As he charged all afternoon to secure his 55th F1 win, Lewis Hamilton often sounded out of breath whenever he was heard on his team's radio, an indication of just how physically demanding his work behind the wheel was on Sunday.
The Brit admitted that Formula 1's new-spec cars were physically a difficult proposition compared to last year.
But the three-time world champion also insisted that some races were simply more difficult than others to manage.
"The cars are a lot more physical," conceded Hamilton.
"The thing is, there are different races. A lot of races we do are strategic, when you have to not use your energy and save the tyre, and save the fuel and make the tyre go the distance.
"And sometimes you balance where you can push harder. I don't remember having a race like this in a long time where I was able to be on the limit as hard as I was and stay within a battle. "
Interestingly, Hamilton parted ways with his personal trainer at the end of last year.
He now conducts his physical training on his own away from the race track, but still relies on the presence of physio Angela Cullen for his preparation during race weekends.
"It's been along long time, so I used up a lot of energy and I'm looking forward to laying down after this.
"And that's' how it should be, you should feel physically depleted at the end.
"When I jumped on to my team my heart rate went through the roof, and then when I got to the top of the stairs I was really struggling to catch my breath, because the emotions and everything...
"I've been racing for 24-25 years and it feels like the first win."
Win the ULTIMATE TRACKDAY with F1i.com!
GALLERY: All the action from Barcelona on Sunday
Keep up to date with all the F1 news via Facebook and Twitter
