tennis is my fitness. I am not advocating my post game recovery routine, but the fact I just get on court a lot trumps everything, in my book.