Brook was speaking at England’s first training session in Barbados before the opening match of their T20 World Cup defence on Tuesday against Scotland at 15:30 BST.
He appears leaner and said he used his five months at home to work on his fitness, having had a busy first 18 months of his England career playing across all three formats since his debut in 2022.
He hopes improved fitness will help him run more twos in the heat and humidity of the Caribbean and help have “fast hands” to aid his power-hitting.
“I did try and nail as much practice and fitness as I could and get myself in the right headspace,” said Brook, who made one half-century in England’s disappointing 50-over World Cup campaign last year.
“I was travelling a lot so to have that little break from cricket was good and I was raring to go again when I went back and played for Yorkshire.”
The weather has been mixed since England’s arrival in Barbados on Friday – hot but with short, heavy showers – and similar weather is forecast for Tuesday.
England are in a group with Scotland, Australia, Oman and Namibia and an early washout would add pressure to later games with the top two progressing to the Super 8 stage.
There is an extra 90 minutes available to complete morning games interrupted by weather. The shortest possible match is five overs per side meaning a match would need to be begin by 19:00 BST.
“Every game is important in a World Cup,” Brook said.
“We’ve just got to hope and pray the weather does stay away and we can get a game in.”
England’s XI will likely match those in their rain-affected series win over Pakistan with the main selection call being between left-arm seamer Reece Topley and fast bowler Mark Wood.