The most common and most likely answer to this crossword clue is the 8 letter word AEROBICS
I've seen this crossword clue in The Daily Telegraph
A
E
R
O
B
I
C
S
More clues leading to the result AEROBICS
- Flying stunts, not at these exercises
- . Chocolate bar rubbish when taking running exercises
- Exercise or basic moves embracing sweetheart
- Energy invested in basic or dancing exercise
- Tossing caber, so I will find a way to keep fit?
- Exercises a drag to set up, in charge of Seconds
- Care is arranged, old boy being kept inside for exercises
- Flying manoeuvres abandoned at exercise
- Exercises that could lead to ‘bio-scare’
- Tossing caber is about love for exercise
Buddy explains!

The straight part
We know that "exercise" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case exercise = aerobics.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does AEROBICS mean?
AEROBICS noun- A form of exercise, designed to enhance one's cardiovascular fitness, normally performed to music.